Oxygen Sensor

I have a 4.3, on my 89 Chev c1500.

Once my Engine warms up to about 110, the Service Engine Light
Comes on.

Temperature drops down to 100, and holds steady. However, Service Engine Light stays on for the duration of the drive.

I get a code 13, which refers to my Oxygen Sensor.

Does anyone have any ideas as to what is wrong ?

Thanks in advance for any help you can offer
Mike

check to see if it came unpluged or if the wire has come into contact with anything that may have burnt the wire. its possable that it just went bad.

thanks for you help ...

Assuming that it is bad ... what would happen if I just unplugged it ? Is it worth experimenting ?

Thanks again
Mike

if you unplug it, it will get a base reference from the computer, but your light will stay on at all times. they aren't hard to replace, and for most vehicles you can buy one for under 30 bucks.

thanks for your help ... I can detect no performance difference once the light goes on, but I'll take your advise and get a new one. Thanks again.

Mike

Very rarely does an oxygen sensor go bad. All it is is a messenger telling the computer if the exhaust is rich or lean, then they should switch voltage high to low 4 or 5 times a second. So with that said lets address your real problem.............. the 100 degree engine temp! what motor runs @ 100 degrees? the reason you are getting an oxygen sensor code is because the temp sending unit is telling the computer that the engine is cold..................... so it dumps lotsa fuel! thus the oxygen sensor is saying hey we are way rich down here I can't control it anymore so then you get a code. My guess is try a thermostat?

what temperature should the thermostat open (it appears to open at at 105~110 according to the gauge, then the engine temperature drops down to a steady 100), and you are right, it does appear to be sucking more gas than usual these days ...

Thanks for your help
Mike

The thermostat will open depending on the temp thermostat that is in the engine. For the summer, I run a 165F and in the winter I run a 185F which runs around 210F at operating temperature. Your thermostat may be stuck open or somone may have taken the thermostat out. A new thermostat and gasket costs like 8 dollars at autozone so replace it. The Thermostat cover bolts need torqued to 20 ft/pounds or 240 in/pounds.

I think I forgot something important ... I'm working in celsius !!! Forgot that my friends to the South work in a different system.

100 degrees celsius = 212 degrees Far.

So, it appears that my cooling system is A OK.

Perhaps its time to replace the O2 sensor then ...

Thanks
Mike