View Full Version : O2 sensor

08-16-2005, 05:22 PM
how often should an O2 sensor be replaced? Its been 3 years since ive replaced mine. Im getting almost no reading on my air/fuel ratio gauge. when I start the car the needle moves all the way up to RICH then it sticks just below STOICH and never moves again. shouldnt it be bouncing back and forth between rich and stoich at highway speeds? Ive replaced all the connecting wires and re-examined the sensor wire. There doesnt seem to ba anything wrong with them.

08-16-2005, 07:07 PM
i've never replaced an O2 sensor so i'm interested to know more about this too.

08-17-2005, 03:05 AM
That sounds like a healthy 02 sensor to me. I'm pretty sure the leds can't blink fast enough, so you end up with 2 faintly glowing ones. The sensor can also be slightly out of calibration, giving you a constantly 'slightly lean' condition on your guage. No worries though, the ecu can adapt to that. The sensor is dead when your gas mileage goes to hell and the ecu should throw a code. Narrow band sensors aren't useful as a tuning tool. :(

Sensor won't report accurately until it's warmed up. The ecu doesn't even look at it until then.

My 90 is on the original sensor at 100k. I get 31mpg if i can obey the speed limit on the highway.

Galek- its like replacing a spark plug in the exhaust pipe. Pretty easy.

08-17-2005, 09:03 AM
I am getting ready to put headers and a high flow cat on my car. Should I put the O2 sensors in or just use the old ones. They seem to be working fine.

08-17-2005, 04:36 PM
ok now I have a CEL... SO ill probably HAVE to replave my O2 sensor..unless anyone else has had a similar experiance.

08-18-2005, 02:23 AM
did you pull the code? is it the 02 sensor code?

Did you try resetting the ecu to see if the code returned?