Low Vacuum Issue

by **1040** » 23 Aug 2005 5:59

Hi guys, another question for the experts! I checked my vacuum with a gauge this evening, and I'm only getting about 8-9 at idle, but it goes up to 20-22 at about 2000 RPM. I've tightened the carb bolts so no leakage there. Any ideas? Thanks.

by **dave-r** » 23 Aug 2005 7:58

What duration is the cam? The longer the duration the lower the idle vacuum. This could have an effect on your emmissions test results in your other thread.

by **1040** » 24 Aug 2005 4:27

Not sure about the cam, but it doesn't sound lumpy. I just purchased the car and, given the mileage, the engine has probably been rebuilt.

by **dave-r** » 24 Aug 2005 7:34

Check that you have no vacuum on the distributor vacuum advance port to check that the throttle is closed enough for the idle mixture screws to work. Then adjust the idle mixture just rich enough to give max vacuum at idle. Then check power valve size and pick one 2" higher rating.

vacuum response