On Sat, 28 May 2005, Comboverfish wrote:

> > HC: 197ppm (limit 83ppm, FAIL)
> > CO: 0.16% (limit 0.46%, PASS)
> > NOx: 1220ppm (limit 893ppm, FAIL)
>
>
> Dan, I haven't seen the whole original post; are these readings at
> idle?

Those are ASM2525 (acceleration simulation).

> The limits seem rather strict for a 1987 vehicle.

Oh, I donno...I had a '65 car that would reliably pass emission
tests with similar limits. The guy's idle results and limits are

HC: 504ppm (limit 300ppm) FAIL
CO: 6.76% (limit 1.5%) FAIL

Those are pretty standard state limits for an '87 car, and he's flunking
them very, very badly.

> Lean misfire (very minor) is my immediate guess. I'm sceptical that
> the converter has failed to reduce NOx while still oxidizing CO like a
> champ.

If he's running lean enough to cause those readings, there won't be much
CO off the manifold in the first place, so the catcon won't have a big job
getting rid of it.

> > Time for some systematic diagnosis by someone who has considerable
> > experience with the carbureted Mopars of the mid '70s through late
> > '80s. Just throwing parts at it will get very expensive long before
> > the problem is solved.
>
> Hear, hear! Some research in his yellow pages for a shop that doesn't
> wince when he mentions his problem would be a good start.

He might be on the phone awhile. There weren't all that many techs who
could do a good job with these Lean Burn systems when they were current
and new!

DS