HELP! 305 poping throught carb HELP!
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HELP! 305 poping throught carb HELP!
Ive got a 85 monte carlo with with a 305 and comp controlledQJet the issue i am having is that at high rpms and under wotit bogs a little and pops throught the carb. it has ac accell coil and accell super stock wires and a cherry bomb witch conects where cat used to be.with about 3 feet of exhaust hooked on
i have so many placesi havestarted
-ignition
-checked plugs all look good less than 2 monthes old
-checked wires all on good less than 2 monthes old
- checked rotor looked good
carb
- well aint much to adjust since the pos is comp controlled
- thought it might be becuase of rear flaps not opening adjusted and no change
- made sure all electrical conections were good
-checked vacumes to carb all goood
vacume line
- was up and down them no cracks breaks or leaks
- just replace cracked weather worn and brokenabout 2 monthes ago
so things i might have missed let me know
also other ideas i think it may be are
bad cam
bad valve
bad valve spring
let me know any help would be great right now
i have so many placesi havestarted
-ignition
-checked plugs all look good less than 2 monthes old
-checked wires all on good less than 2 monthes old
- checked rotor looked good
carb
- well aint much to adjust since the pos is comp controlled
- thought it might be becuase of rear flaps not opening adjusted and no change
- made sure all electrical conections were good
-checked vacumes to carb all goood
vacume line
- was up and down them no cracks breaks or leaks
- just replace cracked weather worn and brokenabout 2 monthes ago
so things i might have missed let me know
also other ideas i think it may be are
bad cam
bad valve
bad valve spring
let me know any help would be great right now
#3
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RE: HELP! 305 poping throught carb HELP!
94xxx so could be 94 194 or above but the way it drives and handles and since im in minnesota and was origionall a texas car im going with 194sorry no idea if it's been rebuilt or replaced in the past
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RE: HELP! 305 poping throught carb HELP!
Backfiring thru the carb indicates the intake valve(s) aren't completely shut during combustion for whatever reason.
I doubt a wiped cam is the problem.
A bad intake valve or weak valve springs is possible too. They could be bouncing under high RPM's.
Stretched timing chain is a good possibility too since it gets worst under heavy pressure.
I'd check things out with a timing light first. Then do a compression test.
If you suspect slop in the timing chain test by putting a socket on the bottom pully and see if your getting any movement on the crankshaft that isn't immediatelymoving the camshaft.
I doubt a wiped cam is the problem.
A bad intake valve or weak valve springs is possible too. They could be bouncing under high RPM's.
Stretched timing chain is a good possibility too since it gets worst under heavy pressure.
I'd check things out with a timing light first. Then do a compression test.
If you suspect slop in the timing chain test by putting a socket on the bottom pully and see if your getting any movement on the crankshaft that isn't immediatelymoving the camshaft.
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RE: HELP! 305 poping throught carb HELP!
k question with the botom line there what is the best way to tell if i have moovement on the crank and not imediatly at the cam with out tearing down the front of the motor
#6
RE: HELP! 305 poping throught carb HELP!
Had this issue with an 81 Chev P/U w/305. Pull the passenger side valve cover and look at the valves on the front 2 cylinders and make sure they are opening and closing. The problem with mine was worn cam lobe, which was common on the 305. It was a wornexhaust lobe so the exhaust valve didn't open and there was still pressure left when the intake opened causing the pop. Pop wasn't noticeable until opening the throttle a bit. I think you'll find your problem there. If not the pass side then try the drivers side.
Bud-Where in MN are you?
Bud-Where in MN are you?
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#10
Just got a hold of an 87 cutlass with a 350 in it. Set top dead center timing and tried to start it. Keeps popping through the carb no matter how u move the timing.
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