Fox T-Bird/Cougar Forums

Hello Gentlemen,

I've been visiting this forum a lot for a long time now, ever since I first started to love Fox body Fords. This is my first time actually making a post, as I have finally encountered a problem I can't nail down. I've seen a lot of problems get solved on this forum. I'm hoping mine can soon be one of those.

Here's everything I know so far:

The Car:

 - 1984 Ford Thunderbird (my second Fox-Bird)
 - 5.0L (302 CID)
 - CFI (Central Fuel Injection)
 - EEC-III (No OBD or self test connector. Limited trouble code ability available by attaching a 12V test light to one of the solenoids.)
 - Duraspark III (Non-adjustable timing. Distributer is basically just a shaft with a gear on one end and a rotor on the other. Computer judges spark advance/retard using a crankshaft position sensor.)
 - Recently redid the exhaust system. Ditched the old pipe and replaced it with some 2.5 inch truck pipe I had lying around. Glasspack ler.
 - Removed the A/C because it didn't work and was in the way.
 - New air filter, recently changed all fluids and filters (including fuel filter).
 - New ignition switch.
 - Added water temp, oil pressure, and volt gauges.

The Problem:

... is a surging rough idle that occurs only in park and neutral. The rough idle and surge exist at any RPM. If I shift into any other gear the surge stops, the engine smoothes out and any other negative sounds disappear. The car drives like normal (actually it drives GREAT). No stall or hesitation. The surge immediately returns if I shift back into neutral or park. The only other symptom is high NOX in my last smog test. (Test was done yesterday. Everything else tested well within the "green".)

What I've tried so far:
 - New rotor, plugs, dist. cap, plug wires.
 - Replaced voltage regulator because it looked like it'd seen better days.
 - Checked base timing, all good.
 - Removed EGR and the throttle body and gave both an extremely good cleaning. (EGR looked new when I was done.) All new TB and EGR gaskets.
 - Tested EGR position sensor: good. Replaced o-ring anyway.
 - Replaced all nylon vacuum lines with steel vacuum lines. I got tired of them breaking. There are definitely NO vacuum leaks. Vacuum off the manifold measures at about 17 inches. I'd expect it to be higher, but I think once this surge is gone it will be. No fluctuations in vacuum during surge.
 - Examined the entire wire harness. Fixed any exposed wires or cracked insulation. There are no ground faults or broken circuits.
 - Opened EVERY wiring connector and thoroughly cleaned all of them.
 - Adjusted the curb idle to no avail (if anything, now it surges more).
 - Tested all solenoids, all good.
 - I attached LEDs to the solenoids to see when which were getting turned on by the computer and checked to make sure that they were indeed coming on.

Everything seems to be functioning normally.

I reset the computer and then drove it for 15 miles after every one of these changes. Sometimes there is no idle surge after resetting the computer. But then I pull into my driveway thinking it's fixed, shift into park, and start banging my head on the steering wheel because the surge is back again.

Other than that I've been poking around with a multimeter, unplugging sensors to see what happens, reading A LOT of articles and forum posts and getting really frustrated.

I wish the car was either EFI, so my problem would be the IAC (there is no IAC in CFI), or a standard carbureted system, so there would be no computer or electronics to argue with (like my dad's 400). Instead I'm stuck somewhere in the middle.

My current suspect is the electric choke and crank position sensor, as I'm not really sure how to test them (other than sticking a voltmeter on there and going "yup! That's a reading!").

I'll try to make a video of it and post it to YouTube tomorrow. No promises though, the internets are a bit slow around here.

Also check your fuel pressure regulator.  it could be sending a little too much fuel into the TBC at idle resulting in a "rich" mixture and high RPM but not enough to be noticble under any load or while driving.  If this was a 1930's car you would say it had a carburator issue - the FPR is part of the "modern version of the carburator".

Check the grounds and wiring on the O2 sensor if the computor gets the wrong signal it will act on bad info.

One or more sensors could be marginal - checks out within specs but is not 100% effective all of the time.

Filmore
51 Dodge with the original flathead - only one vacume line, & manual choke on a Carter B&B Carb.  Had a push button starter before all those fancy your-o-peeing cars.  65 horses -count 'em. 4 on the floor.  a man's truck.  "the computor is in your head".

A long time ago when my 84 still had the CFI, I had the same problem. I went through what you are going through now. In a nut shell, I found the wiring harness going to the dist had wires with brittle insulation inside the plastic wire loom that would touch intermittently and cause the problems listed above. That might be it......might not, just my personal experience.

is the TPS new?

oh wait? does it have one on an 84 cfi?

 
It does. I picked this car up off of craigslist for $300. Great deal, but there are a lot of hillbilly repairs that were done to it over the years that I've been going over and making right.

The TPS looks newer than the rest of the throttle body, but I've never replaced it.

However, after today I am definitely suspecting my fuel delivery system. I did a pressure test and I was getting 45 psi while the engine was running, but zero psi just before start and right after shut off. I replaced the fuel pressure regulator valve and that fixed that.

While I had the TB off again, I noticed that the fast idle kickdown felt loose. I opened it up and the vacuum diaphragm was completely worn out. So I replaced that too.

I then did another idle speed adjustment, this time also adjusting the fast idle, and reset the computer again. Now the car runs like  in ALL GEARS. So I have somehow either made it worse or just more apparent. But, there also now more symptoms The injectors are pulsing with the surge. They spray a normal mist most of the time but when the car surges the injectors spray out more fuel. I thought that the injectors were supposed to spray fuel at the same rate all the time? Also, does anyone know what color the tops of the injectors are supposed to be? Because these look green and I thought the 302 injectors were blue. I have a lot of injectors lying around from other cars. I've heard of people using CFI injectors in EFI, anyone ever tried the other way around?

At the same time my throttle kicker actuates a little bit. It had not been doing this before, but it makes sense that it would.

Also, as far as any wires going to the distributor this is a Duraspark III so there a none except the one from the coil and the plug wires.

I just know that when I do find the problem it is going to be something bonehead stupid obvious and ridiculously expensive. Btw, a new fuel pressure regulator is $100 from CarQuest. Thought I'd mention in case anyone ever ends up needing to find one.

With a working regulator you should get 39 psi and it should hold that pressure for a good long while after you shut off the engine. My new regulator takes an hour before the gauge drops a little.

Also, I figured out how to test the electric choke and it seems to be fine. Mine draws about half an amp while the engine is running which is supposedly normal according the the shop manual I have.

Your original post sounds very similar to my currently being ignored issues.  Except if I don't warm her up till the needle gets on the blue bar she dies when you put her in reverse.  But, since my car rarely idles longer than it takes to warm her up I'm ignoring it till I have the funds to get a code scanner, from there I'll decide depending on the issue whether to go carbed or to just fix the issue.

Seems to be a common problem for the 83/84 5.0 and if you do a search you should find several folks asking the same question without a definitive answer. I had/have this problem on my 83 from time to time and I actually recall it doing it when it was still fairly new.  I've been collecting some spare electrical parts to swap next time I have the problem to see if anything works. At one point I thought it was fuel related since it would occur more ofter right after I filled up the tank. Don't know if the carbon filter/etc would have anything to do with it or not? It's aggravating and difficult to diagnose when it happens.

EEC-III is useless for codes.  I just picked up a Ford EEC III - EEC IV Training  Program 5-Day Technician Certification manual so I should be able to fix anything soon! :hick:

Good luck, keep us posted.

An old mechanic friend had a throttle body and intake from an 85 5.0 Tbird laying around which he gave me for the parts. His TPS was newer than mine so I went ahead and swapped them. Now the car will idle, but refuses to idle at less than 700 to 800 RPM. If I set the curb idle any lower than that it starts surging again. However, I think I've at least figured out why it's surging, though still not what's causing it.

It doesn't feel like a hunting surge where the computer can't find the right idle speed, it feels more like an emergency response. If I lower my curb idle to where 550 RPM should be and then watch the tach I can see that the RPM lowers to almost 550 or 600 and then it surges up to 800 and then slowly goes back down to 600 and then surges up to 800, etc. etc.

I think that the car is about to stall at low RPM and it reacts by kicking the throttle for a second, then it slowly returns to my curb setting. This is supported by the fact that with the idle set that low the car will not start. I have to set the idle up a bit to start it and then lower it again. Trouble is I can't pass smog with the idle up around 800 (I got a "Idle RPM Outside Manufacturer Spec." checkmark on my smog sheet) and the car can get up to 20 MPH just with the gear engaged, so a slower idle is a must have.

