TwinTurbo.NET: Nissan 300ZX forum - I'm not sure intake vacuum is ok. Valves?!
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Subject I'm not sure intake vacuum is ok. Valves?!
     
Posted by Zarcasm(Hfd, CT) on March 30, 2009 at 9:06 PM
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In Reply To That vacuum reading at idle is good. The vibs occured > posted by ZUL8TR on March 30, 2009 at 02:43 PM
     
Message It is true that I had to tap the gauge to get it to swing but once swinging it would gladly continue. The old gauge should have more wear and resistance than a new one. I will buy a new gauge but I expect it to swing even more. The question is, is this amount of swinging normal. It is afterall a reciprocating engine. To answer this question I'll try and check the fluctuations during engine cranking. Have you done this before?

Normally you ground the high tension wire off the coil to keep the car from starting but since the Z has coil packs I'm not sure how to turn off the spark and keep the car from starting. Any ideas?

If the fluctuations during cranking aren't consistent I think that points to a valve problem (which makes me very apprehensive). I've got an old compression gauge as well for if things continue in this direction. Do we have any reason to believe that a sticky valve could indirectly cause the ECU to run the engine rich? Maybe I'm being overly presumptuous?

Any ideas where these PCV hose orifices lead to? I'll buy the PCV + hose kit soon. Since access is a problem I imagine this isn't an easy job. Any recommendations in this regard?

I have checked the fuel pressure: checks good. How do you check for injector leaks? The RHS spark plugs show no gas remaining on the spark plugs. All RHS plugs being fouled equally points to a more general problem to me. One that's affecting all cylinders. With the balance tube in place I expect the LHS spark plugs to be charcoaled as well although I haven't confirmed that... yet.

What's the easiest way to get voltage readings off the O2 sensors? BTW, I should be receiving the Conzult software shortly which I hope will expedite some diagnosing.

Thanks for your continued support!

     
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