My 94 LT1 was backfiring with a loss of power and i just changed the wires on it and now there is no loss of power but a backfire once in a while. I think its just too much fuel being dumped into the exhaust it was after i let off the gas then i would press the gas again and it would backfire. It went from a loud bang to a quite crackle almost. It sound a lot healthier too when i started it back up. Am i right or is there another problem?

 

If you have misfires due to faulty plug wires, its going to cause the engine to run very rich. The O2 sensors are picking up the air that blows out the exhaust valve when the cylinder misfires, telling the PCM the engine is running lean (when it isn't), and the PCM is pouring in extra fuel.

If changing the wires seems to have fixed the misfire problem, its likely that you have found the problem. It may take a while for the PCM to fully adjust the long term fuel corrections based on no misfires. You could clear the PCM long term fuel corrections by pulling the "PCM BAT" fuse in the panel at the end of the dash. Or just drive it for a while, and let the PCM relearn.

 

intake or exhaust backfire? are you just talking about normal decel popping?

do what injuneer said or just unhook the battery for 20-30min, if your pcm adjusted your a/f and spark while your car was running bad it will try to carry over those parameters

 

I had something similar, and it turned out to be something VERY strange. I had replaced my coil and started getting this problem. At night, I could see the build of of electricity on the coil that it was not discharging and I chalked it up to a bad coil. Changed the coil, same thing. It turned out that my coil wire to the opti was bad. At the coil, the wire inside was dust. How the car ran is beyond me, but it wouldn't hurt to at least look at that possibility, especially if you haven't changed the wires like Injuneer said.

 

I did NOT say to "unhook the battery for 20-30 minutes". I said to pull the "PCM BAT" fuse. 30 seconds is all it takes.

 

congratulations

I said do what injuneer said OR etc, etc

 

i changed the coil wire one of the wires was messed up and i think your right injuneer it sounds as though i just need to drive it for a while but would not having any cats on it be something to do with this?

 

oh and it was exhaust backfire

 

is a intake backfire worse and why?

 

exhaust backfires are usually just unburnt gas detonating

an intake backfire can damage components like IAT, MAF, intake, etc

 

ok so i drove it today and I'm thinking my exhaust is just terrible just straight pipes and its just dumping too much gas into the exhaust. When i accelerate kinda fast it starts backfiring but still with no loss of power. Is it the exhaust or something else?

 

The A/F ratio is controlled by the O2 sensors and the PCM. A faulty exhuast, downstream of the O2 sensors will not affect the A/F ratio, and should not cause it to run rich. A plugged cat will mess things up though - reducing power at higher RPM. The fact you are running no mufflers (and probably no cat) will cause a lot of popping in the exhaust on decel.

If you have no cats, and you have headers with the O2 sensors in the collectors, and you are running open headers, it will run rich due to the backwash of air in the collectors. But you state you have "straight pipes", so that should not be a problem.

Exhaust leaks before the O2 sensors will cause it to run rich. Have you checked the header gaskets?

Just guessing you have headers - you really haven't provided much info at all about your car. Its usually easier to help if you provide basic info - year, model, engine, tranny, and any major mods. That's what the "signature" field is for. First step at this point should be to provide all the required info about your engine. We know the year and engine - tell us about the mods.

Sounds like its still misfiring - that will cause it to run excessively rich.

 

it is a 1994 camaro z28 lt1 6 speed with dual borla exhaust with a y pipe it has headers the guy told me stock aluminum headers has a k&n cold air intake and thats it for any mods. It has no cats or mufflers. Like i said i replaced all wires and it runs 10 times better and now i have no loss of power when it backfires. When i accelerate slow it doesn't backfire otherwise it will backfire.

 

its the t56 tranny as well

 

There are no "stock aluminum headers"..... do you mean stock aluminum heads?

It I understand this correctly, you have Borla (???) headers and a Y-pipe. What's after the Y-pipe? Where are the "straight pipes"?

If its popping in the exhaust on hard acceleration, its misfiring. Could be an exhaust valve hanging open. Misfires usually won't show up when you "accelerate slow", but when you put the engine under heavy load at WOT, that's when it will misfire.