Another interesting item is that the computer adjusts the timing way off from the base. The base time is 10 degrees BTC, but while it's running it reads as 20 degrees BTC. Is this normal or is my computer really compensating for something?

A couple days ago I purchased a new multimeter. Today I decided to retest all of my electronics in case my old one was really on it's way out and giving false readings. I discovered:

1. My EGR Control solenoid is bad.
2. My old TPS (which I already replaced) is bad.
3. My O2 sensor is bad.

Things have been replaced and a computer reset is underway. Before resetting I started it up just to see if there was any difference. It started at about 650 to 700 RPM and then slowly climbed for about 5 minutes to almost 1000 RPM. Then it suddenly dropped to 740 RPM and HELD. Unfortunately it's too late to test drive. Tomorrow I will do an idle speed adjustment and then, if I wake up early enough, drive it to church. Good Lord willing, I'll have a fully functional 5.0L Thunderbird tomorrow! :D

Interesting, I was gonna replace my TPS but can't find one anywhere lol.  Hope this fixed it for you.

Well, I think replacing the O2 sensor really helped out a lot. It's holding an idle much better than it was before. It still surges, but only about 30 RPM instead of 300. Now I'm trying to test my other sensors and I've hit a snag.

What should my B/MAP sensor read at 0 in. vacuum? It's EEC-III so it's a two in one sensor (both barometric and manifold pressures) with a 9 V reference (instead of 5 V like the EEC-IV and up sensors). But I have no idea what my signal voltages should be. Both baro. and man. signals are reading close to 7.5 V with the key on and engine off.

The output of the MAP sensor for EEC-IV is not a DC level. It is an oscillator and the frequency changes with pressure changes.
However baro and manifold pressure should be the same when the engine is not running.

I'm thinking an EGR problem... you mentioned the NOx test failure... that generally indicates the EGR system isn't working correctly due to being gunked up with carbon or not opening due to a leaking diaphragm.  Since the EGR also affects the idle if it activates while idling or leaks past the pintle, I can't really help diagnose, it's going to depend on which EGR system Ford used on that year's engine.  My books aren't much help telling which yours has.  Definitely, check for vacuum leaks through the system though, it's a good idea any time there's an idle issue. 

I'm not sure if this is applicable... but a roommate of mine had a mid-80s Escort with the CFI setup.  His problem was that the engine would idle correctly, but if you tried to drive off it acted just like low fuel pressure, extreme surging of engine power, like maybe a plugged filter or bad fuel pump.  We changed the fuel filter and I checked his fuel pressure and it was fine.  After a LOT of research I found a note on a mechanic's website mentioning a CFI Escort which they called a factory tech in to fix... turned out that the problem was part of the idle positioning system.  The actuator that set the throttle position also had an integrated switch, when the throttle closed down (foot off the pedal), it hit that switch and changed the fuel delivery system over to lean-burn to reduce emissions at idle.  His switch was bad, and he was essentially trying to drive with it in lean-burn, which does NOT work well. :)  Changed the throttle positioner, about 90 bucks, and he got a working car.  Just a thought.

BTW this Chilton's I have that covers your year of engine looks to have the same throttle actuator, the ISC [Idle Speed Control] DC motor actuator.  The lean-burn mode control switch is internal to the device, not separately changeable.  I checked it by hooking an ohmmeter to the switch contacts on the ISC connector (with it disconnected) and hand-actuating the switch, and it was intermittently working.  it's odd that that lean-burn functionality is barely mentioned anywhere in the various things out on the Net... I'd likely never have fixed his car if I hadn't stumbled across that note.

 It's true that the output of the EEC-IV MAP sensor is a frequency, but the signal output of the EEC-III BMAP sensor is a DC voltage according to my multimeter readings. I get nothing for frequency, but when applying vacuum to the ports I get a voltage signal that goes up and down. I thought that the sensor on this car uses a frequency signal too, which is why I bought a new multimeter with frequency.

What I meant by "reference voltage" is the voltage coming from the EEC module to the sensor that initializes the sensor, not the incoming signal. This is 9V for the EEC-III and 5V for the EEC-IV.

Unfortunately, without a table or curve to look up the pressures, I have no idea how accurate my sensor is. Tables for an EEC-IV MAP sensor are easy to find, but not so for the EEC-III BMAP. I have four wires coming out of my sensor: ground (black with white stripe), 9V reference (orange), barometric pressure signal (dark blue), manifold pressure signal (green).

I did find a manual for a scan tool that says the "self test" initiates when the voltage reading from the BMAP jumps over 6V and that with the engine off the sensor should read less than 3V. The manual wasn't clear if this was just the barometric signal referenced to ground or the voltage difference between the two signals. If it's the difference between the signals I'm fine, if it's not, then my car is continuously running the self test (not likely).



My initial thought as well, and the EGR was severely gunked, but giving the whole ERG system a cleaning and test was the first thing I did and the problem persists. I have some pictures on my phone, but now it's not working... Maybe after cleaning out my phone's IAC and replacing the ECT sensor I'll upload them. :crazy:



It's a SONIC EGR (what does SONIC stand for???) mounted on a spacer between the manifold and TB with a cooler and a position sensor Tested, retested, triple tested, the EGR itself and the EGR position sensor are good.

My second thought was also vacuum lines, I didn't find any leaks in the original system, but I broke two of the stupid nylon vacuum lines while working on it. I since replaced all of the nylon lines with steel line and standard rubber vacuum hoses. I have no vacuum leaks.
 


Chilton's just seems to get worse with every new edition. I swear, every Chilton's for every Ford seems to be the same. They just cut and paste sections for the different features. I too have a Chilton's manual for my car, I use it for a coaster. (The only useful thing in it was the capacities chart, which is also in my Ford shop manual.)

Only the 3.8L had a DC motor throttle actuator. The 5.0L had a vacuum dashpot for the throttle kicker and vacuum linear actuator for the fast idle cam (part of the "cold enrichment" system I think). I replaced the diaphragm in the fast idle cam actuator and tested the throttle kicker dashpot. Both definitely move when the computer flips the solenoid that controls them (both are on the same vacuum line), so I'm fairly sure they're good.

I would try replacing the dashpot, but the car seems to be idling now. My O2 sensor was apparently the key to the large surge. However, I still have a slight surge (about +/- 50 RPM) AND the car won't idle low. When I adjust the idle speed, following the directions on the emissions sticker on the fan shroud, it gets down to the desired 550 RPM and stays there just fine (plus the small surge I mentioned before). Then if I turn off the car and restart the idle will either:
1) Be super low (under 300 RPM! It can idle at under 300 RPM! ...for about 10 seconds) and the engine stalls, forcing me to mess up my idle adjustment to get it started and stay on.
2) Be super high (900 to 1000 RPM) for about 2 minutes and then drop to 650 or 700 with a +/- 50 RPM surge.

Now here is my dad's theory, which I don't really agree with, but let's see what you guys think:
He thinks that the thermostat is either a 165 degF or the hillbillies (previous owners I rescued the car from) removed the thermostat all together causing the following:
1) The EEC-III wants the engine to stay at a particular temperature while idling, which is probably over 185. (Say, 195 or something.)
2) With no thermostat (or a low temp. one) and a halfway decent radiator the temperature never gets there so the computer ups the RPM until it does.
3) 2 minutes later the O2 sensor kicks (non-heated O2 sensor, so ridiculously long lag in initial start readings) in and screams "Too much! TOO MUCH!" at the EEC-III while the ECT (engine coolant temp.) sensor is screaming "Not enough! NOT ENOUGH!" (It's rare that my temp gauge rises above 180.)
4) Conflicted the EEC-III decides to settle somewhere in the middle, slightly favoring the O2 sensor in the interest of being "green", at 650 to 750 RPM.

My dad figures my problems would be solved with a new thermostat and possibly a new temperature sensor (of which I do have a spare....somewhere).

Any thoughts on that idea?

EEC3 wow that's amazing it still keeps going! Excessive nox is usually an indicator of egr but you say you've thoroughly cleaned and vaccum tested the egr. I remember having to take off the cfi tb the egr spacer plate and egr cooler and cleaning them all with a pipe brush. Also if there was that much carbon, the air charge temp sensor needs to be inspected and/or replaced. Tps should be adjusted to 1 volt and if replaced the small spring put back into position. Pull the dist cap and rotate the engine counterclockwise to take all the slack out of the timing chain and note the position of the rotor. Rotate the engine back clockwise and see if there is excessive slack before the rotor begins to move. The bmap used to be a high cost item and should be tested closely BEFORE replacing. Way back when EEC3 vehicles came into the shop it was 2 hour diagosis time vs standard 1 hour. Your are on the right track, keep trying and testing!

