Failed NOx emission on 1990 80 series

Huw Powell human747 at
Tue Dec 24 23:21:06 EST 2002

I don't have any solutions for your emissions test issues, I just wanted
to be irritating about some of the things the shop said they did...

> The shop also jumpered to check the timing

Most people use timing lights, bu what do I know?  What I would like to
know is *what* they "jumpered" to check the timing?

> They also mentioned that they enriched the mixture a little which
> increased my HC from 1.889 to 2.194gpm.

You can't enrich the mixture on a working OXS car, as long as it is
within correctable range.  Right?  You can turn the screw, but all it
does is enrich or lean out the cold running mixture, when warm the OXS
control loop should prevent "enrichment"....

Oh, I would say, run some more of that fuel system cleaner to see if
that helps.

Huw Powell

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