I have a 960 that won’t pass smog, the car runs around 2% CO and 200-300 HC.
The O’2 sensor voltage hovers around .8 volts. I have tried everything to lower this reading. I created a vacuum leak; the voltage will start low and slowly end up at .8 Volts.

The car does have a failing engine wire harness. I have previously run new wires for each injector groups. (Ground and +) But this only stopped the stalling.

I have checked everything (car has new cat, new O’2, correct fuel pressure, no vacuum leaks, no fuel in oil, oil at correct level,) the list goes on. I know the O’2 should hover around .5 volts and swing fast. The reading I am getting is lazy at .8 V

One thing I do find weird is the O’2 reference voltage is at .8 volts, “O’2 disconnected and reading at the wire from the computer”. I have always found reference voltage to be .5V.

The next step is a new engine harness, $1500 part. I hope this cures a lot of the problems and hasn’t hurt the ECU. This will be my third harness on a 1992 960.

Thanks for any input.
Mark