Idle fluctuation when brake applied
#1
Idle fluctuation when brake applied
When the car is idling and I press the brake, the engine reve move up and down about 300 revs. Is this normal or a problem. the car idles rough.
#3
the idle will move a little bit because the brake is vacuum assisted, but 300rpm is a bit much.
check the large vacuum hose (about 1/2") running form the manifold to the brake booster for leaks.
when someone presses on the brake, listen for air noises aorund the brake booster as well to see if the diaphragm is leaking.
could also be the check valve on the booster line.
those are the most common places to see issues here.
last thing..
when you press the brake down, which way does the RPM move? up or down?
does it stabilize while you have your foot on the brake, or does it only go back to normal idle when you let off the brakes?
check the large vacuum hose (about 1/2") running form the manifold to the brake booster for leaks.
when someone presses on the brake, listen for air noises aorund the brake booster as well to see if the diaphragm is leaking.
could also be the check valve on the booster line.
those are the most common places to see issues here.
last thing..
when you press the brake down, which way does the RPM move? up or down?
does it stabilize while you have your foot on the brake, or does it only go back to normal idle when you let off the brakes?
#4
it stabilizes at the lower RPM if the brake is kept depressed and goes back when released
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