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Just a quick question to the veteran motorheads out there. I am looking for a potential vaccuum leak and was wondering...if I gauge the intake, what "normal" vaccuum should it be pulling. In other words, how do I know if what I read is low? By the way...where is the best spot to tee into the system to get an accurate vaccuum measurement?
I don't know the vacuum you should read.
But, you might be able to find the leak by spraying ether (starting fluid) or WD40 around the vacuum lines.
The little red pipe stuck in the nozzle makes it easy to focus the spray.
One you hit the vacuum leak, the engine idle will change as it sucks the ether or WD40 into the intake stream.
"Normal" vacuum should be steady around 17-21 in-hg at idle.
You can tee into any conveniently located vacuum line that comes off the intake. Try to get as close to the intake as possible for most accurate measurements.
ether will work... but its not all that safe, if you use a little propane torch (unlit with the gas valve open) it is a little safer as propane is less volatile than ether, if you run it around a spot you think there might be a leak, you will notice the engine idle drop