[urq] Failed emissions

Buchholz, Steven Steven.Buchholz at kla-tencor.com
Fri Aug 6 18:21:06 EDT 2004

... you could very well be right ... it may be that the cat is hollowed out
... if you still have the CO tap tube you can compare emissions before and
after the cat to be sure.  If the hardware isn't in too bad of shape it
isn't that difficult to unbolt the front of the cat, drop the thing down and
look inside with a flashlight ... 

... you could also have a point about the altitude change ... it certainly
wouldn't hurt to perform the mixture test/adjustment per Bentley ... and if
you find it is possible to improve the CO levels by ~1/3 go in and have the
car tested again.  If you don't know how old the OXS is, you might be able
to pick things up a bit by installing a new sensor.  

So, are they testing this car as if it had the stock WX engine, or are they
testing it to the specs of the 90 200?  If it is the former, I would expect
the MC engine to be a bit cleaner than a WX, so you may have something that
needs to be looked at.  I'd check the condition of the spark plugs to make
sure all cylinders looked similar, and do a compression test as well.  

I don't know how tough the emissions tests are in NV, but it used to be
possible to get an urq w/o cat to pass smog here in CA, but I suspect that
Smog Check II eliminates that.  In fact over the past few days I've noted
the fact I've seen a lot of not so old cars with the red paper number tags
in the window that indicate that they had problems passing smog ... 

Steve B
San Jose, CA (USA)
> 83 Urq with '90 MC2 swap.
> Chipped
> Nevada state emissions test: FAILED HC
> Engine speed: 2500 rpm      HC ppm allowable:  220     Acutal 
> reading: 388    
> Engine Speed:  800 rpm      HC ppm  allowable: 220     Actual 
> reading: 308
> CO% limits were 1.20% for both engine speeds, readings were 
> .52% and .64%  
> respectively.
> As best as I can tell the car has a CAT - I mean its there, do these  
> readings insinuate its hollowed out?  
> Its this something that can be adjusted to correct?  Does it 
> matter  that the 
> car just came from denver and is now at half the elevation?  

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