Just installed new injectors an now car idols rough

Topic: Just installed new injectors an now car idols rough (Read 4228 times) previous topic - next topic

Just installed new injectors an now car idols rough

Reply #15 – February 13, 2013, 06:10:29 PM

Quote from: 86TBIRD;409280

What mods u run to get the 30+ mpg

At the time that I started monitoring this, I was on a stock motor with HO upper intake, and maybe throttle body. The motor was tired with over 200k miles and maintenance neglect (there was a 3/4-1 inch layer of hard carbon in the lifter valley when I took it apart). After I installed an electric fan, I saw a 1 to 1.5-ish mpg gain on the highway (average). There's a thread on here somewhere from my testing on that morning.

I think I was around 30mpg at 70-75mph and 32-33mpg at 60mph, then the electric fan got me up to 34.5mpg at 60mph (the testing was something like 30mpg one direction, 38mpg on the way back). My fuel economy on the highway didn't change much at all after rebuilding the motor and using gt40 heads, full exhaust, etc and a 4r70w. Going from 2.73 gears to 3.55 dropped me down to 26-27mph. Switching to 3.08s got me back to 30-31 and I got traction with stock sized tires on the 1-2 shift on summer days. I had to let up on the throttle to get traction back when I was using the 3.55's and hitting the 2nd gear shift. It wasn't the power or tires so much as it was due to me running aggressive transmission fluid pressures in my 4r70w transmission (and the additional gearing in 1st and 2nd over the AOD). Oh, I think bumping the tire pressure up to 40psi also helped me on those tires - it was likely around 1mpg on the highway. I was making a lot of 140-mile trips every weekend back then and using 4.1-4.3 gallons each way. I'd normally be between 4.2-4.3 gallons used at that point. I calculated my numbers off of a tripminder, which matched the fillup numbers. I used GPS data for the mileage as the car reads a bit low (by 4%). I have the "correct" speedo gear in there, but I just need to bump it up by the next size which will be slightly more accurate. Since I am no longer even close stock, the best way I can get close to my old numbers is by pulse and glide - allowing the car to accelerate in 4th gear, then letting off the gas completely. With my mods and tune, when I am over 30mph and the throttle is closed, the engine basically shuts off. This has allowed me to get close to 33mpg with my current parts, but it isn't really something that someone wants to do all the time unless they are a "hypermiler".

If you have the stock motor, I'd check to make sure that your oxygen sensors are good, you have good spark plugs, wires, coil, rotor cap, etc, have a good alignment. Check/replace wheel bearings, transmission fluid, and other drivetrain items. Something is really wrong somewhere if your motor is stock but you have trouble reaching at least 20 city/30 highway while not slamming down the gas pedal between every light. You will have a slightly higher aerodynamic disadvantage due to your non-aero frontend, but it shouldn't impact it TOO much.

Just installed new injectors an now car idols rough

Reply #16 – February 13, 2013, 07:56:16 PM

Well I just replaced 85 % of the things u listed I still need the wheel bearings an o2 sencers but I like the idea of the HO intake I think that's what I'm going to do HO intake an stock injectors
An on a side not u have any Idea what makes the digital speedo to dim cuz I can just barely see it

Just installed new injectors an now car idols rough

Reply #17 – February 13, 2013, 08:25:10 PM

Sitting on my shelf collecting dust??

Just installed new injectors an now car idols rough

Reply #18 – February 13, 2013, 09:52:21 PM

Keep your e6 heads, and throttle body, get a sd computer, 19/lb injectors, swap in a h.o cam, and have yourself a mock 86 mustang engine. When the car needs exhaust, throw on duels.

I'll bet this would get you 90% of what your looking for.

Just installed new injectors an now car idols rough

Reply #19 – February 13, 2013, 10:25:00 PM

@Tom
Thanks for the offer but I already have a HO intake an yes they are grey injectors
But what year that intake come on? An what model thanks

Here a pix of the old bird I've owned it since I was 15 love this old car an hate to see what it's become since I let it set so long needs a lot of love but I hope to have her back showroom ready someday

Just installed new injectors an now car idols rough

Reply #20 – February 14, 2013, 01:19:19 PM

The HO intake will certainly help all around with the stock longblock. You might also want to look into adjusting the tv cable and replacing the grommet that holds the thing in place. While more HO engine parts would help performance, getting the stock motor running well would need a better flowing intake at a minimum. Headers and exhaust would help a bit too, but they're more necessary with a HO swap.

