If you are checking the O2 sensor output with it connected to a warmed
up engine, it should oscillate continually above and below 0.5 V.

Larry A.

George Thorburn wrote:
> Hi List,
>
> My 1.9 WBX is running rich. The motor runs fine but the plugs and exhaust system are covered with black soot. I have installed fresh plugs, I have checked the plug wiring, I installed a new Bosch green coil, I changed the temp2 sensor, there is a new Bosch cap and rotor. I put new vacuum connections to the fuel pressure regulator and the distributor as well as the other connections I could see. I have checked and cleaned the grounds from the battery to the transmission to the alternator to the coil and to the left head. The O2 sensor is showing about 1/2 a volt when idling and moves around when the speed of the engine is varied. If I cover the end of the exhaust pipe the engine will stall and the system holds the pressure so I am sure there are no exhaust leaks. I checked the timing and the mark on the pulley matches the middle of the case at idle (with the idle stabilizer bypassed). I have adjusted the air flow meter a couple of turns counter clockwise but it does not see
m to make any difference. To make things more confusing every thing was OK last summer, the problem seemed to start when I changed the coolant last fall.
>
> Any suggestions?
>
> Thanks,
>
> George
>
> '85 Westfalia
>