Backfire Problem?

[WS600]

Someone please help. I recently changed the heads (stage 2 64cc), cam 222/224, crank pulley, altenator pulley, LT headers, LS6 intake manifold, Screenless MAF, timing chain, oil pump, smooth belows, lid, large diameter y-pipe, loudmouth exhaust, 36lb. injectors, and 3.73 gears, on my 2000 WS6 Trans Am automatic. I paid to have it tuned by LG motorsports and it dosent seem to run right. Recently i started having backfiring problems, bad. It backfires at 60% throttle or more and generrally only at 60+mph. Added to this problem I started hearing pinging to (I do use high octane gas). I purchased EFILive in an attempt to fix the issue. and have made a few adjustments (mostly to transmission settings). Please someone help, I'm not sure what the problem is and how to fix it.::help2:

Also it only backfires when I'm actually in gear, if i run it up to 5000-6000 rpm in neutral it's just fine. (not sure it matters but i thought ,i'd throw it out there)
:help:

If someone can take a look at my tune and log and perhaps give me a little advice on what to do. Yes, I'm a newbie, but i'm dedicated to getting this right.:thankyou2:

[Bruce Melton]

Try the crank sensor relearn.

[WS600]

I'm gonna give it a shot right now. Thanks... Yeah just tried it and didn't change anything. I don't know what to do.

[jfpilla]

Suggest you not go hard on the throttle until you get the tune squared away. It really is bad across the board. I can't believe a pro did it. There are knowledgeable people that can help you on this Forum and can at least point you to some tutorials. You can also get mail order tunes here that would be a good start.

[WS600]

Yeah, your probably right, I don't want to break something. You should have seen where he had the shift points it acted like there was no 3rd gear and stayed in firts intil 32mph no matter what the throttle position. Is the entire tune bad or just air/fuel or any suggestions.

[jfpilla]

It's pretty bad. I'm on ther way out right now. Hope someone can get you started, but it is saturday night.

[WS600]

I hear ya, think i'm calling it quits tonight. It's beer time, take it easy.

[WS600]

I read that someone else had the same problem and he fixed it by just changing the plugs and wires. Mine plugs/wires only have about 1000 miles on them. Could they have gone bad?

[jfpilla]

I read that someone else had the same problem and he fixed it by just changing the plugs and wires. Mine plugs/wires only have about 1000 miles on them. Could they have gone bad?

You can't rule out mechanical issues, but the tune is :bash: .

[Bruce Melton]

Are you saying that the tune as posted above is what was derived by LG for your current configuration?
If so, they owe you a redo or is there is something you are not telling us?

[WS600]

No, the tune by LG was so bad the car didn't even know what gear to be in and it barely ran. I think this was caused mainly from the transmission settings but It seemed to be to lean after I hooked it up to a wideband O2. Attached is the exact tune I received from LG (minus very few shift point changes, I kept the original on another computer for backup). After comparing some things are the same and others aren't too different. The tune listed previously was paid for from an on-line store. I seem to be having bad luck.

[WS600]

:beer: Any words of advice? Was their tune just fine and I had a mechanical problem? The car's not backfiring anymore but I don't know if it's becasue I changed the plugs and wires or because of a recomendation to change the tune. Reguardless, much thanks to any and everyone's advice and help. I've learned alot about EFIlive in the past week that I probably would not have if not for everyone's help. I still got alot of learning but thanks. :beer:

Thanks, I'm gettin there with everyones help....:rockon:

Jake

[Biggsy]

Still have your old plug wires?
Measure the resistance of each one, maybe a dud one.
Easiest way to tell if the wires were the problem is to put the old ones back on and see if the problem comes back.

What about the condition of the plugs when you pulled them out?
Were any of them a different colour on their ends?
What were their gaps like?

[joecar]

If plugs don't look "normal", post pics.

[jfpilla]

No, the tune by LG was so bad the car didn't even know what gear to be in and it barely ran. I think this was caused mainly from the transmission settings but It seemed to be to lean after I hooked it up to a wideband O2. Attached is the exact tune I received from LG (minus very few shift point changes, I kept the original on another computer for backup). After comparing some things are the same and others aren't too different. The tune listed previously was paid for from an on-line store. I seem to be having bad luck.

The LG tune is not awful. It's different than what I would do, though. Particularly, unless you didn't have 36lb injectors at that time.
It has the TC locking at upshifts. Not good and may be part of what you sensed as shift problems.

[WS600]

According to the Haynes book my ohm load on the wires was in the correct range.6 but I only kept 4 of the 8 so it could have be one that I threw away. Also the plugs look okay but I'll attach a few pictures to see what anyone else thinks. And the gaps on all but one were .053 and the one was .060.

[WS600]

It's been taken care of, thanks for everyones help

[Biggsy]

It's been taken care of, thanks for everyones help

What was it?

[WS600]

Combination of both, bad plugs and bad tune. The plugs got rid of the backfiring problem and a new tune got rid of the smoke.I believe the cause of the plugs going out so quickly was the tune but hard to prove unless I install the old tune and run it for about 1000 miles (thats how long it took the last set to go bad). The transmission problems were all from LG's tune.

[Biggsy]

Good to hear you are all up and running :cheers: