Hello Corvette Dudes,

I recently bought a 2003 z06 corvette with only 3500 miles. I drove it home and it drove awesome, about a 4 hour trip. I started it up last night to show my brotherinlaw and when I reved the engine it would backfire when coming down from the rpms. I really didn't give it much time to warm up and it was approx. 40 degrees out. After the car warmed up it didn't backfire anymore. Is this normal for these high strung cars.

Thanks, Ty [&:]

 

Welcome to CF, Ty!
Techincally, "back fire", is firing "back", out through the carb. "Out fire" is firing "out", through the exhaust. Which is it?
I figure that you mean "out fire". It would be the explosive burning of unburned fuel from the engine, taking placein the exhaust system. As far as "normal", I'm not sure on this, concerning your year and modle, of which I'm not very familiar. I believe not though. "Back fire" and "Out fire", are generally the product of improper timing. One or two weak spark plugs could cause "out fire" also. The unburned fuel from one or two cylinders, is ignited in the exhaust system, by the hot gasses from other cylinders. I would think that a good tune up willresove this situation.

 

Welcome to the forum Ty!

I agree C3 - Good call!

[sm=icon_cheers.gif]

 

Hey Ty, congrat's on the Z and welcome to the forum. You're going to love that car.

I believe it is "out-fire" as C3 suggested. The engine is running rich when cold and unburned fuel is entering the exhaust. My 04 Z06 will do the same thing. Just let it warm up. It's probably not that good for the engine to go to high RPMs when cold anyway. Plus, you risk blowing up your cats or mufflers when that happens.

 

Thanks guys for the advice.

I'm taking car to shop this week to get oil changed and ready to put in storage for the winter. I'll have them take a look at it on the computer, I would'nt think it would need a tune up yet with only 3,800 miles.
I'll give it a chance to warm up, would'nt want to damage my new baby.

Ty

 

I was always tought to let them "warm up" before driving and let them "warm down" after. let it run for 1 or 2 minutes before you cut it off

 

I did that there once on a Caprice. I was used to carbuereted cars, and once dropped the hammer there when killing the ignition (as I always did). Unburned gas solves the carbon deposits there in the cylinders. If the pipes are hot there, as they were that morning, the gas can light up. Loudly, too. Opened up the cat like a flower too there.

 

I have excessive out-firing ALL the time...even when slowing down on the freeway...LOUD pops either in quick fast multiples or one REALLY big one...I know the car needs a tune but I'm trying to wait until after I smog it (I live in Cali) so I can put the LT headers on (I have an exhaust leak from a drivers side cracked manifold) before the tune...

 

my 02 zo6 does the same popping sound, I have had the car tuned, I changed the plugs and wires. I have a bbk ssi intake vararam CAI, bassani x pipe, corsa exhaust. Any other Ideas as to what may cause this crappy sound?

 

ok guy's! it is the gasses and unburned fuel inside the header. or manifolds. what happens is when you accelerate the engine requires more fuel. but when you let off not all the fuel is burned, and therefore it will be ignited down threw the pipes. that is where you get the rumble or popping. i have had 3500 dollars of work done to my ls1 and even with the 3 1/2" exhaust it will still rumble as the rpm go down. this is normal and i really do not no of a way to get rid of it other than going with a aftermarket quite muffler.