I am having idle problems, and suspect a vacuum leak. I purchased a the vac pump with gauge from O reily. Heres the dumb question. Where should I connect it to see overall vac the engine is producing. I uderstand how to apply pressure/vac to various places and see if it holds in order to check each line, but just how much vac should I have?
Dumb Question....Checking Vacuum
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88mouse
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Don't think a vac pump is going to help you much. All you need is the gauge to check it. Check it at the big line that goes to the vac tree on the firewall. I'm think it should be around 12inch's. A can of brake clean or carb clean is a good way to find a vac leak to.
Small vacuum leaks may not show much change using a vacuum gauge. The range of "good readings" varies so much from engine to engine that it may be difficult to detect small leaks. My engine pulls about 16.5" of vacuum at 650-7250 RPM, which I consider rather low. It is a mass market remanufactured rebuild, so no telling what kind of camshaft it has. Average readings seem to run 16"-18" inches at idle and 18"-21" at 1000 RPM. The only sure comparison is a reading taken when your car was performing at its best through all the RPM ranges and what it is doing now. Use one of the spare ports on the vacuum tree that is mounted on the firewall near the windshield wiper motor.
Use a squirt can of motor oil to squirt around the mating surfaces of the manifold & TB. The oil will be sucked into the leaking area and the engine will change speed. Avoid using flammable substitutes for the oil such as propane or throttle body cleaner. Fire is an excellent hair removal agent, and no eyebrows is not cool...
Use a squirt can of motor oil to squirt around the mating surfaces of the manifold & TB. The oil will be sucked into the leaking area and the engine will change speed. Avoid using flammable substitutes for the oil such as propane or throttle body cleaner. Fire is an excellent hair removal agent, and no eyebrows is not cool...
In case it is of any help or you start seeing weird readings, here's some depictions of various readings and causes.
Good luck.
Good luck.
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