 
 Mike

Well, checked the thermostat and it was fine. If anything it was opening late instead of early, so I replaced it. Test drove it. Temperature still doesn't breech 180. Anyone know how a car can sit there and idle for an hour at 700 RPM with the thermostat closed and never reach a temperature over 180? Cuz I'm starting to think this engine defies both logic AND physics.

BTW, some helpful information I discovered recently that might be helpful/useful to people with the same year/system of Ford:

1) Bosch, original manufacturer of the O2 sensor (aka EGO sensor) for my car, say that mid 80's Fords and lower that use single wire O2 sensors should have those sensors replaced every 30,000 miles. Supposedly it'll help keep the MPGs up and make the smog tests easier to pass.

2) While the EEC-III does supply the BMAP, TPS, and EVP (EGR Valve Position) with a DC reference voltage of 9V, it DOES NOT supply the ECT and ACT temperature sensors with a reference voltage. The EEC-IV supplies its temperature sensors with a 5V reference and then measures the voltage drop across the sensor. This causes some confusion and some manuals and online materials say that the EEC-III supplies a reference to these sensors as well. However, the EEC-III, near as I can tell, is actually measuring the resistance of these two sensors directly. The black wire with the white stripe going to both of these sensors connects to pin 14 (I think that's right...) of the EEC-III module and the engine ground, this is like the COM lead of a multimeter. The other two wires (green with white stripe for ECT and green with yellow stripe for ACT) act like the red lead on a multimeter for the ECU for each sensor. This is backed up by Ford's shop manual which has a wiring diagram indicating the black and white wire to be ground and the other two wires to be signal for those sensors. With that kind of wiring the only way the sensors can give the EEC-III information is if the EEC-III is measuring the resistance of the sensors directly like a multimeter.

Checked the CATs. They're clean and clear. Engine still surges and idles high with them removed as well.

Checked codes again and for the first time I got a code 1-2, which is ... "RPM Out of Spec" ... NAW! REALLY!?!? ....uggg.... :disappoin

Okay, I think I've got it (like I haven't said that before). What is this relay: E3SB-9G483-AA? It was mounted to the driver's side fender wall, right next to the Duraspark III module. It also has "10 MIN." stamped into the top of it. One of the wires going to it had come undone. With that wire plugged in, 10 minutes after a cold start the idle goes down to 550 and holds with just a little bit of surge (20-30 RPM). I'm happy that it's finally doing SOMETHING right, but what the  is this magic relay? What does it do? It's not in any of my shop manuals, including the factory manual, and a search of the general part number (9G483) reveals it do be... drumroll please ...a relay. Woo. Now I'm just waiting for the engine to cool down so I can put the cats back on. Tomorrow, if it's still running right, I'm going to take it in to smog again.

Does your car have the standard 5 wire ignition module? I am wondering if there may be something unique for California emissions.

 
Yeah, it's a five wire. 2 on one connector, three on the other.

This morning it ran perfectly. 550 RPM at idle with the timing at 10 deg BTC. I ran into the house to proclaim victory and came back outside to find the car back at 650 RPM and 20 deg BTC again. I have the feeling my wacked timing is what's causing the high NOx in my smog test too.

I know that the base timing is set to 10 BTC, where it's supposed to be.

I'm told by the sticker on the distributer that my timing is non-adjustable, but just for the sake of arguement, what would happen if I tried to adjust it anyway?

EEC IV can add 20° on top of the base 10° for a total of 30°. So I'm not sure 20° is excessive.
I am curious how you set the base timing on Duraspark III. Since the CPS pulse goes directly to the EEC, there is no way to get the EEC out of the picture.

On EEC IV the CPS (PIP) goes to the ignition module first and then to the EEC. You disconnect the spark out pulse from the EEC to set the base timing.

This suggestion is in the grasping at straws category.
The two wire connector on the ignition module has a red wire and a white wire.
The red has 12v with the ignition in RUN. The white wire has 12v with the ignition in START.
12v on the white wire retards the spark while cranking.
Can you back probe the white wire at the connector to make sure it does not have 12v on it when the engine is running?
This is on the off chance the EEC wants to advance the spark to more than 20° and can't.

I checked the base timing by turning the crank to 10 degrees and then checking the rotor position.

I since discovered that though I cannot adjust the timing I can adjust the rotor position. Which kinda feels like the same thing to me. After playing with it a little bit, the timing did go down to 10 degrees, but eventually the computer adjusted it back to 20 degrees. There's gotta be a sensor somewhere or some other thing telling the computer that it wants to be at 20 degrees. The wierd thing is, I thought the whole point to the EEC system was to adjust the timing for different RPM to improve emissions, efficiency, etc. But it's 20 degrees at ANY RPM. Shouldn't the computer be advancing the timing with higher RPM and retarding it with lower RPM?


This is actually a good idea and falls more in the "well I've tried everything else" category. I'm gonna go try it right now.

I'm also going to try to make a trip to a junk yard soon to see if I can find a CPS and maybe an EEC-III module (just in case). Also, though I have 3 Duraspark II modules for a 5.0, I don't have any Duraspark III stuff, so I'll need to keep an eye out for that kind of stuff as well.

Oh and some advice for all you guys with early 80's Fords. KEEP THOSE EGRS CLEAN. I just found out a new one will run you over $140 and that it's such a "rare item" that CarQuest and anywhere else will charge you FREIGHT to get over here. This is for the SONIC EGR valve, without the position sensor or cooler. Fortunately my 3.8 bird uses the same EGR, so I kinda have a spare.

Voltages on the two wire connector are on/off at the appropriate times.

Well, still working on it.

I bought a complete set of 1984 Mitchell Manuals (via eBay) for the purposes of figuring out this problem. I now have a decent wiring diagram and resistance values for most of the sensors and other components.

Still, it does not give any method for testing the BMAP or the EVP. My EVP resistances match those for the EEC-IV test provided in the Mitchell manual and I'm not supposed to put an ohm-meter on the BMAP.

I would take a break from this and work on other aspects of the car (suspension, body work, interior, etc.), but I don't want to put much more money into it if I can't drive it around legally (I need to pass smog).

I've even gone as far as to verify that the EEC-III computer and the calibration module are stock (they are), just to make sure somebody didn't at one point try putting a calibration module from a H.O. Mustang or a truck in it.

There is also a note in the Mitchell manual on the first page for "Continental, Cougar, Mark VII & Thunderbird With 5.0L CFI":

"NOTE: The EEC-III system was used for the first 120 days of production for California Job 1 vehicles."

So the EEC-III was used on Thunderbirds ONLY in California and ONLY for the first 120 days. Hey! That makes this a RARE car! ;) ...woot?

I was wondering why you were talking about EEC-III on a 1984. Good ol' California throwin' in that monkey wrench. ;)

Just a thought: have you changed the camshaft position sensor at all?

Otherwise it's great to see progress and you're definitely getting there. Personally I wouldn't scoff at a 700-800 rpm idle; my '84 V6 hunts at idle sometimes and I've always considered that to be "normal".

Oh yeah, I'm lovin' California right now. Probably something to do with the EEC-IV not being approved yet. I swear CA is the worst place to live for car lovers. (Yet CA is famous for classic car shows, Beach Boys, and Jay Leno. WHAT THE HECK???)



I'd be fine with it too, if it weren't for the timing being so off, and the high NOx on the smog tests. High NOx is usually just one of three things:

1) EGR system. (My EGR is good.)

2) Exhaust leak before the catalysts. This kind of problem would probably also cause other emissions to be high. (My exhaust is good.)

3) Bad timing, usually firing too early. Fire to late = high HC, you didn't burn all your fuel. Fire to early = high NOx, fire stays in chamber for longer making the combustion temperatures of subsequent burns higher. NOx is created when the combustion temperature reaches something like 2800° F. My timing is ALWAYS 20° BTDC according to my timing light at any RPM while idling and in drive (didn't test high RPM in drive for obvious reasons). This tells me that for whatever reason the computer is not adjusting my timing properly.

Also, I need the idle to be lower than 700-800 RPM because CA smog laws require it to be within +/- 100 of manufacturer spec. which is 550 RPM for this car. So even if I solve the high NOx problem, if my RPM is too high I still fail the test. :mad:



This car has a crank position sensor (no cam position sensor) and I've checked it. Mitchell manual says it should measure 100 to 640 Ohms and I read ~400 Ohms. So as far as I can tell it's okay and I'd rather not throw $50 at a new one unless I'm certain it'll do me some good.

