Corvette Z06 Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter · #1 ·
I'm not talking about the notorious gurgle that comes from deceleration... I'm talking a good old fashioned backfire that happens both under acceleration and at idle.

It's not one of those happy little small ones either, it's the run for the hills I'm being shot at, kind of backfires.

Could this be caused by a bad O2 sensor? I did some data logging and they appear to be giving off close to normal readings.

What if the spark plugs were gapped too small? They don't fully ignite all the fuel each time, so excess builds up, when it does get a full spark there's too much fuel in one cylinder?

Car's got 231/237 Cam, was tuned just fine prior to this, TPIS headers, Corsa X-pipe with stock cats, and Spec 3 clutch.
 

·
Registered
Joined
·
1,372 Posts
I had similar troubles right after I put in the cam and tuned it. Plug wires were the culprit.
 

·
Registered
Joined
·
722 Posts
This is very unusual- I'd have the tuner look over his retune. It sounds like plug wires are crossed, which can't happen. Let us know, please.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #5 ·
Heh, to the guy that said it does it when cold, that's completely backwards from mine. Mine won't do it until the car reached operating temp. For the most part. Once in a while it'll do it before the oil temp is above 160, but not usually.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #6 ·
ST1100 said:
This is very unusual- I'd have the tuner look over his retune. It sounds like plug wires are crossed, which can't happen. Let us know, please.
We have, but nothing in the tune has changed from before this, and now after this. We are in the process of re-doing the tune completely but this, to me, sounds like a mechanical or electrical problem to me.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #7 ·
Pakisho said:
I had similar troubles right after I put in the cam and tuned it. Plug wires were the culprit.
Smart man you are. (or at least experienced :idea: )

I just checked the plug wires and number 2 and number 7 were both not on all the way, number 7 was barely on at all. I haven't driven to see if this fixed the problem, but will chime in tomorrow and let everyone know.
 

·
Registered
Joined
·
1,372 Posts
I'd say you found the problem. :D
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #9 ·
Pakisho said:
I'd say you found the problem. :D
:bang: Still doing it.

I'm going to check the plugs themselves and see if maybe they aren't tight....

I've also got some other plug wires I'll toss on and see if that doesn't fix the problem too....

.... still diagnosing..... :flaming:
 

·
Registered
Joined
·
1,500 Posts
70boss302 said:
Mine does it only when cold............it doesn't bother me.

I asked a friend of mine about that and he told me that when you first start the car that is running a little rich, and that is what causes it.


Can someone else chime in on this with some more info?
 

·
Registered
Joined
·
654 Posts
Water in the fuel filter from condensation in the tank.
Header gasket leak.
Plug wires/plugs.
Timing is off.
Leak in the intake manifold.

I dunno. Charlie has a new fuel filter of mine if you want to toss it on and see if that cures it. Although it it were water in the line it might stumble also.

I read up on this for about 40 minutes and that's the best I could find.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #12 ·
Lack of tools and hot car foiled my plans. I'm gonna try and tackle it again tonight.
 

·
Registered
Joined
·
2,127 Posts
It is so easy to trouble shoot with a some type of scan tool.
I jhave EFILive,(cost around $400) I hook it up, run the the piss out of the car look at the misfire scans. DONE DEAL
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #14 ·
22655TD said:
It is so easy to trouble shoot with a some type of scan tool.
I jhave EFILive,(cost around $400) I hook it up, run the the piss out of the car look at the misfire scans. DONE DEAL
I've got EFI Live as well as HP Tuners but haven't been able to get a reading consistent enough to determine exactly what the cause is. :mah: I was planning on running EFI Live again tonight and see if I can't find SOMETHING useful. :zboobie:
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #15 ·
Looks like it was a combination of things.

I dug into the car last night and a few of the spark plugs felt a little loose so I snugged them up.

It also felt like some of the wires weren't down all the way.

I guess this is what happens when you rush putting your car back together at 5am to go to work at 6am when you've been working all night. :blush:

Was able to romp on the car a little bit this morning and everything feels like it should.... tires spinning and all. :guiness:

Thanks for everyone's suggestions.... now, back to tuning! :usa:
 
1 - 15 of 15 Posts
Top