914-6 Won't Pass Emission Test, (never does...*&$#@^$% bullshit) Options

[Eric_Shea]

I sent Rich some numbers via e-mail but I thought we should post here in case we have some answers that may help others. I just failed both HC and CO. Stock 2.0 six.

ASM Emmission Test

HC 15mph:
Max - 509
Avg. - 109
Meas - 573

HC 25mph:
Max - 469
Avg. - 89
Meas - 401

CO 15mph:
Max - 5.07
Avg. - 0.76
Meas - 10.17

CO 25mph:
Max - 4.97
Avg. - 0.77
Meas - 9.57

I doubt these guys even attempted a hand at the enrichment screws. I used to take it there all the time when the owner would actually wrench on cars (old P-car mechanic... not that old). Now it's just a bunch of melon heads with computers.

The guy took about 10 minutes to bring my car out and then said "sorry it took me so long... I didn't know how to start it" (IMG:style_emoticons/default/blink.gif)

So... lean it out and...?? (IMG:style_emoticons/default/confused24.gif)

I'm no good at this shit... thanks in advance.

[lapuwali]

Rules of thumb: HC falls rich to lean. CO also falls rich to lean, but falls faster than HC. So, CO is more sensitive to mixture than HC. If NOx is being measured, it RISES from rich to lean, until you're fairly lean, then it falls again.

On a carb'd engine with no cat, I'd expect HC to be no higher than 250 or so, and CO should be around 3%, more or less. You're so far above those numbers I'd say you're indeed rich, and probably not by a huge amount. It's possible you're misfiring, but I'd expect you'd be able to hear it. You can probably correct this with the mixture screws alone. At worst, you may have to go down a size on the idle jets, but you can probably squeak it under with the screws. Note that if you lean it out so much it's misfiring at idle, HC numbers can go up again.