Adjusting CO Level

[Decolliber]

The mechanic who adjusted the CO level on my Carrera today does not have an exhaust gas analyser. He did it using a multimeter attached to the oxygen sensor. I did not see whether he had it on resistance or voltage, but he said he could tell when the mixture was adjusted correctly by when the level fluctuated. Is this an acceptable way to adjust mixture? Can someone tell me what he was doing? This guy does not normally work on Porsches but has an enthusiastic following amongst the local BMW crowd.
In any case, the car idled much better afterwards.
I also put a brand new DME in my 88 Carrera and it runs much better now. Sold the old one, which was from an 84 Carrera (wrong part number for an 88).

[tobluforu]

Since he's not measuring exhaust gases, i would say that he's not measuring c o, but what do I know? What i do know is that this is the way that I adjust the mixture in my saab. First i adjust the resistance at the air mass meter itself. I then get the car to operating temperature and then check the voltage at the oxygen sensor. If it fluctuates at the range it is suppose to than i leave it alone. If not, then I adjust the air mass meter until it is right. Passes smog here in ca. with out a hitch. This is BASICALLY what he was doing but i don't think porsches have air mass meters.
Same theory, different car.

[stlrj]

"The O2 sensor is constantly in a state of transition between high
and low voltage. Manfucturers call this crossing of the 0.45
volt mark O2 cross counts. The higher the number of O2 cross
counts, the better the sensor and other parts of the computer
control system are working."


http://www.birrabrothers.com/tiger/e36/docs/all_o2sensor.htm



Joe