Quote:
Originally Posted by Samuel M. Ross
... with the engine shut down and the throttle minimum [not cranked up at the dash either] I found that I could pump it up to the pump's usual 15 to 25 but it would quickly drop and eventually go to zero. So in order to get a quantitative measure I timed the drop from 10-in to 5-in and this time was 25 seconds.
|
My suspicion is that this performance is not per design. The VCV will typically bleed off vacuum to a setpoint that is variable depending on rack position. Once this point is reached, the vacuum will remain at this level indefinitely if there are no leaks in the system.
With the results you have observed, I'd guess that the VCV is not completely sealed internally and is bleeding vacuum to the vent. While the level of the leak is not significant in this case, I don't believe that it's by design.