Sunday, June 27, 2010 - 08:05 am, by: Scott Wilkes(Scottywilkes)
if you have a break booster this is normal, thye will increase by a few revs due to when you press the pedal you deplete the vaccum in the booster, this then acts similar to a small airleak while it re evacuate the booster of the air.
How many revs is it increasing? It should only be a couple hundred at most
Sunday, June 27, 2010 - 07:12 pm, by: Scott Wilkes(Scottywilkes)
driving you wont notice it mathew, at idle in neutral you will though, if you continue to rapidly depress the peddle you can get it to increase by near 1000 revs
Monday, June 28, 2010 - 06:15 am, by: Matthew Sharpe(Madmatt)
Yeah, I don't think 100RPM would be anything to worry about. Generally if you have a loss of manifold vac through an air leak, your car will idle rough. No idea how that applies to a turbo though - probably not at all as any vac lines for things like the brake booster would have to feed from before the turbo wouldn't they?
Monday, June 28, 2010 - 12:11 pm, by: Scott Wilkes(Scottywilkes)
there fed from the inlet manifold as post throttle body there isnt a negative pressure.
Next time you drive, hold some throttle and depress the pedal a few times, you will notice it goes hard like it does when the engine isnt running as there is no vaccum in the manifold.
Some cars run a vaccum canistor for such cases so they it can help this.
Diesels run a designated vaccum pump as they dont create vaccum in the manifold due to no throttle body
Previous
