Something odd
#1
Staging Lane
Thread Starter
Join Date: Jul 2006
Location: Atl. ga
Posts: 81
Likes: 0
Received 0 Likes
on
0 Posts
Something odd
I just noticed something strange on my car today. Sitting in car with it idling in park if I put my foot on the brake pedal and let off I hear the engine idle change. I can't see it on the tach though. The rpm goes up a little when I let off the brake pedal. Any of you experiencing this? Thanks.
#2
LS1Tech Administrator
iTrader: (3)
Join Date: Nov 2001
Location: Schiller Park, IL Member: #317
Posts: 32,010
Likes: 0
Received 1,462 Likes
on
1,054 Posts
The power brake booster is connected to engine vacuum via a line from the intake. There will be a slight change in engine vacuum when the brakes are applied/released due to a draw from the booster. This would explain a slight, momentary change in idle speed. Should be very, very minor though.
Can't say I've ever paid any attention to this on my Camaro, but I've noticed before on my Bonneville if I pump the brakes 3 or 4 times with the car idling in park the idle will jump around enough to even move the tach needle a bit.
No big deal really.
Can't say I've ever paid any attention to this on my Camaro, but I've noticed before on my Bonneville if I pump the brakes 3 or 4 times with the car idling in park the idle will jump around enough to even move the tach needle a bit.
No big deal really.