Question about Lamda Oxygen Sensor

[JFairman]

Originally Posted by Ronnie's.930

Ok and thanks. I will do this sometime today. And excuse my ignorance, but what is this going to tell me (for instance if the voltage numbers are within spec or if they are in the rich range)? Am I simply trying to verify that the engine is indeed running rich, as it seems to be, or am I testing to see if the O2 sensor is working? I'm a bit confused about this for some reason . . .

Thanks for your help, everyone!

By doing that you're just testing to see if the O2 sensor is good.

[Ronnie's.930]

OK - the O2 sensor is fine so I adjusted the idle mixture screw slightly leaner and the idle cleared up. I have an Innovate LM2 but have yet to install it (will do so in the next couple of days) so this adjustment was done by the seat of my pants. The car idles fine, runs great and pulls hard.

I do have an additional question, however:

While playing around with the idle problem, I noticed that if I hold the throttle between 3-4K, no load/while parked, I can hear some burbling and/or popping from the exhaust. It kind of sounds like deceleration popping when you remove the vacuum limiter valve (as I did years ago) but nowhere near the intensity (very minor). I would almost call this a "misfire" except for the fact that the car runs and drives like it always has. I don't know if this is new or not, as I can't remember the last time I held the throttle in this manner (years ago when I last timed it). I guess I am looking for comments regarding what other people's exhausts sound like in similar circumstances. I have a RarlyL8, non-Hooligan muffler that is about four years old . . .

BTW - when I noticed the "high rev burbling" I experiment with re-richening the idle mixture and there was no difference other than the idle went back to shat . . .

[Ronnie's.930]

Well, I got my LM2 back from Innovate and it is working great right now.

I wanted to use it temporarily, so I wrapped aluminum foil around the sensor wires and inserted the O2 sensor as far as I could into the tailpipe and muffler (Rarlyl8 with 934 stylecenter outlet so it went way in there - that's what she said ) and I was able to adjust the idle AFR to 13.2-13.3 and it now idles fine. I was fairly close to that via the "ear meter".

Maybe I will go ahead and hook this thing up and run with it. The big display sure is easy to read.