O2 Sensor Readings
 

I don't know what is up with my O2 sensor system. The car has always seemed to run very rich. I installed DEFI AFR gauge onto the o2 sensor line directly from the sensor and the gauge would bounce between 17 - 14 - makes no sense.


Replaced the o2 sensor, same deal


The readings on my PFS Purple Box Controller show 83-88R at idle and when i let off the gas crusing it drops to 0-3L and comes back to 80-90R when applying throttle....also if I give half throttle at around 4500rpm the car breaks up like CRAZY and shoots major flames unless I punch it all the way

Your o2 sensor is just for cruising conditions, in which case it SHOULD bounce between 14 and 16. Stop relying on narrowband o2 sensors to tell you your AFRs.....

If your car is running rich under WOT, then you check the basics -- spark and fuel. Is your TPS set correctly? Spark plugs, wires, and coils good? Injectors good? Who knows how the PFS box is even tuned?

well i bought the narrow band afr gauge to see if my o2 sensor was functioning correctly under throttle

new plugs,wires, and fuel pressure drops off over the course of 2 hours to Zero - i assume this rules out leaky injectors


I know the PFS box is running in stock ecu settings as I know who ran it before me..

HERE IS THE ODD THING

if i try to subtract fuel from idle the car of course starts sputtering or stalls...but the o2 sensor reading still remains 83-88R?

Since you didn't seem to hear me the first time....narrowband o2 AFRs are WORTHLESS. You need a wideband sensor to adjust fuel, period.

1. The fact that your FP drops to 0 in only 2 hours indicates a fuel leak.
2. It doesn't matter what the PFS WAS set to, it only matters what it is doing on YOUR car.
3. Is your TPS set correctly?