BACKFIRE ! >: [
Thread Starter
Running Guns & Moonshine
Joined: Aug 2001
Posts: 12,498
Likes: 7,182
From: CT
BACKFIRE ! >: [
Ok, there are a lot of little things that **** me off about my car right now. Leaky rear, new weatherstripping installed incorrectly and is torn straight through, tranny that pops out of 1st and Reverse despite my leaning on the shifter, busted (and irreplacable apparently) top mounts for roof in trunk, etc.....
But most angering of ALL...... even after two new MAFs, one new IAT, resodlered IAT wiring and complete replacement of IAT wiring to PCM..... the damned car still backfires! Not just when its cold either, if anything it does it more when its warmed up. Late-model, state of the art, performance-oriented sequential fuel injection on one of the world's best sports cars......... and it BACKFIRES.
Understand: the car has stock everything, mufflers are the ONLY mod.
The car has had problems with engine management since..... LAST summer of '01. It took them several attempts and visits before they found the faulty MAF. More to realize it wasn't the MAF, but the IAT. And since then they have been unable to resolve these issues despite reprogramming the PCM with updates, etc.
Car just backfires. In driving it for an hour, it'll backfire 6 times. So once every 10 minutes or so. That's not "tragic" yet, but that's pretty damned BAD.
Anyone else have a C5 doing this? What else might I have the shop look at as far as problems with engine management? I mean, I'm intimately familiar with the systems.... not much different from my LT1. But maybe there's something I don't know. In any case, I've never touched the car while its been under warranty and I'm not going to until next week once it goes beyond. So I might as well have the dealership take one last stab at this.
But most angering of ALL...... even after two new MAFs, one new IAT, resodlered IAT wiring and complete replacement of IAT wiring to PCM..... the damned car still backfires! Not just when its cold either, if anything it does it more when its warmed up. Late-model, state of the art, performance-oriented sequential fuel injection on one of the world's best sports cars......... and it BACKFIRES.
Understand: the car has stock everything, mufflers are the ONLY mod.
The car has had problems with engine management since..... LAST summer of '01. It took them several attempts and visits before they found the faulty MAF. More to realize it wasn't the MAF, but the IAT. And since then they have been unable to resolve these issues despite reprogramming the PCM with updates, etc.
Car just backfires. In driving it for an hour, it'll backfire 6 times. So once every 10 minutes or so. That's not "tragic" yet, but that's pretty damned BAD.
Anyone else have a C5 doing this? What else might I have the shop look at as far as problems with engine management? I mean, I'm intimately familiar with the systems.... not much different from my LT1. But maybe there's something I don't know. In any case, I've never touched the car while its been under warranty and I'm not going to until next week once it goes beyond. So I might as well have the dealership take one last stab at this.
Thread Starter
Running Guns & Moonshine
Joined: Aug 2001
Posts: 12,498
Likes: 7,182
From: CT
Re: BACKFIRE ! >: [ (jfpilla)
True, any problem not solved must be fixed.
Backfiring occurs both while driving and decelerating. It isn't biased. If it were just under deceleration I wouldn't have such a bug up my backside.
Backfiring occurs both while driving and decelerating. It isn't biased. If it were just under deceleration I wouldn't have such a bug up my backside.
Drifting
Joined: Aug 2002
Posts: 1,317
Likes: 0
From: Lancaster CA
Re: BACKFIRE ! >: [ (Brett C5 SCCA)
Wow, popping during deceleration is kind of normal with a stock exhaust. Your's is the first I've heard of with backfires during normal driving. Sorry, I don't have anything to offer. :( :lol:
Race Director
Joined: Mar 2000
Posts: 17,602
Likes: 20
From: Palm City Florida
Re: BACKFIRE ! >: [ (Brett C5 SCCA)
I know a lot of people are going to tell me I am full of crap.. But try this...
I have Corsa Indys, TPIS headers and X-pipe and I know what "normal" popping and gurgling on deceleration is.
But, for months my car was backfiring like gun shots! Not all the time but just enough to be embarrasing.
Well I got my LS1-Edit 2 weeks ago and decided to do a pcm read to a file. It turns out that ANY time the PCM is read or written to it resets completely. I did a full five minute Idle relearn also.
When I got in the car to drive it I almost died...IT was a different car! All that embarassing noise was gone. All that was left was that nice deceleration gurgle.... :D
My advice to you is do a PCM reset and then a full Idle relearn...IT's worth a shot...Can't take more than 10-15 minutes to do it..
I have Corsa Indys, TPIS headers and X-pipe and I know what "normal" popping and gurgling on deceleration is.
But, for months my car was backfiring like gun shots! Not all the time but just enough to be embarrasing.
Well I got my LS1-Edit 2 weeks ago and decided to do a pcm read to a file. It turns out that ANY time the PCM is read or written to it resets completely. I did a full five minute Idle relearn also.
When I got in the car to drive it I almost died...IT was a different car! All that embarassing noise was gone. All that was left was that nice deceleration gurgle.... :D
My advice to you is do a PCM reset and then a full Idle relearn...IT's worth a shot...Can't take more than 10-15 minutes to do it..
