Adjusting Mixture on Lambda CIS with CO meter

[don gilbert]

A lot of people disable the system by pulling the relay, a bad no-no, renders the Freq. valve inop, which creates a lean situation at wot, esp. if control press a little high. Most have been inop for so long, when you get the freq. valve working again, it does feel like 20 hp.

[Peter Zimmermann]

Originally Posted by Nickshu

My meter has only two wires, one green (to the plug) and one black to ground.

I have searched Ebay and the like for a three wire version but cannot find one. I asked my local FLAPS if they rent them but they don't even carry them at all.

I was able to set the mixture as Peter Z recommended. Set to 0.7% CO with the O2 sensor disconnected using my CO meter. Then when it was reconnected mixture was 1.2% CO. Seems to run fine at that.

Any leads on a three wire dwell meter...where to find one?

Good move. RoW SCs (w/o cat) have a slightly richer spec (1.0-2.0% CO) that is set with the smog pump disconnected. 1981> models run at optimum at the low end of the spec range, so you can actually tweak your mixture up to 1.0% if you choose. Yes, with SSIs measure out the tailpipe, and remember to always turn your adjustment screw toward rich (clockwise) before trying to make the engine leaner. Also, after an adjustment, always remove the adjustment tool, and rev the engine a bit, then let it settle at idle before taking your CO% reading.

[mca]

Originally Posted by don gilbert

A lot of people disable the system by pulling the relay, a bad no-no, renders the Freq. valve inop, which creates a lean situation at wot, esp. if control press a little high. Most have been inop for so long, when you get the freq. valve working again, it does feel like 20 hp.

Holy cow. I can't believe this. Mine won't run without the relay. I remember when it failed - went super lean, backfired, and died.

[mca]

I wanted to apologize to Nickshu and the rest of you guys for bringing up the "no oxygen sensor" issue. It wasn't my intention to go off topic like that. We can save that conversation for another time and place.

Nickshu, after you get everything sorted out would you mind logging some CO data while you are driving? I'm curious to see what kind of numbers you get while cruising and at WOT. It can be tricky keeping the sensor in the tailpipe though - I used painter's tape to keep the wire secured along the side of my car and down through my sunroof (also keeps sensor from hitting pavement if it falls out).

Thanks! Craig

[don gilbert]

If you mess with it, you can get it to run fairly well with out the relay, but as i said, you have no throttle enrichment after the 35 degree throttle switch.

[Nickshu]

I'm not sure if I can drive it with my Gunson gastester CO meter in the car. Don't think the hoses are long enough. If I had a dyno it would work...but I don't. I can't find the thread with the dyno data with O2 sensor unplugged vs plugged on a Lambda CIS car. It was in a recent post but the thread was not about CIS, it was about dyno and HP figures and the member mentioned it as an aside....

After reading Peter's post I want to go richen it to 1.0% with the O2 unplugged, then plug it back in.

I'll wait for my Sears engine analyzer Ebay special to arrive (thanks Psalt!) and check the dwell swing first.

Thx all!!

[don gilbert]

you can buy a dwell meter at radio shack, auto zone for 20bucks.

[Nickshu]

Originally Posted by don gilbert

you can buy a dwell meter at radio shack, auto zone for 20bucks.

Just make sure that it's a three wire meter.... Red and black to power and ground, green to the test plug lead. As psalt pointed out, many have had trouble with a standard two wire dwell meter not working properly, myself included.