RPMs shoot up when pressing the brakes?
09-14-2010, 09:43 PM
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RPMs shoot up when pressing the brakes? The car is a 76 vette and when the brakes are pressed the rpms shoot up to around 2500rpm but the car doesn't accelerate. The problem appears in drive but not neutral. Could this be a vacuum problem? What should be checked?
09-15-2010, 09:06 AM
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Either a leak in the vac booster (if it stays up in RPM
as long as the pedal is pressed) or a way over-rich idle
that the vac booster air surge temporarily comps lean
(if it's a transient over-rev tht goes away again while
pedal remains pressed).
as long as the pedal is pressed) or a way over-rich idle
that the vac booster air surge temporarily comps lean
(if it's a transient over-rev tht goes away again while
pedal remains pressed).
09-22-2010, 08:51 PM
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That defiantly sounds like a vacuum leak. I would disconnect the vacuum line from the carburetor to the booster and see if your RPM shoots up then put your thumb over the end and see if it drops this will defiantly tell you if it's the booster. your breaks probably aren't working as well as they should.
