Backfiring ... what the devil?

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Aug 24, 2004 | 11:12 PM

jimbomill

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Burning Brakes

Joined: Nov 2001

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From: Cherry Hill NJ

Backfiring ... what the devil?

My '92 Vert has been sparingly used lately, but still has 141K miles on it. I, like several others last fall, put the Corsa exhaust system on it, so I take it out to give it a good "listen". The last couple of days, I notice in the lower gears, if I let it throttle down, it will backfire, which is something it's not done in the 3 years I've had the car. All my manuals got damaged in the flood that hit us on 12 July. What should I check out first?

Aug 25, 2004 | 12:20 AM

bogus

Team Owner

Joined: Aug 2000

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From: San Pedro CA

How old is the optispark? that is a sign it is going south bound...

Aug 25, 2004 | 06:13 AM

kman0066

Burning Brakes

Joined: May 2000

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From: Nashville TN

You could also check if you have an exhuast leak, like a loose clamp or the likes.

Aug 25, 2004 | 07:54 AM

newbecorvetteguy

Melting Slicks

Joined: Jul 2004

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From: OR

If you have the A.I.R. (air injection reaction) system on your car it could be one of the control valves, also known as a diverter valve, or 'gulp' valve. To reduce emissions, air is pumped into the exhaust system. On deceleration, the diverter valves are supposed to close that off. If one of those valves isn't doing it's job you'll get a back fire out the exhaust on deceleration.

Aug 25, 2004 | 08:02 AM

runner140*

Le Mans Master

Joined: Mar 2004

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From: Ft. Lauderdale Fl

Backfire

Take a look at your cat converter and make sure it is clear, also check out your fuel filter. When is the last time you changed it.?

Aug 25, 2004 | 10:13 AM

SilverBeast

Drifting

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From: Mobile AL

St. Jude Donor '05

EGR valve can cause that, too. Sounds like it's definitely in that EGR system somewhere.

Aug 25, 2004 | 12:28 PM

jimbomill

Thread Starter

Burning Brakes

Joined: Nov 2001

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From: Cherry Hill NJ

Opti re-done in the last year.

Aug 25, 2004 | 12:30 PM

jimbomill

Thread Starter

Burning Brakes

Joined: Nov 2001

Posts: 920

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From: Cherry Hill NJ

Last November had the Corsa exhaust system, I did not do it, so paid too much

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Aug 25, 2004 | 12:31 PM

jimbomill

Thread Starter

Burning Brakes

Joined: Nov 2001

Posts: 920

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From: Cherry Hill NJ

Sounds like that is what is happening. Know of a good quick check?

Aug 25, 2004 | 12:32 PM

#10

jimbomill

Thread Starter

Burning Brakes

Joined: Nov 2001

Posts: 920

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From: Cherry Hill NJ

The CAT could have been affected last November when the new Exhaust was put on... do not know about the Fuel Filter, it's got about 10k miles on it, but almost 3 years.

Aug 25, 2004 | 12:33 PM

#11

jimbomill

Thread Starter

Burning Brakes

Joined: Nov 2001

Posts: 920

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From: Cherry Hill NJ

I'm unsure on the maintenence/replacement of the EGR since I had it.

Aug 25, 2004 | 11:32 PM

#12

newbecorvetteguy

Melting Slicks

Joined: Jul 2004

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From: OR

Quote:

Originally Posted by jimbomill

Sounds like that is what is happening. Know of a good quick check?

If you're talking to me about the A.I.R., the way to check is simply disconnect the air hoses going to the exhaust manifolds at the easiest place, start it and give the accelerator a few jabs. If it backfires when hooked up and doesn't when it's not, that's it. Hook up one side, then the other. It should start to backfire when the side with the faulty valve is hooked up.