1991 running bad
Thread Starter
Cruising
Joined: Oct 2003
Posts: 12
Likes: 0
From: Chandler AZ
1991 running bad
I bought a 1991 C4 with 19K. It is a 6 speed, with Trick Flow heads, aftermarket chip, BBK throttle Body. The car ran fine for the first 6 mos. Now, when I first start the car it runs fine. After the engine warms up, it won't idle and it surges. I also get no codes. The weird part is, none of this happened until a real hot day (~117 degrees). It was almost like something got damaged in the heat. I've replaced the plugs, wires, cap, rotor, and even cleaned the injectors. I'm at a loss, any help would be appreciated.
Thanks
Thanks
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Re: 1991 running bad (sdaztecs)
Does the exhaust smell funny, like a blown head gasket?? Lot of white smoke coming out (steam). Can you get readings from the car with scanning software. Let some other folks on here know what's up.
Thread Starter
Cruising
Joined: Oct 2003
Posts: 12
Likes: 0
From: Chandler AZ
Re: 1991 running bad (Goody)
I cleaned the throttle body, twice and it has a brand new IAC that was professionally installed. There is no white smoke or funny exhaust smell. I've blown a head gasket before and it's definetly not that. The car runs perfect until it gets hot. Does it sound like a certain censor, or a bad injector?Any ideas would help, thanks again.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Re: 1991 running bad (sdaztecs)
Verify code 12 and that it can set a code by disconnecting the TPS. Aim a hair dryer at the PCM (not too close) with the engine cold. If stall is duplicated prior to warmup, it may have a bad solder joint. Check resistance at the coolant temp sensor or with a scanner. At 212 degrees, resistance should be low or about 160 to 170 ohms. You should also verify the air temp sensor, but because it's under the plenum, the only way to check it hot is with a scanner. You can also check injector resistance cold & hot. Hot is usually higher, important that they all be the same. Usually though, the IAC can compensate for a dead injector so suspect more than one if you find a bad one. Otherwise, start checking connectors or if you've spliced or repaired a wire, look there first. Hope this helps.
