I advanced my timing to 16° and it made my backfiring problem better; it didn't cure it, but it happens less often and is less violent (it only happens when I shift). I know I've had this conversation before, but do you think it confirms that the timing chain is toast or that the balancer has rotated?

It doesn't seem to knock at 16° (the 2.8 doesn't have a knock sensor does it?). It does perform slightly better now.

 

what was ur backfiring problem because when i let off on the gas with it in gear and it is coasting down it will backfire then sometimes. is that the same thing you are doing or is it different?

 

No, that's not what I'm referring to. Mine does have a soft backfiring sound when the car is driving the engine, but I have this loud pop when the throttle goes from open to fully closed. It gets worse under high load and/or rpm and I believe it happens when hot and cold. But the timing advance to 16° does seem to have helped. I am leaving it there for now unless I have problems.

 

That sounds to me more like an ignition module problem. Your timing is going haywire from computer havoc. Have you replaced this recently at all in the past?

 

Brand spankin' new distributor (Cardone) including module/pickup/cap/rotor last summer with probably less than 1000 miles since then. I had this problem before I replaced the distributor too, the new one changed nothing.

 

O.K. then that rules out the ignition. Next you'll have to check for a vacuum leak somewhere. If you are sucking air somewhere after the TB the car can backfire.

 

There also could be a possibility of a leaking intake valve. You may want to do a compression test.

 

Ya, I do need to check for vacuum leaks, it's so tedious though. Strange how it happens only when shifting.

As for compression, I did a test last summer and got 145 all around.

 

Are you remembering to disconnect the EST when you are checking your timing?


I think it may be possible you jumped time a lil bit.

 

Alright, give me a little credit here. Of course I disconnected the EST. I've set the timing a hundred times.

What exactly does jumped time refer to?

 

It means that on one of the gears, the chain slipped over one notch. So basically instead of both gears spinning and lining up every time, one is always a notch back (or 2 or 3, however much it jumped). Since yours is running, I'd say that it didn't jump much if it did jump.

I would say maybe you were a tooth off on the distributor, but if it was doing this before the distributor install, then most likely not. However, to be sure, you can get the (someone else will have to doublecheck me on this, it's been a while since I worked on a 2.8/3.1) #1 cylinder to TDC (Top Dead Center), and isee if the rotor is pointing towards #1. If not, unstab and restab the distributor until it is.

 

Well, I'll take care of everything that needs to be lined up when I do the timing chain this summer.

Thanks.