| Did you ever replace the PCVs and hoses with the orifice with OEM parts? The fact that there was no effect when you removed the oil filler cap indicates the system has an opening somewhere else. Check the vacuum lines that go to the throttle body intake tubes. Did you ever get a different vacuum gage to verify the old one vibrating needle was the old gage or...? Sometimes vacuum gages will behave strange because they are a bourdon type design - operation is a curved brass bladder with one end fixed and the other end free to move as pressure or vacuum is introduced into the bladder. The free end in turn operates a lever that moves a rack with teeth that rotates a gear that moves a needle. A lot of stuff happening and a good chance for loose connections that will vibrate when tapped. But if a new gage still vibrates than it is assumed that the gage is ok and the vibrating needle is measuring internal engine vacuum pulsations. You could check your old gage on another car and see what happens. (in response to an earlier post in the old link) Although the engine is reciprocating and pulsing intake is the result, at 800 rpm the effect is essentially non existant in a good condition stock engine. Race engines with a lot of intake/exhaust valve overlap designed into the cam will however have reduced vacuum readings from stock and some needle vibs will occur at or near idle. But in the high rpms these engines are running the effect is necligable and not a concern to racers. Have you ever pulled the plenum? You may have vacuum leaks wher the injectors seal to the lower manifold due to dry and cracked insulators. I had this happen to me. Before I replaced all the injectors with the later type I had vacuum readings that were about 1"Hg lower than now (but not a vibrating needle).After replacing the plenum gasket and the injector insulators the vacuum readings increased by about 1"Hg. You could also have leaking valve guides - bummer. With plenum off you will be able to get better access to the EGR but it still is a PITA. I have never pulled or serviced mine. Have you run the compression and leakdown test ?
ZUL8TR in Orlando,FL |
