Someone please help! I got a 1980 Toyota pickup longbed SR5 w/20R that is carbureted with CA emissions. I just finished a valve job, and the carb was rebuilt a few months ago. There are so many moving parts in this carb system I'm not even sure where to turn. Even the dealer didn't want to screw with it ... <img src="/forums/images/graemlins/frown.gif" alt="" /> Well it failed smog with the following readings: really good HC (way below avg), really good NOx (way below avg), bad CO (just above max).

Here are ideas/questions:
(1) Could the mixture adjustment fix all my problems? (2) Distributor/coil issue causing this? Should the advance diaphragm hold vacuum? (3) Air pump/air check valve symptoms? (4) There is no Oxygen sensor on this truck! (5) Could the timing chain be off by a tooth, but I don't really think so?

What throws me off is I expected high HC to go with high CO. Before the carb job it was running way rich. Any advice on where to look? Please any info is appreciated ...

Thanks,

John

Good HC = Good air/fuel ratio.

Good NO = Good EGR.

Bad CO (with everything else good) = Time for a new cat.

X2.
Converter could be bored straight through! <img src="/forums/images/graemlins/frown.gif" alt="" />

I found this info on diagnosing Cat/emissions:

http://www.aa1car.com/library/converter.htm