Let me describe my crank position sensor and how it relates to the ignition to the best of my knowledge so far:

There is a four lobe ring attached to my crank's balancer. As the crank turns the lobes pass under the inductive CPS. When a lobe passes under it, the CPS's magnetic field discharges, sending the computer a voltage signal. Each lobe is spaced evenly apart and set so that when the crank is at 10° BTDC there is a lobe directly under the CPS. The computer uses the frequency of the pulses to determine engine RPM and knows that for 10° BTDC timing to have the coil send a spark every time a pulse is detected. (The crank turns twice for every turn of the distributor, hence four sparks per turn of the crank for a V8.)

The distributor is a Duraspark III, so it's just a shaft with a gear on one end and a rotor on the other. The computer has no control over which cylinder the spark goes to. It's entirely based on the computer's faith that the wires are in the correct order on the distributor cap and in the alignment of the distributor gear to the crank ... shaft.... because the valves need.... wait.......

HOLY S***!!!! EPIPHANY! I TOTALLY UNDERSTAND THIS IGNITION SYSTEM NOW! And I have something to test!!!! Yay! :rollin: BRB. I may have just figured this sucker out.

My epiphany was to turn the crank to 10° BTDC and adjust the rotor so that it is pointed directly at #1. Makes sense right?

Okay, so new problem.

After making that adjustment I turn the engine over and it starts right up, at 1000 RPM and with a horrifying valve tick (I mean REALLY LOUD...at least to me, I don't know, valve ticks are rare on my cars). My dad was helping me and he managed to quickly check the timing before I shut it off. He read it as 10° BTDC.

Now, this doesn't mean much to me at the moment because as I've reported before, there have been a few times where the timing reads correct and then changes after running for a few minutes. I didn't give this the opportunity to run for a few minutes.

...

Okay it's a little later and I decided to try again. The idle settled at about 700 to 800 RPM and the timing adjusted itself back to 20° BTDC and the valve ticking stopped. I am beginning to think I could point the rotor any way I want and the computer will bring it back to 20° and I'm going to let it do that all it wants...in Hell....because I'm dynamiting this car.

I knew that...my fingers just didn't type it that way. D'oh.

Your state is messed up.
Couldn't you use something like this to help you?
http://www.amazon.com/CRC-05063-Guaranteed-Emissions-Formula/dp/B000CIPUR8

 
Tell me about it.

I've thought about using an additive, but I don't know if it would decrease my NOx. I've also heard that some additives can actually increase your HC.

Also, I run Seafoam or Marvel Oil through my cars on a regular basis (something like a six ounces every 3000 miles), so I'm not sure how big of a difference this stuff will make. Yes, I am a nutcase about maintenance. I learned the hard way that you keep a car maintained regularly or suffer the fate of having no car at all.

Redoing a continuity test of my computer's wiring harness, this time  using an ohm-meter instead of a buzzer tester. I already did a test for  shorts and breaks (I had none), this test will tell me if any of my  wires are acting as resistors. While I was at it I tested to make sure  there was no crossover (wires spliced together that shouldn't be). I did  this by putting one end of the multimeter into each pin of the computer  and then putting the other end of the multimeter in each connector in  the engine compartment. Fortunately/unfortunately (because it least then  there'd be something to fix) there was no crossover. So my harness is  at least routed 100% properly.

Since I don't seem to be able to put tables in my forum post (sadface), I put the table of the resistances on my never updated website:
http://crossalchemist.com/ThunderbirdResistanceValues.aspx

The most anomalous readings are the signal wires for the BMAP, CPS, and ACT sensors, each having resistances of 25 to 30 Ω. Any idea if this is big enough to cause problems for me?

Have you looked in the ignition section of volume D of the 84 shop manual?
There is a proceedure for setting the rotor in the EEC III distributor.
The alignment slot should line up with gap between the alighnment ribs at 0° with the #1 piston on TDC of the compression stroke.

Try this to get a sense of how much slop you have in the timing chain:
With the distributor cap off and the crank at 0° turn the crank backwards until the rotor goes backward. Continue turning backward until you get to an even mark like 20 or 30.
Slowly turn the crank forward (CW) until the rotor starts to move. Check how many degrees of slop you have.

I have the 1983 manual, so I have never seen that picture! My manual covers Duraspark III, same exact distributor as the one shown in your picture, so I assumed that it was the same system. But my manual gives a different method for the alignment! My Mitchell manuals (I have the 84 manuals) give the same alignment method as my 83 Ford manual, which I thought confirmed it.

My only problem with aligning it the way you've shown is that the rotor is not pointing at the #1 on the cap at 0° when set like that. It is instead right between #1 and #5. Is the Duraspark III distributor cap different from your typical Ford cap? I know there is a bi-level version of the Duraspark III, but that's not what I have (that was just in trucks with the MCU system I think). Am I supposed to offset the firing order on the cap? Can you send me a scan of that whole page? Or at least post a picture of the cap.

Thank you so much, by the way, that little nugget is probably the most helpful thing I've seen since this ordeal began.
 

Yes, I've done this. I have practically no slack in my chain (half a degree at most, not even a discernible amount). I'm considering replacing the timing chain and water pump anyway, just because I don't know this car's history and the hillbillies seem to have done quite the number on everything else. I'm planning for this car's "maiden" voyage to be a trip to Colorado to see my grandmother. Breaking down in the middle of the Utah salt flats with a busted water pump is not my idea of fun. By the time I'm done with this thing I'll probably know every bolt and weld personally and hopefully I can to put enough confidence in it to make the trip.

The Duraspark II and Duraspark III are interspersed in the shop manual. I have picked out the Duraspark III stuff.

More
oops The second part is posted first. I selected them in the correct order in the attachment routine. It seems to have a mind of it's own. It also automatically sizes it. hopefully you can make sense of it.

and more

My car hunts for a good idle RPM for awhile. After driving it usually evens out. The problem I have is when I give it any throttle it will bog, spit and sputter at random intervals. It is never the same. Sometimes low RPM, the next time high RPM and in any gear. I've turned down the fuel pressure alittle(I think) using the Gold FPR on the intake. The car will start without giving it any throttle, and will using run by itself. Before I turned that allen head screw it would never start on its own, and would run rough and overfuel extremely bad. Now it's just the very bad bog issue under any type of throttle. My throttle response is poor on the car too. I suspect part of it is due to the C4 transmission which has a rebuilt valve body and whines pretty bad.

HOLY  THANK YOU SO MUCH.

Unfortunately, at the moment I have the whole wiring harness apart replacing the previously mentioned wires with weird resistances. I'll try doing the adjustment like this when I get it back together tomorrow. Like I said though, doing the adjustment like this would make the rotor point BETWEEN the posts on the distributor cap for cylinders 1 and 5 (after 1 and before 5). Now, that seems like it would make the timing WAY too late to me, unless I do not plug the #1 plug wire into the post marked #1 on my cap, like I would for any other distributor.

You may have to pull the distributor and move it over one gear tooth.

What I mean is that the alignment groove on the lower cap does not line up with the #1 post on the upper cap.

In this picture the post marked "A" is where I usually plug in the spark wire for cylinder #1 and the point marked "B" is where the rotor points if I align it according to these instructions, right between cylinders 1 and 5. 1 has already gone by and 5 is coming up.


Below is the picture that both my Ford shop manual (83) and Mitchell manual (84) had. Otherwise the instructions were almost exactly the same. I didn't have the "alignment groove" pictured here on my distributor, so I just aligned the rotor to the #1 cylinder post on the distributor cap.



But the alignment groove is on the "adapter" (see above picture) which can only attach to the distributor housing one way. The housing itself is also notched so it can only be attached to the engine one way. I'm able to point the rotor at the alignment groove (and I could point it at the #1 post on the cap if I wanted to), so I don't think I need to move it over a tooth.

The cap is also notched and can only be attached to the adapter one way. I figured that at 10° BTDC the rotor should be pointed at the #1 spark post. Is that wrong?

The only purpose of the alignment slots is to set the relationship of the rotor to the distributor cap.
I have no idea why it isn't working for you.
When the rotor should be pointed directly at the spark plug post depends on the timing range of the engine. If it goes to 0° while cranking and the max advance is 30°, then the center is 15°.
The tip of the rotor is wide enough so some part of it is adjacent to the spark plug post throughout the timing range.
So at 0° it should be a little past dead center but not way out where you are.
In your diagram, halfway between the plug posts would be 45° of crank rotation.

But none of this has any affect on ignition timing. The quality of the spark could be affected if the rotor is too far off the plug post when it fires.

