Backfire question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Adam12 · 10-13-2003, 10:58 AM

yesterday I took my truck on the freeway for the first time, I was accelerating to about 70 and then really steped on it, the truck took off of course

but I didnt want to go too fast so I let off the gas at about 85 but it sounded like it was backfiring everytime I let off the gas. It was really loud and sounded like my exaust was going to blow up it happens anytime I accelerate really fast and then let off the gas. Is this normal?

JimKshortstep4x4 · 10-13-2003, 12:01 PM

Backfiring is not normal!

I would check for exhausts leaks first as they can cause a backfire when you let off on the accelerator.

Jim

Adam12 · 10-13-2003, 01:11 PM

Oh so it probally dosent help that I have a exaust leak on my headers and that the collector gaskets have prettymuch completly burned away so there is probally some leakage there too........*kicks self*

lukecp · 10-13-2003, 01:14 PM

Yup....an exhaust leak anywhere in the system will cause that.

Adam12 · 10-13-2003, 01:15 PM

I guess I will spend the money for those copper gaskets mabye they will seal better.

Longhorn Man · 10-13-2003, 11:24 PM

Dead soft alluminum works pretty awsome too. I've had one set on 2 sets of headers and removed and re-installed more times than I can count. Been on since 98 and no leaks.
Your engine is probably a little rich too.
The unburnt fuel in your exhaust hits fresh air sucked in from your lack of collector gaskets and ignites from the temp of the gasses and pipe temp.

dinnut · 10-13-2003, 11:26 PM

i have the same problem except im just revving the engine in my driveawy because my license is non existent

10-13-2003, 10:58 AM	#1
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	Backfire question yesterday I took my truck on the freeway for the first time, I was accelerating to about 70 and then really steped on it, the truck took off of course but I didnt want to go too fast so I let off the gas at about 85 but it sounded like it was backfiring everytime I let off the gas. It was really loud and sounded like my exaust was going to blow up it happens anytime I accelerate really fast and then let off the gas. Is this normal? __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-13-2003, 01:11 PM	#3
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	Oh so it probally dosent help that I have a exaust leak on my headers and that the collector gaskets have prettymuch completly burned away so there is probally some leakage there too........kicks self __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-13-2003, 01:14 PM	#4
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	Yup....an exhaust leak anywhere in the system will cause that. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

10-13-2003, 01:15 PM	#5
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	I guess I will spend the money for those copper gaskets mabye they will seal better. __________________ 70 SWB 481 ci, TH-400, Edlebrok Victor Jr. intake, Holley street avenger 770, Dynomax ceramic coated headers. Dual flowmasters. and only 3516134 more little things to do.

10-13-2003, 11:26 PM	#7
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	i have the same problem except im just revving the engine in my driveawy because my license is non existent __________________ 70 longbed 496/th400/Ford 9"

10-13-2003, 12:01 PM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Backfiring is not normal! I would check for exhausts leaks first as they can cause a backfire when you let off on the accelerator. Jim

10-13-2003, 11:24 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Dead soft alluminum works pretty awsome too. I've had one set on 2 sets of headers and removed and re-installed more times than I can count. Been on since 98 and no leaks. Your engine is probably a little rich too. The unburnt fuel in your exhaust hits fresh air sucked in from your lack of collector gaskets and ignites from the temp of the gasses and pipe temp.



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