backfire from passenger side - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1974blazer · 01-30-2009, 12:28 AM

i have a 1974 blazer, for some reason my passenger side pops, i have replaced spark plugs and cables, changed fuel filter, i cleaned out the carb, and it still does the same thing, could it be timing? it never did this before, i upped the timing from 8tdc to 11tdc, i have an edelbrock 650cfm performer, performer intake, umm any other questions you can ask to try to help me out

thanks
Robert

James McClure · 01-30-2009, 01:24 AM

Robert. Put the truck in gear, hold the brake firmly. Accelerate rather hard but not WOT. Does it pop rapidly and steadily? If it does, chances are real good you have a cam lobe that has worn flat. Do a compression test. If a cylinders reading is real low thats the one. To verify your findings, remove the valve cover and start the engine and look for a rocker that isn't moving much. If you find one isn't moving you have a cam & lifter job to do sorry to say. jim

James McClure · 01-30-2009, 01:32 AM

Bob, welcome to the board. I just saw your new here. If you wish you can call me and I'll walk you thru this and answer your questions as best as I can. If I know the answer I'll tell ya. If I don't I'll tell you that too. 518 581 1622. jim

1974blazer · 01-30-2009, 04:51 PM

Thanks mr james, well i tried what you have said and it just makes the tires burn out no popping at all, its just a normal pop from flowmasters, someone told me it might be the timing, or running rich, i have no cats., i have a point distributor, when i punch the gas it hesitates but when i lay off and just cruze it rides cool!

1974blazer · 01-31-2009, 04:21 PM

i was in my blazer right now, when the car is cold it runs great and once it got hot it lags, i was talking to my friend and he said all this started because my carb was dirty, anytime i clean the carb out it runs good, i have a see through fuel filter and i see rust, could that be the cause of it? on monday in my day off ima check the lifters, im guessing its my carb, all this started happening once my carb was getting filled with rust, ima try using my friends carb and if it runs great, than i know what the cause is and im putting mine up for sale, what sux is that the carb is a tear old...

1974blazer · 01-31-2009, 04:31 PM

i have a edelbrock 650 cfm performer, can you tell which knob is the air and which is the fuel? i think its running rich

01-30-2009, 12:28 AM	#1
1974blazer Registered User Join Date: Jan 2009 Location: Tucson, Az Posts: 15	backfire from passenger side i have a 1974 blazer, for some reason my passenger side pops, i have replaced spark plugs and cables, changed fuel filter, i cleaned out the carb, and it still does the same thing, could it be timing? it never did this before, i upped the timing from 8tdc to 11tdc, i have an edelbrock 650cfm performer, performer intake, umm any other questions you can ask to try to help me out thanks Robert

01-30-2009, 01:24 AM	#2
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: backfire from passenger side Robert. Put the truck in gear, hold the brake firmly. Accelerate rather hard but not WOT. Does it pop rapidly and steadily? If it does, chances are real good you have a cam lobe that has worn flat. Do a compression test. If a cylinders reading is real low thats the one. To verify your findings, remove the valve cover and start the engine and look for a rocker that isn't moving much. If you find one isn't moving you have a cam & lifter job to do sorry to say. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

01-30-2009, 01:32 AM	#3
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: backfire from passenger side Bob, welcome to the board. I just saw your new here. If you wish you can call me and I'll walk you thru this and answer your questions as best as I can. If I know the answer I'll tell ya. If I don't I'll tell you that too. 518 581 1622. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

01-30-2009, 04:51 PM	#4
1974blazer Registered User Join Date: Jan 2009 Location: Tucson, Az Posts: 15	Re: backfire from passenger side Thanks mr james, well i tried what you have said and it just makes the tires burn out no popping at all, its just a normal pop from flowmasters, someone told me it might be the timing, or running rich, i have no cats., i have a point distributor, when i punch the gas it hesitates but when i lay off and just cruze it rides cool!

01-31-2009, 04:21 PM	#5
1974blazer Registered User Join Date: Jan 2009 Location: Tucson, Az Posts: 15	Re: backfire from passenger side i was in my blazer right now, when the car is cold it runs great and once it got hot it lags, i was talking to my friend and he said all this started because my carb was dirty, anytime i clean the carb out it runs good, i have a see through fuel filter and i see rust, could that be the cause of it? on monday in my day off ima check the lifters, im guessing its my carb, all this started happening once my carb was getting filled with rust, ima try using my friends carb and if it runs great, than i know what the cause is and im putting mine up for sale, what sux is that the carb is a tear old...

01-31-2009, 04:31 PM	#6
1974blazer Registered User Join Date: Jan 2009 Location: Tucson, Az Posts: 15	Re: backfire from passenger side i have a edelbrock 650 cfm performer, can you tell which knob is the air and which is the fuel? i think its running rich

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