All,

I just barely failed the CO portion of the AZ emissions testing with my 89 2.6L. I just bought this truck so don't have any history on it but am wondering what the biggest bang for the buck is in reducing the CO level. I'll be looking at plugs, compression, fuel pressure tonight but am wondering if anyone has found a magic bullet like temporary mixture leaning, etc that works for these engines.

Randy

Bad O2 sensor, air injection pump not working, too far advanced timing, and a weak catalytic converter can all cause high CO.

By way of follow-up I got it to pass with flying colors last weekend. Although I replaced the O2 sensor and plugs, dist cap and rotor the culprit was actually poor timing. Like I said earlier I just bought this truck so didn't know much about it but the distributor lock bolt was a little loose and the distributor was slowly drifting to more retarded timing. When I put the light on it the reading was about 1 degree before TDC (really surprised it ran as well as it did)....so when I reset to about 12 before per spec it ran better and cut the emissions by 1/3 for the CO. I know you mentioned too much advance would affect CO negatively and that may be right but this was so far retarded that it just waa not cleanly and completely burning the fuel.

Anyway, the good thing about AZ emissions is you can use the first test as a diagnostic (for the $28 fee) since you get one free retest! :-)

Randy

So when are we going wheelin!?

Some of the Apache Junction boys have a run planned on the 29th of july... <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />