I have a 89 IROC 5.7TPI. I'm using the prominator to modddd

I have set my MAF tables more than 10% to make the car run rich. All my BLM's and INT's start off at 128 and climb to max while idle. If I tap the gas they go back to 128. I can not get them to go lower. The O2 voltage won't go over 50mV. I had the thing running so rich you could taste that gas comming out of the tailpipe. But, the ECU seems to think is still lean. I've tryed both closed loop and open loop. I just replaced the O2 sensor and the fuel pressure is 40+ lbs. The SES light is not on. Timing is set perfect. Car runs good and sounds good. The idle is smooth and smooth accel. It knocks and pings when WOT but, thats a story i've been working on for 6 months.
About 2 weeks ago the O2 was working fine and all of a sudden it when to 50mv and has stayed there every since.......

Is there a way to check my O2 circuit...??
What else should I try....???

The sparky plugs look normal (Not Rich Not Lean) and gap is still perfect........!!!

I'M confused....!!!!!!

 

Sounds like a faulty o2 sensor. I had a Bosch go bad after 2 months and the auto store said it has a one year replacement warrenty so you should have no problem getting a new one. Your o2 counts should be all over the place when the car is running as well as the mv s should be fluctuating up and down as you step on the throttle.

 

Yes, I would agree that your O2 sensor is bad.

 

Well I took the O2 back and exchanged it. The new one is doing same thing. I put my DVM on the o2 sensor with key on and not started. The voltage was 390mV. Then I started car. Voltage was around 440mV. I pluged sensor back in and damn thing started working.......

I still think it was a faulty 02....

Thanks for the help.