3.8L Olds backfireing

[Austin8214]

I have a 1989 Olds delta 88 with a 3.8L V6 that seems to be backfireing out the air intake. I have drilled about six holes in the catilatic convertor thinking that was the problem but it wasn't. Help Please.

[danny350]

timing

[Austin8214]

I thought so to but it has good power on top end

[curtis73]

Still something about the timing. Could be not fully advancing or the vacuum compensation could be stuck.

[coop7295]

i would check the intake manifold gasket for staters . spray some 2+2 or any carb cleaner around the intake base and see if you hear a difference in the way it runs if the idle changes pitch you may have a vacuum leak there. also worn cam lobes can cause a backfire at lower rpms. If you have not moved the distributer i would not think the timing would be off unless something else has worn. Does the car have a carb or fuel injection? Has the car been sitting a long time with bad gas? have you done a tune up and crossed some wires???

[Austin8214]

The car is fuel injected. And I have not touch a thing under the hood yet. i also put some good gas in the tank with some dry gas. The only reson i drilled out the converter is i had a similar prolbem with a 3.8L in a beretta and the CAT was the prolbem with that one.

[danny350]

I'd say, there's a good chance the timing chain is worn and retarding the timing badly.

[benchtest]

You haven't mentioned the circumstances in which it backfires. Acceleration / idle / deceleration / heavy accel.? The 3.8L is well known for jumping timing chains (the stock nylon teeth break) and that is a strong possibility if the chain & gears are stock. Did this happen all of sudden, or after some engine work was done? Does it run rough at idle, accelerating, steady state?

[Austin8214]

It idels fine it backfires when you accelerate. but stop when rpm levels out. Also it realy lacks power when going up hills.