Well, it took me taking off the rotor and measuring the degrees or crank  rotation the rotor head would cover, but now I understand what you  mean. I had marked on the outside of the adapter where the rotor was  adjusted to when I first got the car and where I adjusted it to when I  replaced the rotor. The previous owner had it almost touching the #5  post, I moved it so it was dead on the #1 post. Better, but not what it  should be. I remember thinking when this all started that it was going  to be something so painfully bonehead obvious that I was going to feel  like an idiot when I figured it out.

I didn't get as much done on the wiring harness today as I would have  liked. I've decided to also cut out the Ford superglue junctions and  replace them with soldered junctions. The tape Ford put over the  superglue had crumbled away and I had two sets of exposed wires almost  touching (the neutral and positive references for the sensors). Also the  junctions looked so badly corroded (all green and what not) so my  inner-perfectionist couldn't resist cutting it out and splicing in fresh  wire.

Once the harness is all back in I'll try out the new rotor alignment. I  don't want to count my thunderchickens before they've hatched, but in  all likelihood this will solve my problems. Thank you.

Quick update:

I made the "special" Ford tool (just a stick of metal) and aligned the rotor. Now the car will start, but stops immediately. I checked all of my new electrical and everything seems fine. All of my connections are good and I didn't change anything else.

OKAY. SO.

As I said a little bit ago, all I did was:
1) Replace some wires and the Ford superglue junctions. All around improvement.
2) Adjusted the rotor alignment per the instructions posted by softtouch (which is definitely what I'm supposed to do). SHOULD HAVE BEEN a significant improvement.

What happened instead was that the car would crank, sometimes start, and then die immediately. I went back and tested my new wiring, double checked my diagrams and notes, checked fuses, fusable links, breakers, relays and everything, all good. The injectors were tossing out plenty of fuel, and increasing the throttle didn't help it stay on longer. So for the heck of it, I moved the rotor back to where I had it (pointed directly at #1) and it started right up.

....

Your thoughts?

I'm late to the party, but I chases this issue in a '84 5.0 a few years ago. I got rid of it "mostly", but replacing the rotor, new Idle Air Temp sensor, and cleaning the injectors. All stuff it sounds like you've done. Mine, after all that, would ramp up RMP's uncontrollably till I put on the brakes or floored the gas but only when it got warmed up and had been stopped and restarted with in a few hours, a new TPS did not fix.

Not sure if it helps, but this should be a sticky, cause a few things I didn't know and might have helped me as a chased mine down.

UPDATE:

So, the car wasn't running. Not even with the rotor aligned back to  where I had it (I think that was just a fluke last time that it did  start up). What it was doing was starting and then immediately dying.  Sounds like electrical, so I went over everything I did, nothing wrong  there. I then tested the entirety of my start and run circuits and  discovered that several wires were reading as zero resistance to ground,  including my running coil charge wire! Then I remembered seeing some of  the hillbillies' handy-work under the dash near the fuse panel.

They had replaced the rear window heater relay with a universal relay  that they wired directly into the fuse panel... by taking a screw and  twisting it into the slot for the fuse, bypassing all fuses. (Yes, I  nearly had a heart attack when I first saw it and it was the first thing  I removed when I got the car.) So while tracing my run circuit I  noticed that one of the wires they had spliced into for the window  heater was my running coil charge wire. I checked it out, but visually  it was fine. I saw that the wire ran into the fuse panel, which was odd  to me, because in all the old Fords I've worked on before this wire is a  dedicated wire that runs straight from the ignition switch to the coil  (with a resistor wire and maybe an ignition module in there somewhere  along the way). So I pulled out the fuse and now all the wires that were  reading no resistance to ground read as infinite resistance to ground,  the way they are supposed to! I'm putting it all back together now. So, I  know I have a fault in my warning indicator lights now (that's what the  fuse was for, which was not blown btw), but I don't care. I want to  make the car run first, then I can figure that stuff out.

This may have been discussed if so please forgive my ignorance but don't some of those early eec's have a staggered firing order on the cap. After you align the rotor, isn't there a procedure where you skip the posts as your calling out the firing order till you pass up #1?

Well, I guess I should give an update to this, though I'm not very happy about it. The car still won't start. Between cursing the car, Ford, the EEC-III engineers and California, I've been crawling all over the car, inside and out, trying to figure this out.

Originally it was running, just not running well enough to pass smog (see rest of this thread). Then I realigned the rotor (see a couple posts back) and replaced some corroded wire junctions and now the car won't run. Usually it starts and then immediately dies (close to a second or half after start).

I've gone over the entire wire harness from front to back (I even took the whole dash apart) and I have yet to find any sort of "smoking gun". I've tested the entire ignition system and replaced the ignition module. (Speaking of which, I've heard a rumor that Wells is going to stop manufacturing replacement Duraspark III modules, just FYI. I only mention it because they're the only DS3 modules I can find that are for CA and CFI. All other DS3 modules I find are marked "Exc. CA" and are for feedback carbs.)

Everything that is supposed to get voltage does, in the appropriate amounts in the appropriate modes (i.e. "start" vs. "run"). I don't have much to go on now because the car won't run, but here's what I do know:

 - My relays are all good (replaced with some spares I had, just for good measure).
 - It's not the inertia switch, starter relay (tried spare, same problem), or coil (tried spare, same problem).

Symptoms:
 - Spark seems kinda weak (my dad says it should be a bright blue spark on the tester and I see a dull orange spark).
 - I get a single spark on my tester (off the coil) when I turn the key on and when I turn the key off. I don't know if this is normal or not, it doesn't seem like it should be.
 - About 0.22 V on my ignition module's ground relative to engine ground (was 0.46 V with the old module, one reason I suspected it).
 - The positive post on my battery gets HOT after cranking. I mean temperature hot. I mean...it'll burn ya. Seems strange to me.

You guys are probably getting tired of me and this car by now, but imagine how I feel. I've never encountered a car this stubborn. You'd think they'd want to run and be fixed!

Yeah, there were two version of the Duraspark 3. One with a bi-level cap and one with a regular cap. From my research the bi-level cap was used mostly on trucks and engines with the feedback carb. while the regular cap was used with CFI and that version was CA only.

Once I get this thing fixed and working right I'll try to organize the experience and my research into some usable form (such as flow charts, wiring diagrams, etc.), I'll post that stuff here when that happens.

Only getting a spark when you turn the key on and off means the ignition module is not switching the coil ground circuit on and off.
The EEC is supposed to be getting CPS pulses and sending spark out pulses to the ignition module.

I get spark while cranking. But I also get a spark when I turn the key on and off and I was wondering if this was normal. I'm guessing that it is.

I swear, everything I test on it says it should be running, but it just isn't. Everything still gets power, I've tested everything after it shuts itself off and I still have power going where it needs to. There is something that stops working when the ignition switch goes back to "run" after it starts, but I just can't find it.

Have you taken a look at the ignition switch?

Yeah. I replaced it a month ago because the old one FELL OFF. The car was running with the new one and the voltages at the switch are good for each mode.
 
What else can cause this kind of "no run" behavior? Is there some way to eliminate the EEC itself as a suspect?

Nice thread,, good info on the rare EECIII and I will post twice for a reason.

On page 1 you said you had green top injectors.
If your interested in owning a car that runs like  and it has 8 cans,, then put a 3.8L v6 sister CFI on top of it.
You have the wrong injectors and throttle body.
see the difference below in the 3.8 vs 5.0 CFI air tunnel

The CFI on the left is for a 3.8v6,, The CFI on the right is for a 5.0L (see bottom picture)
I have a few of each and the super rare HO CFI, which you will want unless you can take your cfi apart and hone out the tunnels to allow for the larger throttle body butterflies.
Again, your butterflies on the 3.8L are too small, restrict air flow and therefor may be the one restriction that is causing the surging.
If you think about it, the 5.8cfi was only a 2 year deal in most cases and depending on region you are in, it was a 3year offer.
The 3.8L spanned 83-87,, much more junk yard availability plus with CAFE in effect, many people chose the 6cyl over the v8 because they thought they would get the big car with the fuel saver.
Your bets source for a v8 cfi would be an LTD,, look for 83 and 84 models.
The 83's had a molded addition to the pass side to groom in the vac operated idle kick down choke thingy.
I just hack sawed that part off and groomed the 83 CFI to an 84 application / style and installed it on my 87 because that was basically the last design change for CFI totally.
I would suspect from  your posts, you could reverse engineer something to work as well ,, but your CFI system is my first and most important topic I would like to see you verify.

