OK, about a month ago installed a new opti and waterpump because my car was lagging bad. My WP was leaking on my opti so I thought it was the opti. During the install I noticed that one of my spark plug wires got burned on my headers. SO... I ordered a Taylor OVC kit with wires and all.

After the install it ran beautifully! All my power was back! About a week later I heard a scratchy noise. One of my wires was rubbing against the serpentine belt. It has minor scratch in it. You can see the insolation but the wire is not exposed. Could this still be my problem? I noticed a couple of the boots i installed on the wires was not flush with the little metal crimp thing. So I fixed that and still the same proble.

It ONLY backfires when in gear! If it's in neutral I can rev it all the way and quickly release the gas and it sounds fine but when I throw it in gear forget it! Any suggestions?

 

do you still have the stock cat? If no, then thats the problem. mine back fires also when I let off after getting on it. The car knows its in gear so it sends more gas in. When in neutral it doesnt richen it up

 

It's definately an aftermarket. I thought of that earlier but I thought it was odd that it would go bad right when I start having problems with my wires and opti... I can't rule it out though.

 

Actually I replaced my MSD coil with a brand new Crane Cams coil. I can try putting in my old one for **** and grins...

 

Im sorry , I should have said " do you have a cat?" thats when you run into some backfires. I do

 

Crank it up after dark with the hood up and see if you can see any arcing around the opti, wires and spark plug boots. That'll tell you if the nicked wire is bad or any other spots are leaking voltage. If thats OK, try a different coil to see if that makes a difference.

 

I checked for arching earlier. Didn't see anything wrong. I hate to give up but if the coil doesn't work I'm probably gonna have to take it in.

 

Oh... How long does it take for the computer to reset after you unplug the battery? Do you think resetting the computer might help at al?

 

Is it backfiring out the exhaust when deccelerating or under load? Or is it backfiring out the intake?

 

It backfires out of the exhaust under load. I don't remember if it does the same thing during decceleration. But when it's in neutral the RPM's drop from 5K to idle with no backfire.

 

My Z backfires out the exhaust when deccelerating and I consider this normal as many of the cars I've owned did that. Hell, I downshift my auto sometimes just to hear it pop out the flowmaster. Backfiring under load, however, is not so cool. Are the plug wires adequately sepparated so they aren't crossfiring to another cylinder?

 

Seperated??? I'm not exactly sure what you mean.

I know what you're talking about with the deccelerating. Both the Z28's I've own do that. But this one is NOT normal. It backfires in spurts, not just a single boom. That's what leads me to beleive it may still be the wires OR the plugs which are NGK TR55's installed about 4K miles ago with my other set of wires.

 

If the wires are touching or crossing each other the spark energy can sometimes jump from one wire to the other causing the wrong spark plug to fire. That usually pop out the intake cause if it fire a plug while the exhaust vale was open, the cylinder has already burned up the air/fuel and is getting rid of it. If an intake valve is open and it crossfires the plug, it will ignite any air/fuel in the intake and backfire out of the intake.

It wouldn't hurt to pull the plugs and see if any of the cylinders are misfiring.