Engine Assistance

[J. Halm]

'88 Grand Am 4 Cyl
Very suddenly started missing, cuts-out, runs rough, dies & lost power. Especially at low RPM's. Once to a constant RPM it is driveable (barely)
ECM Codes:
13 - O2 Sensor Ckt Open
25 - MAT High Temp
35 - Idle Speed Error

O2 and MAT Sensors both Check OK.
Suddenly started on a cold start in the morning. Thereflre, I doubt if it is wiring problem.

Can any engine experts offer assistance?

[4kQuad]

Idle speed sensor could cause the problem. It tells the computer how much gas and air to mix to make the car run. If the computer is getting the wrong info, things won't run right.

[p8ntman442]

sound like your getting way too much fuel, I would look at the iac and make sure it is functioning properly. unscrew it and clean it out, they get carboned up and stop working properly.

[ironray75]

Where is the IAC sensor on a 2.5?

[p8ntman442]

on the back of the tbi there is a cylinder that has a rectangular plug, it is held in by two hex screws. It comes off and you will see a pintle and a spring, they stay connected, just clean it up, my car was running rough one time and I cleaned it up and it ran better. Then you will have to reconnect it and disconect the battery for 30 seconds and then reconnect it to reset the computer and get rid of the codes.

[ironray75]

Thanks. I will have to check it out. My 85 is sure to need that cleaned.

[p8ntman442]

iron ray while your out there wrenching and degunking, make sure to take off your egr and clean that shizzy cause when that sticks, all hell breaks loose and the next thing to go is an o2 sensor. Our cars have enough trouble with burning up the o2 sensors without all that exhaust gas recirculating when its not supposed to. Just get a vaccume tester and hook the hose to the niple on the disconnected egr (UFO looking thingy in front of the tbi) then make sure that it can hold a vaccume, if it cant, get a new one, cause your car will run like shit without a good egr. If it does hold a vaccume, make sure you can get the pin to slide in and out easily, i Used a spray to get in there and clean the carbon. A lil wd40 after and it works like a charm after 150k miles.

[ironray75]

Thanks for all of that good info. I just have to figure out what an ERG looks like. I am still learning about all of this mechanic stuff..lol. Thanks again.

[p8ntman442]

like i said the egr is the (UFO looking thingy in front of the tbi) the only thing sittin there in between the tbi and the valve cover. ohh and while you have it off do the valve cover gasket, cuase it is leaking (im telpathic, not really they just all leak) use a good steel core rubber gasket. you have to remove the egr to do it anyways. Make sure to follow the correct torque requirements and sequence. The oil leaks all over the engine from this making it messy and it messes up the coils too.

[ironray75]

Now that is what I am talking about. Thanks for that pic and the info. I will check it out when I get home from work. Thanks.

[newfie_ga]

can't believe I've never thought to do any of that stuff in the year I've had my car. Thanx bye's.....oh, and p8ntman...what's wrong with our beer up here, huh?

[ironray75]

Originally posted by p8ntman442
like i said the egr is the (UFO looking thingy in front of the tbi) the only thing sittin there in between the tbi and the valve cover. ohh and while you have it off do the valve cover gasket, cuase it is leaking (im telpathic, not really they just all leak) use a good steel core rubber gasket. you have to remove the egr to do it anyways. Make sure to follow the correct torque requirements and sequence. The oil leaks all over the engine from this making it messy and it messes up the coils too.
Finally found the Erg. Had to take the entire air cleaner housing off of the TB to get to it. Looked at it, and it was cleaner than I was..lol.. Thanks for the pic again. Really helped..lol