Hello Everyone. Several months ago, I attempted to get a 1987 trans am GTA with the 350 TPI running.
(Original post: https://www.thirdgen.org/forums/tech...runs-like.html)
The car ran terribly, and extremely rich. Now It wont run at all.
I turn the key, and the engine turns over. It will attempt to fire a couple times, sputter a little bit, but if you keep trying it will just spin the engine with no fire. back before this happened, when the car still ran. I drove it to an exhaust shop to see about having some new pipes put in. (Everything behind the cat was junk) when the car was running on the lift, I saw the cat was glowing red hot. I also saw that the Y-pipe had ruptured along the back of the engine. So I took the car to a local auto shop here in STL they said I had a clogged cat, but that wasn't the only problem (they didn't tell me anything else). Oh boy. I have a lot to say about that shop, but not in this post. I didn't end up paying them to do any work after they refused to remove the cat without buying a new one. (not their fault, ik but still annoying.) I limped the car home, barely running at this point and it would not idle. the car stalled at the entrance to my neighborhood, and would not start again. I cut the cat off, later, but that didn't fix my problem. The car was also on it's 3rd ignition module. (replaced it again, but that didn't help.) I looked at the plug wiring diagram and discovered that plugs 1 and 7 were switched. plug one wasn't actually plugged in either. I replaced the ignition coil, cap and rotor. I tested the pickup coil too. service manual said its supposed to read OL, but I got some crazy resistance like 4Mohms which then climbed to infinite. my buddy said it was probably fine, and I didn't want to remove the dist. assembly. (I don't have a timing light) but the dist. does look like its rotated a little too far from what i've seen in pictures. One of the screws holding it down is actually rotated under the cowl, and cannot be removed with a normal screwdriver.
One of the key things I realized before, was that even when jumping pin A and B on the ALDL connector, the CE light does not flash even the standard code 12. It just stays on solid like it normally would if you turned the key to on with engine off. Sometimes If I re-seat the jumper, the light will go out for a fraction of a second after it first lights up with the key on, but then stays solid. Everywhere I looked online indicated that when this happens with any car, 90% of the time its a dead ECM. Last week, I got a data cable from red devil river, and tried to plug it into the car. I could not get it to do anything however. Yesterday I took the ECM out from under the dashboard and discovered that the ECM i had was a reman from back in the day. someone also stuck a superchip in the car, so I don't have the factory PROM. took the thing apart, visually everything looked ok. As of right now I have not reinstalled it into the car.
My theory on what went wrong is after the Y pipe ruptured, It started blasting hot exhaust gas all over the back of the engine (and distributor), and the firewall. under the dashboard, I found what I thought to be a mouse nest and a chewed wire, but couldn't find any mouse leavings. The wire turned out to be a melted vacuum line, and the ball of fluff seemed to be the sound deadening that had degraded in the heat. a couple of the wires that were real close to the firewall had a small amount of copper exposed through melted insulation, but I couldn't find any shorts.anyways between the repeated bad ignition modules (apparently they are very sensitive to heat) and the melted stuff under the dash, I think the ECM may be cooked. What do you guys think. I have very little money to spend on this car, and would like a second opinion before I throw a new ECM at it.

 

Being succinct is a virtue.

Regardless of what caused the issue, yeah it could be a dead ecm, dead aftermarket chip, or both. If you're too cheap to spend $100 in three months to find out, reviving junk cars might not be the hobby for you. Also have a look at the backside of your fusebox and make sure it's not packed full of junk that could be shorting everything out. Sounds weird, but that was a problem I had.

 

Whats your fuel pressure like?


might be a bad fuel [ump

 

Air, Fuel, and Spark. Find out which one your not getting and you will know which direction to go forward in. Also, you are going to have to replace the known problems first. Only then, can someone give you more than a guess or an opinion.

 

Hello, turns out the ECM was dead, the pickup coil was on its way out (and was shorting the ingredients modules) and in the middle of all this the solder on the brass heater core had also melted. Didn't find out about that until flushing the coolant system a few times trying to get all the sludge out. I managed to find the V2.0 part number computer (it had a 636 in it I think) out of a fire c4 in a Florida junkyard (they had the audacity to charge a core charge for a part they didn't rebuild, but whatever, it was still cheap, just hard to find. I have since also resoldered several bad joints on the original ECM and was able to make it function again. I took it back out because it still has spotty trouble communicating over my ALDL diagnostic serial cable, but I'll keep it as a spare anyway. The car runs great and has given me very few if any problems that were not there already when the car came into my possession. This car has a new cat and a rebuilt stock style exhaust system and is now my daily.