It's smog time, and I am trying to set my PFC to run lean at 3000 RPM (no load) for the test. The problem is, no matter what changes I make, my O2 voltage stays the same. If I hold the engine at 3000 RPM, I get an O2 voltage of about 0.75. If I go into the Injector map and reduce the value for that cell, my O2 voltage doesn't change. If I go into the PIM and reduce the value at 3000 RPM, my O2 voltage doesn't change. I've gone so far as to set the PIM all the way down to 50% and the specific map cell to 0.5 at the same time, yet my O2 voltage doesn't change. Am I missing something here?

My O2 sensor seems to be working, because I can see it oscillating when I go into closed loop on the highway. Anybody got any ideas?

 

Closed loop lasts until about 3K. Try turning off your O2 control.

 

get a better o2 sensor like the NTK for tuning.

 

Chuck,

Yeah, I already tried turning off the O2 sensor control, and that made no difference. Besides, I don't think it is in closed loop during this test...I'm just revving it in neutral and the voltage is staying constant. I also tried putting the car into and out of gear, thinking that maybe it might be in some special mode when revving in neutral...that didn't work either.

Xph,

I'm not really "tuning"...I'm just trying to lean out my mixture at one point on the map...that is, revving in neutral at 3000 RPM. For this situation, I don't think it's necessary to have an accurate sensor, just a working one. It's not like I'm under load where I can detonate, I'm just trying to make sure that I'm not dumping a lot of extra fuel out of the tail pipe.