Mechanics

ENGINE BACKFIRES WHEN STARTING

1988 Buick Electra

Engine Performance problem
1988 Buick Electra 6 cyl Front Wheel Drive Automatic 147000 miles

I have an 88 buick park ave electra that is backfiring when I start it.

Some history of what I have replaced.

I was having problems with the car dying after it had been driven for awhile, and not wanting to restart. It would restart if it had sat for awhile. Well I replaced the fuel filter, the injector o-rings and the IAC motor, the spark plugs and wires, fuel pressure regulator, all to no avail. I then replaced the ignition coil, and wa-la, the car would start, somewhat hard, and backfired once or twice when starting.

I tried to start the car the next day and the car was suddenly backfiring a LOT and would only start with starter fluid. It would run with high rpms, then as it dipped back to 600-800 rpms, it would die. If I kept feathering the accel it would stay running, and eventually after prob 2 mins of this it would run without having to feather the accel. Couple days later I tried to start it again and it would not start at all, starter fluid or no. I get constant manifold backfiring when trying to start, and it will run very rarely.

I am running out of ideas of what to check.I had a thought that maybe IAC went bad, which caused the backfire, which then blew the gaskets, so even when we replace IAC, I still get the backfire, but I'm not sure. This last part has all been conjecture, but if I remember correctly, the backfire when starting happened about the time when I checked IAC for problems.
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Detra319
February 5, 2010.



From what you describe it sounds as if when the car gets to 100 degrees or closed loop the car runs fine. That would tend me to beleive that it is a basic ignition problem or a vacuum leak. But the vacuum leak may not be large as the computercan take over by richening the fuel mixture. If yor problem seems to start with changing the IAC then first thing to do is see if there are any codes store and what they are. Next thing would be to check the distributor cap for cracks as it may be firing on 2 cylinders. It would look like a pencil streak between 2 cylinders or one cylinder and the coil tower. Also clean the throttle plate with choke cleaner make sure to check all vacuum hoses for softness or kinking. The plug/coil wire may be shorting out someplace n te engine as well. Other than that a pro should look at it if you can't fix it so he may be able to see something you aren't.

Hmac300
Feb 9, 2010.
Service engine soon light is on, so that would prob lead me to agree with vacuum leak. I just found the procedure to pull codes on it online last night, so I will pull the codes and see where that gets me. I will trace out the vacuum hoses and see where I get. Will check back in a day or so, thanks!

Tiny
Detra319
Feb 9, 2010.