Topic: Loss of power at certain RPM's
in Forum: C3 Engines
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Hi All,
My 68 L71 recently developed a loss of power between 2200 and 3000 RPM. The car idles fine and runs well once past the 2200 to 3500 RPM band. The car was running perfect up to the point of driving to a park, stopping, walking around for half hour or so. But when I came back to the parking lot I noticed the loss of power as soon as I started the car.
The plugs and wires are brand new and the carbs were newly rebuilt by Holley. After I noticed the loss of power I ran several tanks of new gas with gas dryer with no effect. In reading other post I now believe it might be electrical in nature, condenser, coil or the TI module. As far as I know all of these are original to the car. I would think a coil is either good or bad not intermittent at a certain RPM. My question is what should I replace first and am I right in my assumptions? Thanks.
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adjusting the fuelsupply at higher rpm ?
dunno how you call it.. but at the front of my holley i can adjust how much fuel gets in.. ( beside those 2 screws on both side) and on the back there is another "room" where the fuel gets in for the higher rpm range... but i am sure thee are guess around you can give you a better explanation.. in proper english :)))))))
art-corvette
dunno how you call it.. but at the front of my holley i can adjust how much fuel gets in.. ( beside those 2 screws on both side) and on the back there is another "room" where the fuel gets in for the higher rpm range... but i am sure thee are guess around you can give you a better explanation.. in proper english :)))))))
art-corvette
when you start to lose power, do you get any type of pop,pop noise, does the car spit at all,,,sounds as if you are either experiencing a lose of fuel(maybe a fuel pump/filter/vapor lock) or a lose of vacumn,(a bad intake gasket)or if you still have a points distributor, ,,your points are breaking up,, check the dwell,,,should be 32 at 800 rpm,,,any questions email me direct at needdobx@aol.com,,rd
Lifetime MemberHOWELL, NJ - USA
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Sounds like fuel pressure may be overcoming a clogged line. LAst time the fuel filter was changed?
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Sounds like a carb issue to me. Might be a wee bit derty inside the main(center) carb. Once it gets past the transition from idle circuits to main, it starts to even out. You may have gotten a batch of poopy fuel, and it just stopped one of the circuits up. Just a thought.
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Thanks guy's.
To answer some of the questions raised. The car is equiped with the TI ignition so a points problem is out of the question. The filters in the carbs, they're the incert type within the carb body, are new with the remanufacture. I get no pop, pop or spiting it just bogs down through the 2500-3500 RPM range.
Thanks again.
i dunno how yuor holey looks like.. but i guess it won't be that different:
to check if there comes fuel into the chambers:
at idle your engine runs ok.. so i guess you won't have to check that ( open screw 2 on the carb when engine is running and the fuel should JUST A LITTLE overflow out of the whole.
since your prob starts at higher rpm .. i would suggest check the fuel at the "other chamber" .. open screw 3 with engine running and you should notice JUST A LITTLE fuel coming out. if not you can adjust at screw 4 to make more or less fuel getting into that chamber.
art-corvette
to check if there comes fuel into the chambers:
at idle your engine runs ok.. so i guess you won't have to check that ( open screw 2 on the carb when engine is running and the fuel should JUST A LITTLE overflow out of the whole.
since your prob starts at higher rpm .. i would suggest check the fuel at the "other chamber" .. open screw 3 with engine running and you should notice JUST A LITTLE fuel coming out. if not you can adjust at screw 4 to make more or less fuel getting into that chamber.
art-corvette
in Forum: C3 Engines
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