I finally managed to get my Cougar home. It's a 1987 Mercury Cougar XR7, factory 5.0 SO and all that jazz. The engine was pulled and replaced with a low mileage 5.0 from the same year car. Everything on the engine was replaced, Timing chain, plugs, plug wires, all the gaskets except head gaskets...etc. The only thing that wasn't messed with are the air/fuel electronics on the inkate manifold. Like the IAC, MAP sensor and TPS. All the vacuum lines are attached and the car runs very good....most of the time. However sometimes when I am out driving it will randomly start running rough. Almost like its running lean and almost dies. Then it will stop and continue running perfectly? Not sure what the cause of it is. Hopefully you guys can help me straighten this out. If you need anymore info let me know.
Peace,
Dan W.
Try replacing the MAP sensor, it could be going bad...
Better yet; pull codes so you're not just throwing parts at a problem that has not been diagnosed.
My Saturn started doing this after I filled up at a rural gas station. The tank was full of water. I drained a half gallon or so out of it...
Im not too concerned about spending money on it. The car has been sitting for a few years so Im sure all those bits need to be replaced anyway. I'll pick up that MAP sensor tomorrow. BTW I will try to get some pics of her soon too, Thanks.
I haven't had a single map sensor go on me yet, at there near $80 new. I would pull codes. Your just gonna waste time and money. Also, what kind of shape are the vacuum lines in?
X2... Never seen a bad MAP sensor...
i had a bad one once......had a broke motor mount and got on it hard enough to break the nipple off....my hose is connected straight to the engine as i am not running the vacuum tree....
As per recommendation I checked all the vacuum lines and they look fine. I also tried disconnecting the MAP sensor, but that made things worse so I don't think its that. Then I tried to pull codes only to find my check engine light doesn't work. Running out of things to try, I unplugged the IAC. After that I took her around town for a bit and she never once bogged down or acted like she was gonna die. Any thoughts on this?
Many stored codes will NOT trip the check engine light -- even when it is working as it should.
Just a suggestion: Invest in a vacuum gauge. It'll be a wisely spent $25.
Take the iac off and clean it well with carb cleaner and put a new mounting gasket back on it ?
http://therangerstation.com/tech_library/OBD_I.html
http://therangerstation.com/tech_library/2digitcodes.html
All you need is a paper clip and a test light, or if your check engine light works, you can do that.
I grabbed a test light before I got home. I'll check it tomorrow and let ya'll know whats up. Thanks
were all here to help when it is needed.
i'm rough on my car....
c4 with a full manual transbrake valvebody will be going in soon......
So i ran that test and it came up with code 22 for KOEO and CM.
Peace,
Dan W.
MAP sensor frequency out of specs.
So you guys think I should replace it? Tomorrow I'm gonna try a KOER test.
Yep now that you've verified it has a MAP sensor related code you can repl it...
Just make sure the car is warmed up first otherwise you may get some false codes.
I ran the codes not too long after I got home from work so the car was plenty warm. I'll be sure to go over my vacuum lines one more time and then go grab that sensor. Thank for the help guys, if anything else comes up I'll be sure to let you know.
Peace,
Dan W.
I still think it could be the MAP sensor vacuum hose. I would just get a new one and try sticking it onto the air ride nipple on the vacuum tree, then run it again to see what happends. If you do this, plug up the hose that was on the map sensor, then get it warm and try the codes again.
I actually just ran the KOER test just a little bit ago and it threw codes 94, 44 and 33. All of which are related to emissions and I don't imagine they would be causing me the problems I am having. The vacuum line running from the MAP to the manifold was replaced by my father. I double checked it again and it looked fine. I'll gladly try your suggestion later to see what happens but I really think its the sensor. The only thing the car does when its unplugged it idle down a little. It doesn't really run any differently.
Peace,
Dan W.
You can yank out all the vac hoses and toss em into the street, it won't cause a KOEO for the MAP sensor...
And on that note, I'll go grab a new MAP sensor tomorrow. Thanks TurboCoupe.
Peace,
Dan W.
Got the MAP sensor installed and messed with the timing and bit. Man that thing really runs now. No hesitation or anything, it just goes when you give it gas. Thanks a million guys.
Peace,
Dan W.
Ok I'm bring this thread back ya'll. After driving that car around for a while with the timing advanced a bit, it did run better but still occasionally misses. We had some last minute adjustments to the Cougar over the weekend and set the timing back a bit to get the idle down. Now the hesitation is back just like before, still coming and going as it pleases. Just took the time to triple check all of the vacuum lines and they are all great. Replaces the PCV valve and looked over my electrical connects. So as I stand...I'm stumped. I can't explain the miss or hesitation. Even if I advance the timing it will increase the idle but a slight miss still rears its ugly head. Any thoughts? Maybe a sticking fuel pressure regulator? another electrical problem perhaps?
Peace,
Dan W.
Check your EGR valve for crud. Might be sticking open.
EGR is actually not hooked up. It was my fathers doing, not my choice. I think the only thing not hooked up is the vacuum line going to the top of it. All the electrics are plugged in. I've been wondering if that was going to cause a problem.
Peace,
Dan W.
Have you run codes again to see if it has any new ones???
The '93 Grand Marquis gave me a fit last spring with a on/off miss... Turned out to be a bad spark plug and they weren't even 6mo old... Can't say it hesitated(does that when the MAF meter gets dirty), but sometimes it ran so poorly, you'd almost think it was going to quit...
