Backfire Problems
08-28-2009, 11:19 PM
#1
Upper Middle Class
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Join Date: Aug 2009
Location: Wyoming County, West Virginia
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Backfire Problems
Okay guys, I have a 1996 Ford F150 XL 300 6 cylinder, 5-speed, and it has 98,000 miles on it..... the temperature guage on my truck usually runs at the "N" on normal with it fully warmed up (i know i need a thermostat).... the other night, me and another buddy of mine was going to have a reving contest between the F150's.... he started his up and reved it up for a few mins and it sounded pretty good.... he told me to show him what mine had and i said all i had was a y-piped exhaust with nothing but the CAT on it.... i started it up and let it run for about 15 secs (to let the oil get all the way in the motor) and then i reved it up a little.... i let off, and reved it up kinda towards the redline lol right when it redlined, the exhaust popped so loud that it scared the crap out of both of us..... i was proud of the sound untill my truck idled back down to idling speed 
....when it hit idling speed, it was missing like a 
freight train for about 6-8 seconds and then it straightened back out..... the only thing i could tell, is it loaded up on fuel and thats what caused the backfire..... but what would be making it load up on fuel???? when its warmed up at normal temps, i can rev it a high as i want and it wont load up on fuel or backfire or anything!! 
....when it hit idling speed, it was missing like a freight train for about 6-8 seconds and then it straightened back out..... the only thing i could tell, is it loaded up on fuel and thats what caused the backfire..... but what would be making it load up on fuel???? when its warmed up at normal temps, i can rev it a high as i want and it wont load up on fuel or backfire or anything!!
09-02-2009, 08:49 AM
#3
Hi-Rev Motorsports
Simple answer....
if the engine was cold or has been a while since run then when you started it...it was still in the cold start cycle..this pours alot more fuel throughout the entire curve...when you revved it up to the redline there was either too much fuel for the plug to fire and the raw fuel went into the exhaust and was then lit off by another cylinder in the exhaust...
or you have a week spark system...
main thing DONT rev up an engine cold...you can do lots of damage...break rings, bend pushrods all kinds of nasty things...besides arent revving contest weak an immature...???
either case make sure the whle spark system is up to the task of the load...make sure the cap/rotor, plugs and wires are all good...from there it is only teh coil and then internal parts that make it do that....
if the engine was cold or has been a while since run then when you started it...it was still in the cold start cycle..this pours alot more fuel throughout the entire curve...when you revved it up to the redline there was either too much fuel for the plug to fire and the raw fuel went into the exhaust and was then lit off by another cylinder in the exhaust...
or you have a week spark system...
main thing DONT rev up an engine cold...you can do lots of damage...break rings, bend pushrods all kinds of nasty things...besides arent revving contest weak an immature...???
either case make sure the whle spark system is up to the task of the load...make sure the cap/rotor, plugs and wires are all good...from there it is only teh coil and then internal parts that make it do that....
