Car Running Rough, Need Help.

[blackmirage]

Ok, I have a 90 Talon AWD TSI.. When I first got the car it ran REALLY bad, fixed the following. The plug wires were all out of order.. the vlave cover gasket and the spark plug gaskets on the underside of the valve cover were changed. (that took care of the oil in one of the cylinders).. then I replaced the exhaust mani gasket. removed the fuel that was sitting in ther car for about a year and replaced the fuel filter. also did an oil change and put a little lucas fuel injector cleaner in there too. After that, It still ran a LITTLE rough but not bad. however the car wont rev past 3k when idling or while driving when the maf is plugged in.. just did a boost leak test and found one of the vaccume lines to be busted and the injecotr o ring to be bad, replaced the line and the o-rings and car runs better.. but still with the maf plugged in it wont rev past 3k without it.. the car runs OK, but its still not right.. when I MASH the gas it hesitates and sputters for about 500-900 rpm then takes off. there are NO other leaks present.. I have a MAF sensor on the way, in the mean time.. can anyone think of anything else I can investigate? the car is stock, its a manual.. I dont think I have forgotten anything. Any help would be appreciated.

 

[eclipse_20g]

I'd be replacing the o2 sensors and opening up the ECU to make sure eveything looks Ok in there too while you're at it.

 

[blackmirage]

Ok, good Idea...

 

[92awddsm]

Do you have a check engine light? Has the car ever had an afc installed?

 

[blackmirage]

Never had an AFC, car is stock COMPLETELY.. Check Engine Light only comes on when the MAF is UN plugged.. wich is weird because it runs better with it UN plugged.

 

[blackmirage]

ok I replaced the 02 sensor AND the maf sensor.. It still will only run GREAT when the maf is UN plugged.. However it runs rich regardless.. I havnt checked the ecu yest, can anyone think of anything that would cause this?

 

[92awddsm]

I would suspect ecu. Pull it out and open it up for inspection. http://www.tmo.com/howto/ecu1g/checkeprom.htm

 

[blackmirage]

What would I be looking for, anything in particular??

 

[92awddsm]

What would I be looking for, anything in particular??

Look for leaking capacitors, burnt spots, or acid etching on the board around the capacitors.

This shows capacitor location and replacement procedure.

 

[blackmirage]

Ok, before tearing down into the ecu we looked at my o2 sensor and it was covered with black soot.. much like the plugs are.. so we wiped it off the o2 sensor with a rag and blew it out and put it back in.. car ran GREAT revved up past 3k with the maf plugged in and all. but only lasted to the end of the drive way.. I figured it was because it got covered again, so we tried it again and it didnt work. Does this give any further indication to what might be happening? or should I just get down into the ECU?

 

[King Salami]

Where did the soot come from on your 02 sensor?
I'd do an exhaust leak check by running some Seafoam or Mopar Combustion Chamber Cleaner through your engine. Any exhaust leaks should reveal themselves by smoke coming out of 'em.
If your plugs & 02 sensor are covered with soot, you've probably got a bunch of carbon deposits in your combustion chambers. SF & MCCC will clean it off.

 

[95talon_in_ma]

I remember an article where someone had soo much carbon buildup, it actually increased the compression to around 200+. Might want to do a compression check first. I think they used something to soak the cylinders directly, maybe seafoam...

Did you try unplugging the battery for a period of time?

I had a weird experience when I bought a Talon with a bad motor. I put my good motor in and obviously the battery was diconnected for days. Even when I put the other motor in, It ran like crap. Sputtering really bad around 4K etc.. I drove it like that for a few days, then the CEL came on. I checked everything and couldn't find anything wrong. I then unplugged my battery again for about an hour. When I plugged it back in, the CEL was gone and the thing ran like a champ. It's been several month's with no issues.... It's almost like it had to be reset twice... like there was some sort of residual memory.

Was the MAF hacked?

Good luck!

 

[blackmirage]

I'm guessing the soot is from running pic rich? Possibly.. Maf is not hacked.. never was never will be.. Whats this combustion chamber cleaner you guys are talking about... I've not heard of this before...

 

[92awddsm]

I'm guessing the soot is from running pic rich? Possibly.. Maf is not hacked.. never was never will be.. Whats this combustion chamber cleaner you guys are talking about... I've not heard of this before...

MCCC= Mopar Combustion Chamber Cleaner. It can be purchased from any chrysler dealership.

SF= Seafoam. It can be purchase from almost any auto parts store.

Another option would be automatic transmission fluid. You can remove the plugs and pour it straight into the cylinder. Allow it to soak for 24hrs and then spin the engine(with the plugs still out) to blow the excess out. This will make a very large mess so have some rags on hand. You can also suck it through a vacuum line while the engine is running and it will have the same effect as the sf or mccc, just provide more lubricity than than the previous 2.