You do know the fuel pres regulator is adjustable , correct?  pop off the freeze plug on top and lookie at whatcha fine!!!

to adjust the choke, just wait till the motor is cold, loosen the exterior housing screws, rotate the exterior plastic housing and just when the throttle plates ""JUST START" to open, tighten your screws down in place.  thats the same for a carb motor as well.

now for the long post of tid bits i want to add,,, since I went through the entire thread up to now....
Most all the below are in my diy link, however I am not a EECIII guru but do have info on it and as i see it, your in great hands as it is with softouch.






Im very familiar wtih the cfi systems and infact I will bet someone replaced your 5.0 cfi with a 3.8L unit.  The throttle plates and tunnels are much larger on the 5.0 than the 3.8L cfi.

Your injectors **must be** blue tops,,,,a must!!
Do not mix injectors, yours for the CFI must be low impedence, most multiport injections are high impedence. 

Yes your dad is correct, spark should be nearly a bluish white,, no orange allowed.

IM not sure how you ever got the car to run with the fast idle diapharm crashed like that,seems like you should have had a vac leak there , guss you got lucky and the internals didnt allow it.  New'er CFI models had a motor controled Idle control motor with an idle tracking switch , its touchy to adjust.

Yes it is normal for the eec to adjust the base timing based on the tables loaded on the eec (firmware load from the factory).  IF for some reason the car is running oddly, or needs to react to a problem, it will defer to a generic "limp mode" table and run on an established baseline timing but it does effect fuel economey and emissions.



Info on your TPS.................
tps test throttle position sensor
1 location-- vertical mounted on pass side of CFI with org/blk/grn wires.
Probe the green wire with positive lead of a meter and ground out
the black lead of your meter.

2 turn ign sw on ,, no start

3 the voltage reading on your meter should be around .5-.9 vdc.

4 operate the throttle linkage very very very slowly and note increase in voltage. Your increase should be smooth with no jumping and it should top out at around 4.6 vdc.

notes..
It is best to use an buttstuffog (needle type) meter when doing this step because it will detect flat or open spots on the variable resiseter (tps) better than the digital types.
you can bench test the tps buy hooking up to the green and black then black to org and measuring resistance and the two readings should match. The green wire is the center tap of the variable resistor. The resistance reading will be proportional to what you see in dc volts.

if you find your low end voltage is at or above one volt,, use a chainsaw file to file out the mounting holes so that you can mount and adjust the tps CCw to achieve the "less than a volt" goal.

when installing the tps,, lay it in place but slightly clockwise,, seat the tps then rotate it ccw to line up the mounting screws. There is a little pin up in the likage that will put your tps in a bind if you dont do this correctly. You cant just lay it on and bolt it down any old way.


Info on your fuel pump and stuff.....
Fuel pump testing (intermittant or no pump sound)
(references are made to a schematic but are not shown,,leme know if you need em)

*******NOTE*******
1983 and 1984 model owners listen up!!
Some cars got two pumps. One low presure electric pump in the tank and a high presure pump near the fuel filter. Make sure you know what you have and verify you have one or two.

later models got one single high presure pump in the tank and im sure most cars with two pumps could delet the external one for a single in tank version.

I could suggest what the Shop manual says to do and it might be in your best interest to do so cause it will verify if the pump is actually going bad or not. They say to install a fuel pres tester to the shrader valve and secure the guage to the windshield with tape. Drive your car and observe the fuel presure does not drop below 30psi during the "LABOR" of the engine between shifts. If it does fall below, replacement is gonna have to happen. Driving the car under a load is really the only way to simulate the problem.

I does sound like an electrical issue but here are a couple diagrams to help out. Primary page to focus on is page 54. Page 55 shows that power splice "s532" on the top and is the source or "source splice" of power for your fuel pump relay located at lower right hand front of engine.

Go to the test connector and ground out the tan/light green wire.
turn the ign switch on, this supplies power energize the EEC Relay.
The eec relay will now deliver power to the coil of the Fuel pump relay. (stare at it for a min and you'll see what i mean)
the fuel pump relay will get its ground from the eec.
the pump relay will energize if the inertia sw is closed and the eec pin 22 supplies the ground.

The fp relay yellow fuse link wire will send power to the pump directly if all works as planned.

Your best hope is that the fp is not working while you troubleshoot. This way you can isolate the issue without even getting dirty.
Perhaps checking the fuse link connections up at the starter relay would also be an option while troubleshooting.


With the tan/light green wire grounded and the ign sw on, you can hear the pump run.
If you do not hear the pump run,, ground out the same color wire at the relay in the trunk.
if the pump does run, the eec or the chassis wiring (tan/lg)leading to the relay is defective.
If it does not run still, then apply a 12v power leg to the pink/black
if the fp runs, the relay is defective.
if the fp does not run, its the pump.



Info on your fuel injectors and how to clean.........
fuel injector id
Per the '87 Ford Emissions manual the '84-'87 3.8 CFI uses a green top 37lb inj. The std 5.0 CFI got 46lb blue top inj. while the HO 5.0('84-'85 Mustang automatics)got a grey top 52lb inj. --- by turbocoupe50

fuel injector cleaning...........
remove the cfi from intake
split the cfi in half via three phillups bolts from the bottom.
,, removed the lower injector retainer (be careful on the screw or you will be taping a new hole).

gently pull the injector out (keep track of your smaller orings).

take a pointed tip screw start this screw into the brass bushing just at the top of the injector until it started to grab real good.

grab the screw with pliers and pulled real hard and out pops the injector screen that is molded to the brass bushing.

spray the injector screen assy down with starting fluid or something.

Next, blast it with the air compressor.

insert the screen assy back into the top of the injectors,, turn the injector upside down and tap it on the workbench which will seat the brass bushing part back in its seat.

re-install the injectors and man does make a difference.

the screen assy is only about a half inch long and about 3/16 in diameter. Pretty fragile looking also. I re-shaped the screen on one becase it was a bit sucked together. I re-shaped it with a small ink pen insert.


timing chain slack measure......................
a breaker bar, extention, socket is needed.
rotate the crank the OPPOSITE direction it spins while running.
rotate it until your harmonic lines up with ZERO deg TDC
you have to be exact on where you stop so make sure its at zero.
now, move the crank the the normal running direction very slowly
this should be kind of where the easy / sweet spot is.
continue moving the crank in the normal rotating direction slowly!!!
suddenly it will get hard to move and you must have a good feel for it!!!
this is the stop / go no further point!!!
thats where the rotor button should start to move if you have the dist cover off.
now,, look at the timing indicator and the harmonic
jot down the number on the harmonic that the pointer is telling you.
repeat the test a few times then average them up for the final slop reading.

My car had 300k and the slack was present for 2/3 of that time so these 3.8's
can take some abuse so its up to you.
i dont know what is good or bad,,,just voice what you have found and
determine if you need a new chain/gear set or not.



Various sensors and how to test them...........................
=============================
EGR/emissions solenoids (codes)
Dual Thermactor Air control Solenoid Valve- both should read 51-108 ohms
EGR Solenoid Vacuum Valve Assembly - both should read 32 to 64 ohms
EGR Valve Position Sensor EVP (OR/W to brn/ltgrn resistance is 5.5k with no vac and 100ohms with vac)(4-6vdc on VREF or/wht)
Electronic Vacuum Regulator EVR 30 to 70 ohms (koeo voltage is about 10.5vdc)

============================\
EGR test and EVP sensor test
apply vac pres to egr vac line fitting.
if it holds the diaphram for a long time,, the diaphram is good
remove carbon buildup on egr base as well as egr base plate assy for 3.8l engines

EVP test (egr sensor)
wire id...
EEC PIN 26 "VREF" orange/white (parallels off to map)
EEC PIN 27 "EVP SIGNAL" brown/light green
EEC PIN 46 "SIG Return" black/white (parallels off to self test conn)

disconnect vac line
disconnect elec conn
hook ohm meter up to the VREF adn EVP Sig contacts
hook up vac guage or apply vac to egr
ohm meter should start out at about 5.5k ohms.
as vac is increased to max, resistance should bottom out to no less than 100ohms.

key on, engine off
cap off vac fitting on evp sensor
measure for 4 to 6 volts dc between VREF and SIGNAL RETURN (ground)
______________________________
ECT sensor test feeds the computer
Resistance test pin to pin of the sensor (this is a variable resister proportional to temperature including outside air temp if the motor is cold)
at 50degF=58K ohms
at 65degF=40K ohms
at 180degF=3.6K ohms
at 220degF=1.8K ohms

next clean the end of the sensor with scotch brite ect and retest
if high temps persist, replace coolant temp sensor and ECT as a matched set.
if that does not work, start looking at your coolant system parts.
----------------------
ACT sensor test ,,,feeds the computer
Resistance test pin to pin of the sensor (this is a variable resister proportional to temperature including outside air temp if the motor is cold)
at 50degF=58K ohms
at 65degF=40K ohms
at 180degF=3.6K ohms
at 220degF=1.8K ohms

Map sensor check,,,,,,,,,,,,,,,,,,,EEC IV only but it may help you
Apply vac pres of about 15lbs to the map, if it holds vac, move on to next step

Key on engine off test
map sensor signal output is the DB/LG wire
**compare output of like maps and average thier outputs if possible per the shop manual
**your altitude is proportional to the barometric presure which the map works off of.

altitude in ft / voltage
0-----------------1.59
1000--------------1.56
2000--------------1.53
3000--------------1.50
4000--------------1.47
5000--------------1.44
6000--------------1.41
7000--------------1.39

If output is in range compared to other maps the move on

Plug off map vac line
apply a few lbs vac to map, like 5 to 8
start engine
slowly apply 15lbs vac and hold about 1500 rpm
while in this test, run the KOER quick test
are any map codes present? (ie-22) if no, then your problem is not the map, its another vac related issue.

