Re: [alfa] 164S smog

[webb.p@xxxxxxxxxxx]

> We recently had an engine rebuild on our '91 164S, more or less because it 
> would not pass smog in California and, in having to choose whether to sell 
> it as is (was) or fix it and keep it, we chose to fix it and keep 
> it.  After the rebuild, which included pistons/liners, it still would not 
> pass smog without a new O2 sensor and catalytic converter (it too was high 
> in NO).  After the cat was replaced the NO output was almost nil.  If you 

So you rebuilt the engine to replace the cat and O2 sensor?

> think your engine's in generally good shape, replace the O2 sensor and 
> check the cat and replace the cat if it's bad.  If your car still won't 
> pass, then you've got the big decision to make about rebuilding the engine

There are many reasons for high NOX as Brad pointed out.  A rebuild will not solve many of them.   There's no decision to make regarding a rebuild.   With proper diagnosis the problem can be found and corrected.   Based on your account you jumped right into a rebuild without finding the problem, which the rebuild didn't solve by your own account.   Why would you advise someone else to do that?

> Our GTV-6 also recently had an engine rebuild.  After the work was done and 
> the O2 sensor and cat were replaced, it passed smog like a champ.

Do you have a thing about rebuilding engines to solve all problems?

On a 164, you're fortunate to have OBD to tell you what's wrong.   Someone on the list can advise you how to extract the codes.  If no errors are present, do the checks that Brad advised.   Beyond that, take it to a reputable Alfa shop that know how to diagnose these things.   Even a BMW, Saab or Volvo shop can help since they use ML1.7 and ML4.1 systems.  It's EFI 101 to get EGO into comliance.   If the problem persists, you can rent a dyno shop with WB02 support to try and diagnose the problem.   As Eric advised, first step is to get a DMM across the NB02 to see what it's doing.

-Peter
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