hi my name is kirby and i have a 1984 k5 blazer that i recently had a crate 350 from gm installed in. i got it back from the shop drove it around fine for a day, then the next day i get a random backfire somewhere in the engine compartment, now it does it everytime i drive it, once or twice before it gets to temperature, though once at temperature it will not backfire. i have all new wires and plugs and the entire hei distributor is new. any suggestions would be a great help.
CK5
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crate 350 backfire?
- Thread starter DKBusker
- Start date
gotblazers
1/2 ton status
what kind of injection system or carb does it have? Im thinking you may be running rich and until you get up to operating temp it cant burn it all. What does everyone think?
it is a brand new edelbrock 600 cfm that the shop put bigger metering rods in for some reason. it runs fine at idle and at cruising but every once in a while during slow acceleration it just backfires i guess. then once to temperature it runs like a top.
chulisohombre
1/2 ton status
you can adjust the choke to open quicker by loosening the adjusting nut and twisting if i remember clockwise to allow the choke to be slightly open and get more air.
wasted wages
1 ton status
Backfiring through the exhaust pipe, or thru the carb ???
Big difference..
zombie1969
1/2 ton status
Sounds like the choke could be ajusted wrong.I have no choke and need to take it easy till it warms up or it will lean backfire through the carb.
wasted wages
1 ton status
I call that popping back thru the carb.....not backfiring...well unless he has zoomies, the carb would be whats in the engine compartment
To me,,,, a backfire is what comes out the tailpipe with an extremely loud bang..and with headers they can ping pretty loud in the engine bay...
I was just trying to clarify....
DKbusker....I would look for a reason for it going lean at part throttle....
maybe a vacuum hose,, or a vacuum leak some where..
also check the vacuum advance in the distributor, make sure it works and the advance weights on the rotor are not rusted and stuck.
I agree with Wasted sounds like its running lean. I would go back to the shop that did the motor install and see if you can get the original metering rods. On the Edelbrock carburetor the larger metering rod will lean it out. Nice thing is it only takes 5 minutes to swap them out and you only need to pull the air filter to do it.
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Just another thing to look at is with the votec heads, I've pulled a intake gasket before and it can cause that to happen. Worth checking. I can dig up some pictures later if you need them.
