krahmlow

This is very strange (and an on-going saga). When I hook up my multi-meter to the O2 sensor on this car, I get a reading somewhere in the 124 millivolt range, going up to 300 as the engine/exhaust warms. With the AFM set as rich as it will go, I still can't get the O2 sensor to read 500 millivolts (it won't go over 300), which is what the manual calls for. Yet when I set the AFM as rich as it will go, the car runs like total crap, so the AFM setting is making some sort of difference. I've replaced the O2 sensor on this car within the last year or two and bench tested the AFM (which seemed to check out OK). Any ideas? I've also changed the DME temp sensor, changed the fuel filter, checked the fuel pressure, had the injectors cleaned and tested, replaced the ISV and the TPS, and replaced all vacuum lines and seals. What else is there?

KitCarlsonEMS

Are you using a high impedance (digital) multi-meter? If you are using the 20K Ohm analog meter that may be your problem. To properly measure the O2 voltage you need a meter with an input impedance > 1 meg Ohm.

krahmlow

Well, I'm using a cheap digital multi-meter. I don't see anything on here about input impedance, though. I could try to borrow another to see if that makes a difference.