It shouldn't cause a problem if its disconnected, unless it was already gummed up when disconnected. Hopefully the vac is capped off on the engine side.
I tried running codes again the other day and I got 22 again. Even though I just replaced it. As for the vacuum lines, no the one leading EGR plate is not blocked off. The vacuum diagram is missing from my car, are there any other lines I might have missed that go to the EGR valve. Again not my doing my father was the one that did it even though I told him to hook it up. But he did mention when the EGR valve was hooked up that it ran worse? Possibly clogged you think?
Peace,
Dan W.
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look?
how about test them. unplug / cap one end and put suction on the other end one vac line at a time.
check fuel pres with the guage taped to the windshield.
check TPS with an buttstuffog meter
other than that,, replace the injector screens (most common hesitation cause imho)
I saw turbocoupe50 say that a bad vaccum line will not throw a code on the MAP sensor. I would start looking at wires. Especially where we know the car had the motor swapped out. The wires could have been pulled hard or pinched and damaged.
Unless the new map sensor is bad, I would bet on wiring. Try throwing the old one back in after you check out the wires. Your TPS sensor does now have to be adjusted. As long as it is between .76 and 1.1 volts at idle, it is fine. The computer automatically resets the value to match your highest. As long as it hits above 3.5V or so and does not have any dead spots with throttle change, it is fine.
This site here http://www.veryuseful.com/mustang/tech/engine/#Diagrams
Has diagrams that you can use for a guideline for your major vaccum lines. Your car may have more or less lines then the diagram. But most are the same.
If you think you may have a stuck injector, you can initiate a cylinder balance test while pulling codes by waiting until it starts giving you codes, you floor it all the way and then let off. It will give you codes if any cylinder fails the balance test. From my under standing, it turns the fuel injectors off and on after raising the idle to ensure the motor will not die. If you have a stuck/bad injector, it should rear its ugly head there.
Check the wires that go to and from the map sensor really good, and let us know if you find anything weird,broken, or damaged.
Is the MAP a continual fault(first test in KOEO), or is it in memory??? If it's in memory clear it and see if it returns(vac could be a issue here)... If its a continual fault, you may well have a wiring problem...
The code 22 actually showed up in KOEO and CM. I'll go double check the wiring the best I can here in a bit.
Peace,
Dan W.
Just got back inside. All the wires going to the MAP sensor look fine, as do all the other wires I could see under the hood. Tried hooking up the EGR valve and it runs pretty bad with the vacuum hooked up. But with it unhooked it runs a lot better. Unplugged the TPS and the motor revs so that seems like it works..but haven't checked if it is within parameters. Now I remember posting this before but I'll do it again. When I unplug the IAC, nothing happens. Not sure if its suppose to do that or not.
Peace,
Dan W.
If it runs py with the EGR attached, the EGR diaphram is probably ruptured.
I had the exact same problems your describing when I had really old gas in the tank. Try fresh gas and check the fuel pressure. Perhaps the FP is getting ready to go?
There was old gas in it but we got rid of it and put fresh in there. Its been running on fresh gas for quite a while now. I'll have to check the fuel pressure but I don't think the pump is the problem.
For some reason I feel I might have been describing my problem incorrectly. So I will retype it to make sure I didn't confuse anyone along the way.
On my way home just a little bit ago. I took off from a light keeping a level amount of pressure on the gas. Not too much as I am a slow driving of sorts and baby my vehicles. When it would randomly act like it either wasn't getting enough gas or air, spitting and spuddering and having no power. So I have to push harder on the gas until it stops and begins running properly. Then I can reduce the amount of pressure back to what I usually drive at. Again this doesn't happen all the time, just when it feels like. When we advanced the timing the most of the problem went away, but it would lightly act up from time to time. There is still the miss with or without the timing advanced its just less noticable when you advance it.
Hopefully that should straighten things out a bit. Sometimes I don't check over what I post and just wanted to clear up and confusion if it exists.
Peace,
Dan W.
i get it dan,, first and second time
just trying to get you to eliminate a lot of parts quckly.
add to my list,,,,,,,,,,,,,,,,,,,,,,,
at night, spray plug wires with spray bottle of water, coil area to.
look for sparks / archs jumping.
partial throttle typically points to a tps problem. one indicator would be if you "think" the problem happens when the gas pedal is in approx the same location. this consistency would point to as defined,,,"throttle position" or the sensing device
after that, i would pop the dizzy, spray down deep into the stator to clean that part off. there is a magnet in there that could be catching debris.
measure fuel pres
measure tps
plug far end of vac lines and suck on the other end and see if they hold suction
spray carb cleaner along vac lines and intake mounting areas including throttle body mounting and listen to engine rpm changes.
just for grins
rotate your crank to zero deg on the pointer.
now gently rotate the crank ccw and read what deg the pointer is pointing to on the harmonic balancer. this will tell you how much slop is in the timing chain. I might be backward on my directions but either way you will see what i mean.
Sorry, I guess I repeated someone else's post. Jcassitys timing chain slack test is a good one to try. I had an engine with a really stretched chain. When I tried to time it, the spark location would jump around unpredictably (with the spout disconnected). When I tore it down it had about an inch deflection on the timing chain. The engine had a part throttle miss like yours, it also would have an occasional idle miss and hard starting. It was a pretty tired engine and may have had other problems.
Thanks for the advice guys. I'll try some of that stuff out. I just moved to Tennessee and I'm getting settled in.
Peace,
Dan W.