pumping my brakes will rev my engine at idle
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From: Edison NJ
Car: 87 formula and 85 olds delta 88 2 d
Engine: 60's 350 holley carb and intake
Transmission: muncie 4 speed with centerforce
Axle/Gears: 3.42 99 camaro rear w/ discs
pumping my brakes will rev my engine at idle
my car has always felt sluggish to get going and start to bog if sitting at idle. but if i pump my brakes, no bog and idle picks up...i am running vacuum advance and whenever i unplug the brake booster line it always has suction.. what is going on?
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From: Saskatoon, SK, Canada
Car: '83 Z28, '07 Charger SRT8
Engine: 454ci, 6.1 Hemi
Transmission: TH350, A5
Axle/Gears: 2.73 posi, 3.06 posi
Re: pumping my brakes will rev my engine at idle
Brake booster hose SHOULD always have suction... its supposed to be hooked up to manifold vacuum - meaning its under vacuum any time the engine is running.
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From: Slough, England (near London)
Car: Camaro IROC Z28 ~ 1987
Engine: 305 Tpi
Transmission: TH700R4
Re: pumping my brakes will rev my engine at idle
This is correct, if it dident it would mean brake booster was faulty.
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Car: 1989 GTA
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Re: pumping my brakes will rev my engine at idle
sounds like a vacuum leak in the booster.
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From: Littleton, CO USA
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Sounds to me like the idle circuit is too rich.
When you let off the brakes, a fresh shot of vacuum is applied to the booster diaphragm. That means some air enters the intake manifold via the booster vacuum line. If you pump the brakes, that sends pulses of air to the intake manifold. If RPMs rise when you do that, it means it's getting a more optimal air/fuel ratio at that time - meaning it isn't optimal other times.
Adjust your idle mixture.
When you let off the brakes, a fresh shot of vacuum is applied to the booster diaphragm. That means some air enters the intake manifold via the booster vacuum line. If you pump the brakes, that sends pulses of air to the intake manifold. If RPMs rise when you do that, it means it's getting a more optimal air/fuel ratio at that time - meaning it isn't optimal other times.
Adjust your idle mixture.
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