greasemonkeysoldier

iTrader: (1)

I've been search Tech for about 4 days now trying to find answers. But haven't found what I was looking for. I am having problems with my car backfiring under heavy load....what I mean is whenever i'm "getting on the throttle" my car is backfiring like a fully automatic machine gun. When I'm driving the car like a granny I'm not having this problem. I just recently installed LT headers and a LS6 intake with a P/P TB. I have checked for vaccum leaks, my O2's are working fine, I just replaced the spark plugs.
A buddy of mine hooked my car up to HPTuners and said that I am running lean and so he is going to adjust my VE tables. He said that with all my bolt-ons I'm not getting enough fuel to match the new amount of air the engine is getting.

What I don't get is, people run full bolt-ons without tuning all the time and have no problems. Why is my car running like crap and needing some tuning?

I have also though about cleaning my MAF, but I didn't have this problem before installing my intake and headers so I don't see how that could be a problem.

I am just very frustrated because I have spent all this money to get my car running good and when I took it to the track last night i ran a 14.1@99 mph.
Now mind you this was my first time ever running at a track so my times would have been crappy regardless. But a 14.1? I really need to get my car running right. Any help would be great.

LS6427

iTrader: (2)

First thing...STOP getting on it and having it backfire, that means its missing most likely and that can destroy your engine.

Clean the MAF, sometimes they happen all of a sudden and make the car run shitty. Also, the MAF is not used when doing anything other than WOT or cold start. So the MAF comes into play as soon as you go WOT, then its disabled when you come out of WOT. It could be dirty or it could be failing.

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SpaZMaN

iTrader: (5)

Make sure you don't have a bad plug wire or one is not on all the way. Make sure all the connections for the MAF and IAT are on snugly.

greasemonkeysoldier

iTrader: (1)

Defiantely did that, but i plan on repalcing the plug wires anyways just in case.

yeah i don't plan on it. I just did the one run last night to see if we had fixed the problem. It ran better than it had been running but still wasn't right. i wanted to run again to atleast get a pass that was under 14 sec. but didn't want to risk it. i figured there is plenty of time to get a better run in once my car is fixed so.

I guess I'll clean the MAF just for ***** and giggles and see if that helps any.

SpaZMaN

iTrader: (5)

Another suggestion, if you have the OLD maf, put that on to see if it makes a difference.

greasemonkeysoldier

iTrader: (1)

I'm still using the stock MAF

LS6427

iTrader: (2)

I know this has been said a million times here....but its the #1 cause of missing at WOT and mid-higher rpms.

Any of the plug wires touching or bouncing into the exhaust manifold pipes.

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greasemonkeysoldier

iTrader: (1)

Just cleaned the MAF....and no change....also quadruple checked the spark plug wires and they are fine. I've tried all the obvious things....which is why I'm so frustrated. I'm hoping with some tuning it will be fixed. since I can't think of anything else it could be.

LS6427

iTrader: (2)

Could be a leaky fuel injector. It sucks when no code is thrown for whatever cylinder is missing.

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greasemonkeysoldier

iTrader: (1)

yeah, definately....i guess it could be a fuel injector....maybe one of them didn't seat right? or got clogged when I replaced the intake manifold? I haven't taken them off yet but i have checked them externally and didn't see any leaking. And I have ran a couple of bottles of fuel injector cleaner through the car as well.