If you're just looking for a good daily driver, the stock motor is fine. Adjusting the tv cable will change how the transmission shifts and provide more pressure, which may increase longevity at the expense of being a more harsh ride (shifts won't be as smooth). Allowing the engine to shift higher in the rpms by adjusting this also means that you need to get the engine breathing a bit higher up in the rpms, which the intake and exhaust help with. I'm also of the belief that a larger tb and removing the air silencer will do about all you need on the stock motor intake-wise. The power difference IS noticeable - I remember how nice it was that the car was just that much faster. When you're working with 150hp and 270ft/lbs, a small improvement makes a big difference, especially if you can get another 500rpms out of the shift points and motor.

So how's it running right now? The stock motor should be pretty smooth, yet responsive at throttle input. There shouldn't be any hiccups. Also the smog pump and pipes can just cause a ton of grief. They were a common failure according to the receipts I have of emissions-related work. I think the TAD solenoid caused me to have issues idling when the car was new to me also - the thing would just die. At that point I didn't know what I was doing with cars and had it towed.

At idle you have high vacuum so check for vacuum leaks. Also make sure the EGR is good (not leaking), along with intake-track gaskets. Have you pulled codes to see if it reports anything? Mine never lit a light, but codes were stored.

Just installed new injectors an now car idols rough

Reply #21 – February 14, 2013, 01:25:00 PM

Quote from: 86TBIRD;409297

@Tom
Thanks for the offer but I already have a HO intake an yes they are grey injectors
But what year that intake come on? An what model thanks

Looks like a 96-98 Explorer intake. It's extremely overkill for the stock t-bird motor. Vacuum would change quite drastically at tip-in throttle. They're good intakes for the stock HO motor, and ported they work well on a street motor with 300-400hp. I'm waiting to get one back from porting that I will use on my expected 360-380hp topend rebuild. Your car won't shift much more than around 4000 rpms so unless you want to change the entire engine down the road, your existing "HO" intake is fine.

Just installed new injectors an now car idols rough

Reply #22 – February 14, 2013, 05:25:04 PM

Quote from: Seek;409339

Looks like a 96-98 Explorer intake. It's extremely overkill for the stock t-bird motor. Vacuum would change quite drastically at tip-in throttle. They're good intakes for the stock HO motor, and ported they work well on a street motor with 300-400hp. I'm waiting to get one back from porting that I will use on my expected 360-380hp topend rebuild. Your car won't shift much more than around 4000 rpms so unless you want to change the entire engine down the road, your existing "HO" intake is fine.

Huh??? Vac changes in any intake at tip-in, I can guarantee a stock SO would run fine using the 14lb inj and 60-65mm TB... Would there be a increase in power??? Probably a little but so small that you'd have to imagine the increase...

Quote from: Haystack;409294

Keep your e6 heads, and throttle body, get a sd computer, 19/lb injectors, swap in a h.o cam, and have yourself a mock 86 mustang engine. When the car needs exhaust, throw on duels.

I'll bet this would get you 90% of what your looking for.

I'd agree but the stock SO TB is only a asthmatic 50mm, the '86 HO used a 58mm TB and SO upper(at least the opening is smaller than a later HO)... With the half decent flowing Explorer intakes avail cheap, I wouldn't even consider a HO intake...

Just installed new injectors an now car idols rough

Reply #23 – February 14, 2013, 05:28:36 PM

Got y'all a update reinstalled stock injectors an now it run like S**t an I can figure out why the service light comes on when I start it but goes off after like 20 mins an it idles funny any ideas fellas

An anyone know we're this grill come from is it factory or aftermarket thanks

Just installed new injectors an now car idols rough

Reply #24 – February 14, 2013, 06:45:24 PM

Quote from: TurboCoupe50;409354

Huh??? Vac changes in any intake at tip-in, I can guarantee a stock SO would run fine using the 14lb inj and 60-65mm TB... Would there be a increase in power??? Probably a little but so small that you'd have to imagine the increase...