I thought about this too, given the car's weirdness due to the hillbillies. Sometime after that initial post though I found a BOSCH part number list and the injectors are indeed 5.0 CFI application, 5.81 gm/s. My guess is that the color is just very faded and looks green. (Seriously, it looks like the same color as the ones on my 3.8L CFI, but the part numbers are different. The injectors off the 3.8L have the BOSCH number for the 3.8L application and the ones off the 5.0 have the number for the 5.0L application.) I do have a second set of the 5.0L CFI injectors (in a previous post I mentioned a mechanic friend who gave me a throttle body from an 85 5.0L) and I might try those if I can get this bird running in the first place. I know it was running with those injectors, so I have no reason to swap them out yet.

Also, I know I have the right TB because the size of the holes on the intake match the size of the holes on the TB perfectly.


I have that too and my 85 TB also has the vacuum fast idle kickdown. That system has given me nothing but trouble. It messes up trying to adjust stuff. I'll adjust something only to discover that the cam on the choke was forcing the throttle open way to far during the adjustment. It also has a tendency to get stuck on the 3rd highest cam. I seriously think that the first time I went in to smog the idle rpm was so high because the choke was stuck!


ZOMG! EPIC! ...no, I had no idea, but that's cool.


Okay, but won't that be somewhat dependent on my idle speed setting? So I'll have to adjust that every time I do an idle speed adjustment right?

Yes, softouch has been extremely helpful! :D The DS3 alignment info was some fo the best I've come across so far and cleared up a lot of confusion for me.


Good to know. It was kind of tempting as I do have a bunch of extra multiport injectors.


My guess is that the diaphragm collapsed in such a way that it sealed off the vacuum passage. Also I've noticed that these CFI cars seem to be able to handle a vacuum leak a lot better than EFI cars. Don't know why, but this car was able to run with only a little bit of trouble with a fair size vacuum leak, while my van (4.0 EFI) with a smaller vacuum leak can't even idle.


Actually it's different for the EEC-III. Because the EEC-III uses a 9 volt reference instead of a 5 volt (like the EEC-IV), the correct voltage is nearly double (about 1.6 to 2.2 V). Also, the TPS on the EEC-III (or at least on this one) is not adjustable. I'm reading about 1.8 V off of my TPS with closed throttle, so I should be good on that front.


I think I have two pumps, but I'm not sure. I do hear a pump come on when I turn on the key and the fuel pressure at the throttle body shrader valve is 39 psi and constant. I also see fuel squirting out of the injectors while cranking, so I think my fuel delivery is working just fine.


lol. Silly EEC-III, test connectors are for REAL engine control systems! That being said, I do have a sort of test connector. It has three wires in it, two are the TAD/TAB solenoids and one is ground or something. I use it to read codes so I don't have to take the coolant overflow reservoir off. (EEC-III has no OBD so I only have some limited KOER capability).


Fusable links (all the ones I could find anyway) are all good. Did a resistance test on them (and all the other wires) while I had the harness out.


This is pretty much all EEC-IV stuff. The EEC-III uses a different reference voltage and so the outputs are different. I'm assuming (for now), due to lack of available information, that the RESISTANCE values of the various sensors (EVP, ECT, ACT) are the same for both EEC-III and IV. It makes sense to me that Ford would just keep using the same sensors until they ran out of their inventory.

Now that I'm done responding, here's some updates to the continuing saga:

Somebody, probably my dad, mentioned the neutral start switch. I initially dismissed this as I am getting power to everything and the car does crank and sometimes run for a second. BUT! Having nothing else to do I decided to strip my ignition circuit of "non-essentials" and check my voltages as I removed each extra component in the circuit. Fortunately there were really only two things: the neutral start switch and the instrument cluster. Disconnecting the instrument cluster improved my voltage to the ignition module, coil and EEC power relay in "run", but didn't do much for me in "start". Bypassing the neutral start switch however, oh boy, I gained a whole VOLT of power going to the coil and ignition module in "start" ("run" voltages stayed mostly the same). Spark quality also improved (now is a blue arc, but my dad says it still isn't as bright as it should be), but the car still won't start. So, though I was getting power through the neutral start switch, perhaps the switch is partially closed or wearing out and has a lot of resistance to it?

Even so, I don't think this is my main problem, and I'm certainly not going to pass smog without my instrument cluster. What about the alternator and voltage regulator? Can they cause this kind of "starts but won't run" behavior?

those were just quotes from my diy link,, could've been helpful to you if you needed it.

did you notice the part where you do a fuel pump test while driving the car?

you can never ever get a good test with the car just sitting there at idle or even in gear and braking, gotta drive it and watch the pres between gears, nothing lower than 20psi is allowed at highest point / rpm of each gear in my opinion.  I am not saying this is your problem, just letting you know.

It still sounds iike your car is runnng in limp mode after you so called "reset the computer".

Some voltage and resistance checks from the 84 shop manual.
Coil resistance:
Disconnect the coil connector.
The primary resistance from the Batt to the Tach terminal should be 0.8 to 1.6 ohms.
The secondary resistance from the Batt to the high voltage terminal should be 7,700 to 10,500 ohms.

Ballest resistor:
Disconnect the coil connector and the two wire connector to the ignition module.
The resistance between the module cable connector that goes to the red wire and the batt terminal of the coil connector. It should be 0.8 to 1.6 ohms.

Coil voltage should be 6 to 8 volts on the Batt side of the coil with the ignition in run.

The green wire to the ignition module should be greater than 1.5 volts with the ignition in run. Measure by pushing a pin into the wire.

I don't think it is, but it's always possible. I "reset the computer" by disconnecting the battery for a couple hours. Usually having no power for a while clears it. At least that's how it's done on my EEC-IV cars.
 

Those are the same as in my 1983 shop manual. Everything tests fine... well... until today....................(see below)
 

(BTW, I've now bookmarked that DIY link. Good stuff in there.) It was THIS post that led me to the solution of my current no start problem.....but you guys are going to hate me when I tell you want it was.....
 
Last night I was sulking in the garage, staring at the car, when I remembered jcassity's post about the fuel pumps and fuel pressure. I'd already checked the fuel pressure before several times while trying to solve the surging and it tested fine, (and I couldn't drive it around at the moment, obviously), but I hadn't done a pressure test since this no start problem began!
 
Normally that would be first thing after checking the ignition system, but since I saw the injectors pushing out fuel and I had done a test not too long ago (and recently replaced the pressure regulator) I didn't think it would help. My dad came into the garage, saw me attaching the pressure gauge and tried to talk me out of it, saying it was a "waste of time" for the reasons I just listed. But I hooked it up anyway and turned on the key and ... nothing... A paultry 3 PSI. I switched it on and off several times and the most pressure that built up was 4 PSI.
 
I have to tell you guys: I've never been more excited in my life to have low fuel pressure!
 
Finally! Something I can DO!
 
Now for the best bit: It's definitely the pumps.
 
I disconnected the fuel line ahead of the in-line high pressure pump and I removed the pump relay. I attached a piece of fuel line to the high pressure pump with the other end leading into a measuring cup (capacity of about a liter). I jumpered the fuel pump relay to give battery power directly to the pumps for about 10 seconds and then checked how much fuel went into the measuring cup. (Basic volume test.)
 
