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Posted to Emissions Forum on 12/23/2012 5 Replies

Good morning everyone.

It doesn't happen to me as often as it did in my earlier years, but I still get annoyingly confused at a process that should be "cut-and-dry" ... an emissions inspection.

I have attached three different VIRs for the same vehicle, spanning a period of about 90 days. My question to you esteemed professionals is "Why are the Visual/Functional Sections so different?"

[1990 Nissan 300ZX 2+2, Emissions Infrared Data] [1990 Nissan 300ZX 2+2, Emissions Infrared Data] [1990 Nissan 300ZX 2+2, Emissions Infrared Data]

I think that I know why the October VIR had passing emissions: the tech entered it as a single exhaust and probed the right bank only, which is much cleaner than the left bank.

My MOTOR ECS says one cat, supporting the October "visual tamper" result. Alldata says dual cats, supporting the September and December visual "passes".

I had no trouble finding an EVAP pinch point and checking the ignition timing on this vehicle. What is with all the weirdness from the other two techs (or am I the weirdo)? And shouldn't a referee be a little bit more thorough at tracking down pinch points and timing specs? Alldata clearly spells out the procedure for checking AND ADJUSTING the timing on this vehicle (COP with adjustable cam sensor).

Aren't these tests supposed to be repeatable, to support the so-called "validity" of the CA STAR FuPR "calculation"? I (for one) am skeptical.

I know that you guys and gals can't see this car with your own eyes, but do you have any informed views about which of us is right or wrong? I believe that 2 or 3 of us messed up the test, and zero or one of us did it correctly. I promise that I won't be offended if you think that I'm one of the screw-ups; the STAR program long-term measure has already been there and done that.


Michael Barry
Quick Stop Smog & More
Sacramento, California, USA

Files Referenced:

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car Vehicle Data

1990 Nissan 300ZX 2+2 3.0L

Engine3.0 L
Trans5-speed Standard