(1992) Backfire when shifting first to second, auto.
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From: Rutland Ma
(1992) Backfire when shifting first to second, auto.
When i floor the gas the car backfires when it shifts from first to second. I'm not sure about second to third but i could find out real quick if needed :D . A couple more details the shift is starting to feel a little sloppy. The car has SLP 3inch exhaust which has pretty much fallen apart. The baffles or something has come apart in the resonator and vibrates like crazy. So i got mad the other day and tooke everythng from the cats back off. It still backfire on the gear change, any ideas?
Burning Brakes
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Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
Nobody has ever had a problem with backfiring before? It only backfires when it upshifts.
Shure mine does it all the time.... dunno what is causing it ... yet
edit: and only on WOT at 5800 rpm
:cheers:
Daniel
[Modified by Daniel DK, 9:20 PM 7/7/2003]
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From: Rutland Ma
Re: (1992) Backfire when shifting first to second, auto. (Goody)
Replace your Optispark unit and the issue will be solved.
Safety Car
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From: Houston Texas
Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
Any chance of a lean condition. I only say this because my blower installation manual says if this occurs that you are having a lean condition. Just guessing. Put it on a diacom or have dealer analyize it on dyno hooked up to computer. If this is true then you need o2 sensor.
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From: Rutland Ma
Re: (1992) Backfire when shifting first to second, auto. (BAM92)
I dunno know if its running lean but i always suspected it was running rich. The insides of the pipes are pretty filthy (black sooty).
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From: Mexico Beach FL
Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
I seem to remember that, some time ago, I read an article that this was a known problem with the stock ECM programming.
My memory on this is kind of vague, but I believe it was a Formato article stating he was the only one that corrected this problem in his programming of the chip.
Tom Piper
My memory on this is kind of vague, but I believe it was a Formato article stating he was the only one that corrected this problem in his programming of the chip.
Tom Piper
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From: San Pedro CA
Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
1992's are more prone to popping and such than the later editions.
My 92 has popped like a big block with sidepipes since the day I bought it... and I have replaced the opti (it is due again, tho...).
My 92 has popped like a big block with sidepipes since the day I bought it... and I have replaced the opti (it is due again, tho...).
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From: Rutland Ma
Re: (1992) Backfire when shifting first to second, auto. (ld85)
Backfire from the intake or exhaust?
Burning Brakes
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Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
It may be your opti. It wasn't for me. My 92 still backfires through the exhaust when it shifts from 1 to 2 at full throttle. I think the problem is it's overrunning the rev limiter.
Instructor
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From: Mobile al
Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
There was a updated chip that was supposed to fix or at least help with this on the 92 vettes.
If you have access to a shop that can read the ecm they can tell you if you have the most current software or not.
If you don't I'm not sure where you can go and get it, most likley the dealer.
Mine has the latest but will still back fire once in a while on the 1st to 2nd WOT shift, I also see spark retard in the same area with a scanner.
I'm guessing they set the spark advance a little aggresive at that point hence the backfire and spark retard (knock).
If you have access to a shop that can read the ecm they can tell you if you have the most current software or not.
If you don't I'm not sure where you can go and get it, most likley the dealer.
Mine has the latest but will still back fire once in a while on the 1st to 2nd WOT shift, I also see spark retard in the same area with a scanner.
I'm guessing they set the spark advance a little aggresive at that point hence the backfire and spark retard (knock).
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From: Rutland Ma
Re: (1992) Backfire when shifting first to second, auto. (kbklt1)
There was a updated chip that was supposed to fix or at least help with this on the 92 vettes.
If you have access to a shop that can read the ecm they can tell you if you have the most current software or not.
If you don't I'm not sure where you can go and get it, most likley the dealer.
Mine has the latest but will still back fire once in a while on the 1st to 2nd WOT shift, I also see spark retard in the same area with a scanner.
I'm guessing they set the spark advance a little aggresive at that point hence the backfire and spark retard (knock).
If you have access to a shop that can read the ecm they can tell you if you have the most current software or not.
If you don't I'm not sure where you can go and get it, most likley the dealer.
Mine has the latest but will still back fire once in a while on the 1st to 2nd WOT shift, I also see spark retard in the same area with a scanner.
I'm guessing they set the spark advance a little aggresive at that point hence the backfire and spark retard (knock).
Safety Car
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From: Mexico Beach FL
Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
Like I said in a previous post above, this is a known problem.
See this site and search on "backfire." http://www.c4vettes.com/92sb.htm
Here is the text:
Service Bulletin Number: 92-336-6E
Bulletin Sequence Number: 186
Date of Bulletin: 9212
NHTSA Item Number: SB032290
Make: CHEVROLET
Model: CORVETTE
Year: 1992
Component: ELECTRICAL SYSTEM:IGNITION:ELECTRONIC CONTROL UNIT
Summary: ENGINE BACKFIRE DURING WIDE OPEN THROTTLE 1-2 UPSHIFT DG
Tom Piper
See this site and search on "backfire." http://www.c4vettes.com/92sb.htm
Here is the text:
Service Bulletin Number: 92-336-6E
Bulletin Sequence Number: 186
Date of Bulletin: 9212
NHTSA Item Number: SB032290
Make: CHEVROLET
Model: CORVETTE
Year: 1992
Component: ELECTRICAL SYSTEM:IGNITION:ELECTRONIC CONTROL UNIT
Summary: ENGINE BACKFIRE DURING WIDE OPEN THROTTLE 1-2 UPSHIFT DG
Tom Piper
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From: Rutland Ma
Re: (1992) Backfire when shifting first to second, auto. (Tom Piper)
Tom Piper,
Thank You, that site is very informative. Just a stupid question for those that know, This is different from a recall? Does the dealer have to replace it for free?
Thank You, that site is very informative. Just a stupid question for those that know, This is different from a recall? Does the dealer have to replace it for free?
Safety Car
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From: Mexico Beach FL
Re: (1992) Backfire when shifting first to second, auto. (Chefskeez6)
This is different from a recall? Does the dealer have to replace it for free?
But, a Technical Service Bulletin (TSB) doesn't have to be done at all -- however, if the vehiclel is in warranty and you complain, they will usually do it for free.
I have found it is a good idea to search the TSBs just before your vehicle goes out of warranty and bitch to have them done.
Tom Piper
[Modified by Tom Piper, 2:59 PM 7/9/2003]
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From: Rutland Ma
Re: (1992) Backfire when shifting first to second, auto. (Tom Piper)
My vehicle is 11 years old and on its third owner so no warranty. Is this an expensive thing to have done. Anybody with a 92 have to pay for this before?