PRACTICALLY NOTHING. About 10 mL. I did the volume test several times, it kept giving me nothing, and then suddenly it just started pumping out fuel like there was no tomorrow. I hooked the fuel line to the TB back up and tried to start the car. It fired right up and ran GREAT! Fuel pressure was about 41 PSI. I let it run for a little, while watching the fuel pressure and waited. Suddenly the pressure started to drop and the car started to struggle at a little under 30 PSI. I turned it off and the pressure stopped dropping. That was a couple hours ago and the pressure is still holding.
 
My pressure regulator is still good which means I'm not leaking fuel through it into my return line, which means it's an intermittent problem with one or both of the pumps. Now, I'm not going to say that new pumps will solve my surging, because there's no way to verify that yet, but it WILL solve my no start.
 
That being said I'm looking for some new pumps. I'm thinking of replacing the two pump system with a single high pressure in-tank pump. Right now I'm looking at this High Flow Performance pump: http://highflowfuel.com/i-5210331-hfp-255lph-fuel-pump-ford-thunderbird-1983-1997.html
 
I feel like if I'm going to go through the bother of dropping the tank I should put in a quality pump that will support any modifications I decide to make to the car down the road (such as SEFI, H.O. CFI, or whatever). AND I want to use just one pump, in-tank, just in case I ever add a dual exhaust. (I'm figuring save time and money later.)
 
Has anyone used a high flow pump (255 lph is WAY higher than the stock 66 lph) on a stock CFI setup? I don't really see it as being an issue, but I don't want to kill my pressure regulator or new pump due to ignorance.
 
Special thanks to jcassity and softtouch, thank you for coming on this wild goose chase with me. If you guys are ever in northern CA, I owe you lunch or something. Hopefully when I fire it up with a new pump everything will work perfectly with no surge (fingers crossed).

Thought everyone should know the final verdict:

The cause of the surging was the ignition module.

With it running I was able to diagnose it. Put the old module in, idle surging, put the new module in, no idle surging.

With the new module it idles smoothly, exactly where I set it and where CA wants it. The spark advance timing adjustments made by the EEC are a lot smoother too. Before I would watch the timing and it would kind of waver around (it'd fluctuate erratically +/-3 degrees). Now it holds steady and doesn't move until I rev the engine or change gear. When it does change it is a smooth adjustment. So, for the future, if your checking the timing and your mark is moving erratically (looking like it's "vibrating" a bit is normal because of the strobe effect from the timing light) you should check over the whole ignition system. Of course, none of my tests showed there to be anything really wrong with the ignition module, that was just an act of desperation on my part.

Btw jcassity, I'm going to go by the Ford dealer soon and see if I can convince them to look something up for me. I have two stock CA 5.0 throttle bodies with green injectors. One of them I got from a guy who is one of the best mechanics I've ever known and he said that the whole TB was stock, never messed with. He got it ages ago, shelved it for years, and then gave it to me. I'll bet you that CA required Ford to put green top injectors on the CA 5.0s, that's what I'm going to try to find out. I hate this state.

Thanks for the feedback.

good news!

ive never seen green top injectors with the same pn as the blue tops, however, this was in the early stages of this body and car design.  Ford does tend to change things too often to my liking.

Wow, since I've been away from here for awhile I have a lot of catching up to do!  It's great there's been so much information on this subject..thanks to all who helped out.:bowdown:

This is good news, especially since I bought an ignition module recently in order to see if this would fix the surging issue on my 83. In the past I just increased the idle speed when it occurred but not a great fix since it required increasing to the point where I needed to keep my foot on the brake at 'idle'.:hick:

As soon as I get time, I'll fire up my 83 and if it decides to surge I'll have the new ignition module handy and ready to swap to confirm the fix.

So, I spoke to "my local Ford dealer" about the injectors. The girl behind the parts counter said that the 5.0L CFI injectors for the "CA/NY emissions application" are DIFFERENT than those for the rest of the U.S.

She e-mailed Ford HQ to confirm if a "green top" injector was used on the CA 5.0L engines stock and to see if these are the same as the 3.8L injectors (which are also a different part number). She says she'll give me a call when she hears back from them.

THE PLOT THICKENS.

I hope it helps! Of course, just cuz it worked for me doesn't mean it'll fix every EEC-III CFI with an idle surge out there.

I'd say take a look at your timing marks and if they are erratic and jumping around like I described before, there's a good chance a new module will help out.

I would say to follow the following troubleshooting guide:

1) Test all sensors, solenoids and switches (relays). The three 'S's.
2) Check all vacuum components for leaks, including lines.
3) Test continuity and check for shorts/crossover on all sensor and solenoid wires between the components and the EEC.
4) Test the ENTIRE ignition circuit, including coil and plug wires. Do a spark test and make sure the module is getting the appropriate amount of power at the right times and that it is capable of acting on a "spark" signal from the EEC (the orange wire).
5) Check your distributor cap and rotor and rotor alignment.
6) Fuel system tests. Do both a pressure test at the throttle body and a volume test of both pumps, together AND individually. If you get volume, but no pressure, you probably have a bad regulator, but a bad check valve in your fuel pumps is also possible. After the car is off, the pressure at the TB should be held for a pretty long while (my regulator took a couple days to drop to 35). Also check for any kinks in the lines and replace the fuel filter. Clean the injectors.
7) Pull codes from the EEC-III. (I'll post more on my adventures in that happy land later, as I want to go to bed.) Fix whatever it's complaining about, if anything, then repeat this whole process. If it doesn't complain about anything (code 1-1 or no codes) then it could be the EEC module itself. The EEC-III has separate circuits inside the module for different tasks. For example, each solenoid has a different circuit. If you did something stupid while playing with one of the solenoids you'll damage that solenoid's circuit inside the EEC module. The car will still run and the EEC will still do other stuff, but, for example, if you damage the EGR solenoid circuit then the EEC will not be able to open and close the EGR causing you to fail your smog test. This kind of failure will also not give you a code, because the circuit is unavailable to generate the code in the first place. (WARNING: this is all according to some stuff I read, I forget where, but it makes sense if you think about it. I'll try to verify it somehow.)
8) Rinse.
9) Repeat.
Results may vary. Ask your doctor before using. Common side effects are frustration, skinned knuckles, headache, and loss of brain cells due to exposure to gasoline fumes.

This all assumes that your base timing (cam to crank, set when you first put the cam in and align the timing gears!) is correct, and that the lobes on the inductive ring on the harmonic balancer are still intact and in the correct spot relative to the crank position sensor (one lobe directly under the CPS at 10 degrees BTDC).

ANOTHER THING YOU CAN CHECK is your exhaust system. Make sure the cats or the ler are not partially clogged. Check the weird heat control valve on the left exhaust manifold (if it's stuck closed, you got problems). Clean out all carbon, "far as the curse is found".

I'll add more to this later.

Great information!

Here's something interesting I found in the Ford "EECIII EECIV Training Program Reference Book"

[COLOR="blue"]=>Microprocessors

==>Engine Idle Speed

Another system, not normally associated with emissions, is engine idle speed control. Since carburetor air/fuel ratios have been leaned to a point where the engine would idle smoothly at higher engine speeds due to emissions, the ECA controls the engine idle speed. The ECA increases the idle speed but, upon engine shutdown, the idle speed is immediately decreased by the ECA.[/COLOR]

This confirms the ECA controls the idle speed and that there is a function to increase and decrease (surge?) the idle based on some input.

Sounds like this circuitry could be the cause of surge.

crossalchemist,

I came across this thread while searching the web for symptoms and solutions for my temperamental CFI 302 equipped Mercury Colony Park. The vacuum diaphragm in my fast idle was shot and I can't find where to buy a replacement diaphragm. Where did you get yours? Any help from other forum members would also be appreciated.

My 1984 Ford Thunderbird 5.0 date of manufacturer is 12-83 has a Distributor WITHOUT an Ignition Control Module TFI mounted to the distributor. It has an Airtex 6H1104 Ignition Control Module (shown in the link) mounted on the driver's side inner fender panel and has a Ford Distributor part number E2AE-12127-GA which never had a place to mount a TFI module.

I still have the common idle surge miss for this year and wonder which 1984 Thunderbird 5.0 models changed distributors and why the car idles rougher sometimes. The car has only around 70k original miles and has some oil blowby from the oil cap but no smoke out the exhaust and doesn't use much oil.

http://www.stockwiseauto.com/product_info.php/products_id/228760/fit_id/5111/Year/1984/Make/Ford/Model/Thunderbird?gclid=CIvG5OH1scACFQ5rfgodtZAAdw

Any knowledge on this.

Intermittently runs different, not as smooth at idle and has a hiccup miss sometimes after a minute of idling.