Hey all,

I need a little help trying to figure out exactly what's going on with my car lately. I've got a 1986 Trans Am with a TPI 305 in it. I can't say when my problems started, because it seems like it's just been going down hill for a while. First off, the car started to idle real rough and the check engine light came on. First I went through the process of replacing dristributor cap, rotor, plug wires and plugs. That didn't really seem to fix anything, because it was still idling real rough and dying while the car was stopped say at a stop sign or stop light. It also smelled like its running really rich.

Finally I got a hint when I checked the error codes... I was getting EGR, MAP sensor, and O2 Sensor. Once I replaced just the EGR, it idles smooth now and no check engine light comes on. When I replaced the EGR valve, I also put in a new fuel filter and I've also got a new O2 sensor if needed, but the old one is in there pretty good, so its not something I wanna try unless I have to Now, after all this, the car still has no power, is running very rich, and is backfiring when idling. When I say no power, I mean I can go around a corner with loose gravel and not even get the car to spin the tires the least bit. This coming from before where I would usually fishtail out of control if I tried that.

Another symptom that just started not long ago is the car is overheating and boiling over, but only when going 60+MPH. If I do 60MPH or slower, the car cools off enough that its not really hot. Driving around town it stays right around 220 on the temperature gauge, which is about normal for that car. I'm missing the front air dam on the car, so I'm not sure if that's the cause or not. Trying to find a replacement one of those if anyone knows of one. I also replaced the thermostat just incase, it seemed to help a little, at least to the point of where it doesn't boil over, just overheats when going 60+MPH.

I'm just looking for any ideas of what I might look at... I haven't made any custom changes anywhere, so I'm at a loss of what to check. I don't know if I got a bad spark plug or not, because I've used a gap checking tool on the plug wires where it had to shoot the spark through the gap to make sure it was getting proper spark through the wire. All the wires gapped it just fine, so that's why I'm thinking it might be a plug or something else.

Any suggestions are greatly appriciated. I'm getting ready to leave for a trip next weekend, so I'm trying to fix as much as I can before then so I'm not dring 55 all the way there. That would make for a long trip, haha. Thanks for any help!!

 

Well first of all, firebirds have to have the Air Dam to cool. If not it will overheat because the radiator isnt getting very much airflow to cool it off. When you say MAP sensor im guessing you mean MAF sensor because only 90-92 cars have MAP sensors. Make sure you MAF is still good and the wire inside of it isnt broken. Also replace all the relays, Check your timing, Take some Carb cleaner and spray inside the IAC valve, Get some Sea foam and put some in the gas tank and let some suck down the power brake booster hose into the engine then let it sit for awhile and start it back up it will smoke like crazy for awhile but that is a good thing it is all the carbon build up in your engine cleaning out.

 

Thanks for the suggestions. I'll give them a try. A new thing that's just developed over the past day or so is a vacuum hose popping off the intake. It happens when I'm starting the car, it tries to start then just dies with somewhat of a pop noise. Its a hose at the back of the intake, on the opposite side of the brake booster hose. The first time it did it, the brake booster hose came off with it, tonight it was just the small hose.

Any ideas what might be causing this?

 

hi i live in the uk and have 1985 t/a with the same problem overheating my air dam was missing i got one in the uk it does it's job antifreeze will help to, there is a shop in the us called thirdgen ranch on line email address dennyb@thirdgenranch.com hope this help's.

 

My 1985 T/A was running rich and burning too much fuel I bought a mass air flow sensor and did not put it in right away because of the price. I replaced several other sensors to no avail. The car started running worse so I decided to put in the MAF and the car ran surprisingly well. The gas mileage returned to normal and the tires burn off like they should when you want them to. It no longer runs rich, and still gets too hot in warm weather at slow speeds. Yes it has an air dam, 180* thermostat, fan always on with a secondary fan, and a 3 core radiator. It runs around 220 in 80* weather if I also have the heat on but that sucks.

 

I would try putting in a new fuel pressure regulator diaphragm. That'll make your car run crazy rich. It'll also blow the vacuum line off the intake.

Take the vacuum line off the regulator off the intake and the regulator. If the regulator is pissing gas, the diaphragm has ruptured and needs to be replaced.