I'm not saying it'll change much, but the larger chamber of vacuum would simply make changes in the throttle body pull in air much faster. I have no clue how miniscule this would change how the engine runs for that split second, but it'd an interesting thought. I love how much a simple sensor such as a MAF sensor makes life so much more predictable. The 60mm tb never hurt anything for me. I think the larger intake basically made the engine run closer to ideal when cold and under WOT. I have no idea what the stock EEC commands, but if it's anything like the mass air ones, it's 11.7:1 AFR. If the bigger intake track allows more air in than the EEC knows about, it will get closer to the ideal 12.5-13.0:1 AFR and make more power. I assume that is where most of the power gains come from by the swap on the stock motors. Changing how the AOD shifts with the tv cable and making more usable power up top is nice too. It would be interesting, but nothing more, to see a wideband and the changes it shows with a simple upper intake and tb change.

Quote from: 86TBIRD;409355

Got y'all a update reinstalled stock injectors an now it run like S**t an I can figure out why the service light comes on when I start it but goes off after like 20 mins an it idles funny any ideas fellas

What rpm does your car want to idle at now and before the injector change? The extra (unmetered) fuel going in could have helped it run smoother by making up for air that is getting in some place else. It is difficult to troubleshoot without being there and seeing the engine in person. It could be a bad throttle position sensor giving you bogus throttle position readings, it could be the idle air control valve that is leaking or stuck open, it could be vacuum leaks, it could be a bap sensor telling the eec that you're at a higher elevation, it could be an air charge temperature sensor or coolant temperature sensors telling the eec that the engine is up to operating temperature, etc. It could be a bad fuel pressure regulator. It could simply be a bad connector in the wiring harness or badly clogged injectors. How old is the gas in the tank?

If check engine is coming on, you need to pull codes and see what it says. It sounds like something is bad that the eec relies on when the engine is cold. Codes, even with how few there are in the EEC-IV, are very helpful.

Just installed new injectors an now car idols rough

Reply #25 – February 14, 2013, 07:55:29 PM

I just replaced all the vac lines an I'm not sure what it idled befor I installed the 21lb injectors the car an i have no idea what it idles at now dont have a tach on it, but the car hadn't been started in over 8 years I dropped the tank an installed new sending unit an replaced fuel filter oh an also cleaned tank an put fresh unethonal 93 octane fuel an it idled great but sucked way to much fuel but I think it's one of the sensors I got a friend who is going to check the codes but I believe I'm going to convert it to MAF I got a friend of is giving me two MAF computers an a MAF sensor all ill need is the wireing harness an install that HO intake

Just installed new injectors an now car idols rough

Reply #26 – February 14, 2013, 08:34:07 PM

You may have a bad fuel pressure regulator, pull it's vac line to see if it's wet... If that's OK would be a good idea to check pressure...

BTW if the MAP sensor has vac or electrical issues, it'll run 3x pig rich...

Just installed new injectors an now car idols rough

Reply #27 – February 14, 2013, 09:02:05 PM

Ok I'll try that

Just installed new injectors an now car idols rough

Reply #28 – February 14, 2013, 09:28:57 PM

Before you ever change parts by guessing, always pull codes. That will help narrow down issues and make it easier to resolve those issues.

And your grille looks like it's one of the rare Motorsport parts...take care of it, those things just aren't very common.

Describe the idle, does it hunt, go up and down, or is really low, or fast? It's sort of uncommon for injectors to really be an issue, not saying it doesn't happen, but it's not the most usual thing.
Check codes, make sure your timing is set right (unplug the spout first, it's the grey plug-like thing in the TFI harness that goes to the distributor).

And, you haven't turned the stop screw on the throttle body have you? That will wreak havoc on the IAC's settings. Don't ask how I found THAT out, ages ago...

Just installed new injectors an now car idols rough

Reply #29 – February 15, 2013, 11:48:57 AM

Ok the idle is choppy the motor shakes horrible even runing up the road I'm wondering if those big injectors messed up my fuel press regulator that what It seems to eather to be starving or running rich like it can seem to find its happy medium