backfiring
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Junior User
Joined: Nov 2002
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From: albany ga
backfiring
when it ry to start up my engine it backfires out of the exhaust. then when it is idleing and i press the gas it backfires out of the carb. i have checked the timing, it is set right. i'm stumped on this one and i need some help.
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Joined: Jul 2001
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backfiring
Backfiring is almost always timing. Rarely ever is it a mechanical problem (though sometimes it's a timing problem created by a mechanical problem.. if that makes sense.) At some point you're getting a spark while an exhaust or intake valve is partially open. Your timing light may be showing you that everything is right on. If your cam is off a couple of teeth, you may not be and the light won't help figure that out.
Doublecheck for vacuum leaks. They can and will cause problems. If you don't have any, then I'd put it at top dead center, set the timing to 12 degrees and see how that works. If it still backfires, I'd be doublechecking the distributor to make sure there aren't any problems with it. I had a distributor that had a nasty habit of the rotor rising up and completely destroying the cap. It had problems keeping the timing set. Little wonder. Anyways, past that, the only place left to go is the timing chain and the cam/crank timing to ensure everything is straight up. If say, the cam is 180 degrees off there will be problems. Same for the crank.
Hope that helps,
John
Doublecheck for vacuum leaks. They can and will cause problems. If you don't have any, then I'd put it at top dead center, set the timing to 12 degrees and see how that works. If it still backfires, I'd be doublechecking the distributor to make sure there aren't any problems with it. I had a distributor that had a nasty habit of the rotor rising up and completely destroying the cap. It had problems keeping the timing set. Little wonder. Anyways, past that, the only place left to go is the timing chain and the cam/crank timing to ensure everything is straight up. If say, the cam is 180 degrees off there will be problems. Same for the crank.
Hope that helps,
John
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Joined: Jan 2003
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From: Balfour
backfiring
idle mixture is too lean,richen her up and you'll probaly be good to go
to do this there are two brass screws at the front of the
carb near the bottom, screw'em in to richen it up.
I like to adjust idle with the engine runnig until I like what I hear.
The best way would be to screw those screws in all the way,
then back the screws out a turn and a half or two turns,
start the engine,
if it runs rich( black smoke,rough idle) back the screws out evenly untill it produeses a smooth steady idle.
Its' fool proof idle setting, my 390 purrs like a kitten and I did
it all myself,with some good FTE advice of course.
to do this there are two brass screws at the front of the
carb near the bottom, screw'em in to richen it up.
I like to adjust idle with the engine runnig until I like what I hear.
The best way would be to screw those screws in all the way,
then back the screws out a turn and a half or two turns,
start the engine,
if it runs rich( black smoke,rough idle) back the screws out evenly untill it produeses a smooth steady idle.
Its' fool proof idle setting, my 390 purrs like a kitten and I did
it all myself,with some good FTE advice of course.
Senior User
Joined: Jan 2003
Posts: 451
Likes: 0
From: Balfour
backfiring
crap happens! especially when I get to work
springs shootin' outta the hood, dropping stuff in the wrong place,oil allover my parents driveway etc. allmost lost a
pencil in my cylinder head trying to measure stroke
try playing with the climate controll after you got the idle set,
if it has trouble stARTING or sounds too rich at cold start.
springs shootin' outta the hood, dropping stuff in the wrong place,oil allover my parents driveway etc. allmost lost a
pencil in my cylinder head trying to measure stroke
try playing with the climate controll after you got the idle set,
if it has trouble stARTING or sounds too rich at cold start.
Thread Starter
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Junior User
Joined: Nov 2002
Posts: 74
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From: albany ga
backfiring
took it to the radiator shop today and they said it would be better to get a new one because the old one was not worth fixing. anybody got any suggestions on what kind to get.
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Senior User
Joined: Dec 2002
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backfiring
No recomendations on a brand, but you want one with a good warranty. 5 years ago I shopped around, and at that time the best warranty I could find for the price was 3 years for a heavy duty one for my truck (3 row). It's still in there, and aside from the bugs stuck in it, it still looks relaitvely new!
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