Popping noise under floorboard - The 1947 - Present Chevrolet & GMC Truck Message Board Network

wilpitz · 08-16-2003, 12:16 PM

I just got a 1970 Chevy c10 truck for free and I am trying to get it to run better. In 92 my dad did a lot of work on it(stroker 350, mallory ignition, eddlebrock carb, hooker headers, etc..) and he only drove the truck for 800 miles since then. The truck now has 58,500 orig miles on it and I just replaced the carb due to the truck running on when I turned it off. When I step on the gas to go fast it will make a popping sound which seems like it is under the drivers seat and the truck almost stalls when this happens. I think that it might be the headers but I am not the best automotive person around. I am going to go under and check for a leak somewhere but does anyone know how to test this.

Any help would be GREAT!

Thanks,

Chad

CoryM · 08-16-2003, 03:49 PM

What you are hearing is a backfire in the headers. Probably means you have too much timing (which can also explain the run-on). Also, you may be running too rich making it worse. A lean backfire is usually out the intake and the truck will slow down immediatly. Id make sure the timing was good first, then tune the carb.
CoryM

dinnut · 08-16-2003, 03:52 PM

what cory m said is true. also check that the headers are tight.an exhaust leak on my 72 made it do that. good luck with the free truck. sounds like you got a good one. and yo dad made the right decision to buy one all those years ago.

08-16-2003, 12:16 PM	#1
wilpitz Registered User Join Date: Aug 2003 Posts: 1	Popping noise under floorboard I just got a 1970 Chevy c10 truck for free and I am trying to get it to run better. In 92 my dad did a lot of work on it(stroker 350, mallory ignition, eddlebrock carb, hooker headers, etc..) and he only drove the truck for 800 miles since then. The truck now has 58,500 orig miles on it and I just replaced the carb due to the truck running on when I turned it off. When I step on the gas to go fast it will make a popping sound which seems like it is under the drivers seat and the truck almost stalls when this happens. I think that it might be the headers but I am not the best automotive person around. I am going to go under and check for a leak somewhere but does anyone know how to test this. Any help would be GREAT! Thanks, Chad

08-16-2003, 03:49 PM	#2
CoryM Registered User Join Date: Dec 1999 Location: Surrey, B.C. , Canada Posts: 874	What you are hearing is a backfire in the headers. Probably means you have too much timing (which can also explain the run-on). Also, you may be running too rich making it worse. A lean backfire is usually out the intake and the truck will slow down immediatly. Id make sure the timing was good first, then tune the carb. CoryM __________________ 1970 heavy duty C-10 fleetside sport truck. Vancouver B.C. Canada http://www.geocities.com/chevroletc1070 "Take up our quarrel with the foe: To you from failing hands we throw The torch; be yours to hold it high." Lieutenant Colonel John McCrae, Canadian Army

08-16-2003, 03:52 PM	#3
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	what cory m said is true. also check that the headers are tight.an exhaust leak on my 72 made it do that. good luck with the free truck. sounds like you got a good one. and yo dad made the right decision to buy one all those years ago. __________________ 70 longbed 496/th400/Ford 9"



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