03-04-2005, 01:54 PM | #1 |
87 Wanna Be K30
Join Date: May 2003
Location: long island, new york
Posts: 218
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backfire... KA-POW!!!
what causes backfire on a carburated motor. the choke is unhooked and when the motor warms up it will backfire and lack just about all its power going down the road. mixture too lean? too rich? i cant even pull the truck out of the driveway. maybe the plugs arent fireing? double checked all the wires and they are all going to the correct cylinders.wires and plugs are all new. so is the cap and rotor. yea i think im lost
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03-04-2005, 02:00 PM | #2 |
Registered User
Join Date: Oct 2002
Location: Edmond, OK
Posts: 5,904
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sounds like your timing maybe off...
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03-04-2005, 02:21 PM | #3 |
In Progress
Join Date: Feb 2005
Location: Kamloops, BC, Canada
Posts: 312
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i had the same sorta thing, when it got up to a certain rpm it would backfire and gutless as hell. but it ended up being the collector gasket blew out
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1993 Chevrolet K2500 454 4L80E 1974 GMC 1/2t 2wd Stepside 305 auto *sold* 1985 Ford Mustang GT 5.0 5spd |
03-04-2005, 04:46 PM | #4 |
ROCKET POWER!
Join Date: Feb 2003
Location: Finland, Europe
Posts: 509
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It's running lean. You have a vac. leak somewhere, or the carb is not functioning properly.
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What did i do last nite? I had a wonderful time, That's what they tell me What did i do last nite? 1979 C-10 shortfleet: Olds 350, Th400, 12 bolt Current project: 1969 Olds 455 W-30, needing a rebuild |
03-04-2005, 05:47 PM | #5 |
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Join Date: Feb 2004
Location: Hodgenville, Ky
Posts: 735
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Backfire out of the carb is to lean
Out of the tail-pipe is to rich. But be sure your timing is correct too. |
03-04-2005, 06:01 PM | #6 |
STOP! Hamma time!!!
Join Date: Feb 2005
Location: Dallas TX.
Posts: 145
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Sounds like the timing to me. Did you put a Timing Gun on it yet?
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Plan your work and work your plan!!!, or pitty da fool!! 87 GMC BaseTrim, 305 under the wrench/TH400/ 92 Chevy 1500, 350,TH700R4 sittin on dubs |
03-04-2005, 06:09 PM | #7 |
Chevys Kick A$$
Join Date: Jan 2005
Location: Zootown, MT
Posts: 12,699
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Yeah, I was having the same problem and it was my timing. Either that or a vacuam leak.
-Later
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*HOODS is what I answer too* -'79, '77, '88 Pickup Sold, '85 Camaro, '83 T/A, '81,'83,'90 K5 Blazer All Sold -'79 3/4 ton "Big Yellow Bananna" Lifted 4spd. 39.5 TSL Swampers, The money Pit -'86 K5 Blazer Silverado 6.2 4" lift 35"s -'95 Ext. Cab Shorty 4" Tuff Country rolling 35" M/T's -'83 Monte Carlo T-Tops. 126,500 Original Miles -LATER I would rather push a Chevy then drive a ford!!
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03-05-2005, 12:00 AM | #8 |
Registered User
Join Date: Jan 2005
Location: Northern Vermont
Posts: 159
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did you check the carb gasket?
-Levi |
03-05-2005, 01:44 AM | #9 |
Registered User
Join Date: Dec 2004
Location: New Lenox, IL
Posts: 442
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I actually had my Q-Jet backfiring on me when it was waayyyy too rich just before I took it off. It was so rich that it was fouling plugs to the point where they wouldn't even fire within a week!! And it also lacked power like you say. But Yeah, It is most often like everyone else said-Lean or maybe a Vacuum leak. I have also heard of ignition modules doing that, but I'm not sure what setup you have.
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