CO Mixture Setting

[North Coast Cab]

What should it be for a 3.2?

John

[ZOA NOM]

0.6% - 1.0% according to Bentley. It says "Measured at test port on front of catalytic converter, oxygen sensor disconnected."

[john walker's workshop]

i usually go about 1-1.2% with the oxy sensor unplugged, then plug it back in.

[stlrj]

My 86 runs best when set <0.6%. I find that >1% tends to kill the bottom end and makes it too easy to stall when taking off.

Joe

[jimbauman]

So how is this set and measured?

JB

[ZOA NOM]

Should be measured with an analyzer by a mechanic. The adjustment is hidden in the AFM body. It may have a plug over the allen adjustment screw.

[Por_sha911]

OK, are we talking O2 or CO? I have a printout of recent readings:
HC 79
CO 183
CO2 13.8%
O2 .8%
AFR 14.33%
This is with no catalytic converter or O2 sensor.

[ZOA NOM]

Now I'm in over my head. I had my mechanic do the adjustment before proceeding, so I'm not really familiar with the specifics of the measurements.

[North Coast Cab]

I used a friends LM1 to determine the AFR and then converted from there. Per John Walkers recommendation the AFR is now between 14.11 & 14.04 which equates to 1-1.2%.

John

[Jeff Alton]

John, tell us a little about the "user friendliness" of the LM1.......... Easy to use? Did you use one that goes in the tailpipe or uses and O2 sensor farther up stream??

Thanks, Jeff

[jimbauman]

I borrowed an LM-1.... I welded another bung in my "test pipe" (thus turning it into a real test pipe!) .. so I could get readings with the O2 sensor operating.

It was pretty easy to use, although the results would be much more useful if I had an AUX box and it was attached so I could equate lambda/AFR readings to RPM.

JB

[North Coast Cab]

Jeff,
The LM1 was still mounted in the other car, but we disconnected the O2 sensor on mine and replaced it with the O2 type sensor from the other car. We then directly connected a laptop to get a more visable reading of the AFR. We were able to expand it to full screen and have a dial and digital readout. Once we got it very close we could capture 30 seconds worth of readings and have the laptop calculate the average. Then we fine tuned. Awesome set-up for like $300. I think it allows 6 different inputs. It can record 45 minutes of data.

John

[hobieboy]

A dumb question - how do you convert AFT/Lambda to corresponding CO value?

thanks...