'86 coupe O2 test
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Joined: Jan 2006
Posts: 1,858
From: Lumberton, Texas
RE: '86 coupe O2 test
Well, really you shouldn't need it. 1st, you need to unplug your sensor, KOEO, check voltage on harness side of connector. GM sends a bias voltage to the O2 and measures reaction against it. Check for DC volts around .2v to .5v . If you are not getting bias voltage, then you have probably one of 2 things. Either there is an open to the ECM or the ECM is trash. Might need to pull the ECM out and do a circuit check from O2 to connector. Do you have a pin out of the ECM connectors? 
Joined: Sep 2007
Posts: 2
RE: '86 coupe O2 test
Old post but relevant.I just did the warm up test..after a few minutes the voltage from the o2 sensor moved up to about .68 to .71 and just kind jumped a little up and down from time to time,+/- .03v .I doubt the vacuum test with the brake booster line would work on a non MAF car,but I tried anyway and the voltage didnt move much.I then blipped the throttle same thing..not any real noticeable voltage increase.I then gave a quick,small spray of starting fluid and the voltage jumped a little to like.79v.The reason I'm doing this is the car is running rich,does this sound like the O2 sensor needs replaced? It's a '90 with about 110,000 on it.The voltage from the ecm was steady at .4v also
Thanx for any help
Senior Member
Joined: May 2007
Posts: 1,567
From: eastern NC
RE: '86 coupe O2 test
ORIGINAL: BigRed90
Old post but relevant.I just did the warm up test..after a few minutes the voltage from the o2 sensor moved up to about .68 to .71 and just kind jumped a little up and down from time to time,+/- .03v .I doubt the vacuum test with the brake booster line would work on a non MAF car,but I tried anyway and the voltage didnt move much.I then blipped the throttle same thing..not any real noticeable voltage increase.I then gave a quick,small spray of starting fluid and the voltage jumped a little to like.79v.The reason I'm doing this is the car is running rich,does this sound like the O2 sensor needs replaced? It's a '90 with about 110,000 on it.The voltage from the ecm was steady at .4v also
Thanx for any help
Old post but relevant.I just did the warm up test..after a few minutes the voltage from the o2 sensor moved up to about .68 to .71 and just kind jumped a little up and down from time to time,+/- .03v .I doubt the vacuum test with the brake booster line would work on a non MAF car,but I tried anyway and the voltage didnt move much.I then blipped the throttle same thing..not any real noticeable voltage increase.I then gave a quick,small spray of starting fluid and the voltage jumped a little to like.79v.The reason I'm doing this is the car is running rich,does this sound like the O2 sensor needs replaced? It's a '90 with about 110,000 on it.The voltage from the ecm was steady at .4v also
Thanx for any help
Exactly what all is going on with the motor, besides the rich burn?
And welcome into the forums there!
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