I've been tossing an engine code 64 on my 1992, which seems to be right O2 reading lean. The tailpipe on that side of my bumper would indicate rich, if considerably more soot than the left side is any indication. It is a safe assumption that this is likely an O2 sensor issue, or is there a way to take the injectiors apart and inspect their cleanliness? Seems to me that excessive soot would indicate the car us riching out the system in response, as one would expect.

 

I think you're on the right track, I'd replace the sensor.

 

If they are both older O2 sensors you might want to replace both of them at the same time. O2 sensors have a limited lifespan and when they start to go bad it takes a while for the driver to notice. The older worn out sensors don't have the same voltage peaks that a new sensor can deliver and on top of that they take longer to get the signal to the ECM as well. When the O2's go bad and are ignored the catalytic converters are next in line as the rich running engine will plug it up in a hurry.

When I first started playing with O2 sensors they told us to replace them every 24 months or 50,000 miles. The O2 is one of the most often ignored source of problems in the C4's fuel system. The engine needs air volume data (from the MAF), mixture data (from the O2) and the engine coolant temperature sensor for the primary fuel system calculations. Any one of these will cause you grief, Both the MAF and the O2 were designed and intended to be replaced where as the CTS is a bit harder to access under the throttle body. Just this morning there was a guy who has a bad CTS making his car drive around with the (choke on) burning extra fuel thinking the car was actually cooler than it was. Of course there is no choke, Cold Start Fuel Enrichment is what they like to call it but it does the same when the ECM is being told it is 20* outdoors when being driven. It will affect your mileage in a hurry and the fuel will end up as carbon in your catalytic converter.

Today the recommendations have changed with the newer better O2's they are making. A lot of cars use 4 O2's like my Wife's VW and that gets expensive. I would still replace them in pairs myself if I had to. I had to buy four for my son's VW and one of the four was defective from Bosch.

Keep the cover on the New O2 Sensor to keep it from getting exposed to anything. Right before you install the O2 is when you should remove the cap and screw it in.

Good Luck and your car will be much happier afterwards!
Chris

 

Yeah I've got two replacements. The right is easy enough to get to, I don't want to dick with the left until fall if its not giving errors, I've lost enough of this summer with the car in the air being repaired instead of driven!