 

[King Salami]

Be warned - Seafoam and MCCC makes gobs of smoke out your exhaust, If your neighbors are as persnickety as mine, you may want to find a empty lot or stretch of road to do it on.
Do a search for "Terry's idle surge", "MCCC", or "Seafoam" for directions on how to use this stuff.

 

[kingdaniel04]

Ok, I have a 90 Talon AWD TSI.. When I first got the car it ran REALLY bad, fixed the following. The plug wires were all out of order.. the vlave cover gasket and the spark plug gaskets on the underside of the valve cover were changed. (that took care of the oil in one of the cylinders).. then I replaced the exhaust mani gasket. removed the fuel that was sitting in ther car for about a year and replaced the fuel filter. also did an oil change and put a little lucas fuel injector cleaner in there too. After that, It still ran a LITTLE rough but not bad. however the car wont rev past 3k when idling or while driving when the maf is plugged in.. just did a boost leak test and found one of the vaccume lines to be busted and the injecotr o ring to be bad, replaced the line and the o-rings and car runs better.. but still with the maf plugged in it wont rev past 3k without it.. the car runs OK, but its still not right.. when I MASH the gas it hesitates and sputters for about 500-900 rpm then takes off. there are NO other leaks present.. I have a MAF sensor on the way, in the mean time.. can anyone think of anything else I can investigate? the car is stock, its a manual.. I dont think I have forgotten anything. Any help would be appreciated.

bro i had the same problem.my coil pack was shot and was doing exactly that...i aslo had covered o2 sensor because the car was running rich due to the sputtering-which was because the coil pack firing and not firing or firing enough u know....anyhow,those are my thought from exp...good luck bro!

 

[blackmirage]

are you serious, a friend of mine told me to check that and I blew it off. Man I wish I had tried that before I just took the ecu out and checked it.. The ecu looks beautiful NO leaking of anything.. all good there.. guess I'll price a coil pack and put the ecu back in.. Thanks for the help guys.

 

[blackmirage]

Well..........its not the coil pack! Still does the same god **** thing
I'm going to try this combustion chamber cleaner stuff and see what that does, but I honestly dont know what to do at this point. I've replaced everything I can think of. Any ideas, words of wisdom, encouragement. Anything at this point will help.

 

[blackmirage]

You guys think it could be timing?

 

[King Salami]

Since it seems to be dependent upon the MAS being plugged in, I would suspect that your fuel mixture is way off. But I don't see how it would keep you from revving past 3K. Odd.

It's worth the effort to check your timing. I would pull off the front cover and visually check that the crank & cam pulleys line up on their respective marks. Then I would check out your CAS timing w/ a timing light.

The majority of the rough running and/or knocking problems I've encountered were attributed to boost leaks, exhaust leaks, or slipped timing (happened to me twice).
If you're running pig rich, an exhaust leak may be the cause. Do you have access to a logger? An exhaust leak (upsteam of your O2 sensor) will show lean fuel trims while the car is running very rich. The leak allows air to sneak in to your exhaust, where it "dilutes" your exhaust mixture w/ too much air/oxygen. The O2 sensor "sees" this very lean mixture & reports it to the ECU (closed loop). The ECU then dumps in a bunch of fuel to counter the lean mixture. Over time, the excessively rich air/fuel mixture then carbons up your combustion chambers & causes knocking.

 

[blackmirage]

Ok, I'm still trying to get this taken care of, but I do want to say, as I havent said before. Was that I dont have the exhaust on the car. Its only the Downpipe. I checked for leaks and cracks in the o2 housing and the manifold.. Nothing that I can see. I do have a TB Gasket leak or something leaking by the TB now, It wasnt before when I did a boost leak test, but I tried the sea foam thing and ran it around the block a couple times, didnt help but now this TB leak is popping its head out.. So I'm going to look at that as well as check the timing once I find somone with a timing light or find out if you can rent one from Autozone or something. Appreciate your help King.. I'll look into all this and hit you guys back and let you know.

 

[h3o]

do you have a friend with a 90 ecu? mine had the same problem as your describing and when i looked at the ecu i didnt see anything, but changing it out solved everything. When i did unsolder the caps i saw that it just started leaking out to the point where the only way i could see it, was when i unsoldered the caps. Just throwing that out for ya.

 

[laserwitpsi]

I would get a logger and try that out because that will probably help you solve your problem. My car was running pig rich so I hooked up a logger to it and before the car was even started it showed a bunch of weird curves so I swapped the ecu out with another one and it solved the problem. I thought the ecu was good to because it looked fine, hope it helps.