EXPERINCING VACUUM LEAKS ON MY 1969 JEEP WAGONEER
2 Answers
aztec626bf answered 12 years ago
Sounds like possibly an intake leak, but here is a good reference for vacuum trouble shooting.......... You should get between 17-22 in. hg. depending on your elevation above 2000 feet MSL or mean sea level. To perform this test hook vacuum gauge directly to manifold vacuum. 1. Low steady needle usually indicates leaky intake, a leaky vacuum hose, late timing, or incorrect camshaft timing. 2. If reading is 3-8 inches low and fluctuates at that low reading suspect an intake manifold gasket leak at intake port or faulty injector. 3. If the needle has regular drops of about 2-4 in hg. at a steady rate the valves are probably leaking. (Perform a compression check). 4. An irregular drop or down flick of the needle can be caused by a sticking valve or an ignition misfire. 5. A rapid vibration of about four in hg. indicates worn valve guides. 6. Slight fluctuation of one inch or so indicates ignition problems. 7. Large fluctuation perform a compression check. 8. If needle moves slowly through a wide range check for PCV issues. Hope this gives you a good place to start and helps you figure it out.
there are also vaccum hoses. check the hoses and see if one is loose, or off. vaccum hoses will cause a vaccum leak.