Shorted Oxygen Sensor

RossKean · Aug 27, 2011

In my continuing saga of a very poorly running motorcycle (Crappy Running), I was reassembling and noticed that the wire for the oxygen sensor was pinched in the crankcase cover. Evidently squeezed tightly enough to cut through the insulation of the white wire. Can't be sure if it was grounding out or not. The wire isn't broken and I am planning to cover with electrical tape and then silicone sealant (can't use heat-shrink unless i want to cut the wire). This may have happened when we did the CCT change at Ed's Tech Day (NERDs Event).

I am wondering if a grounded O2 sensor could cause the symptoms I have been seeing? i.e. Very rich at idle, rough idle, poor fuel economy and no power below 2000 rpm. No diagnostic codes have shown up.

Thanks

Ross

joebiodiesel · Aug 27, 2011

It could give you problems if you shorted the signal wire to ground. The computer would add fuel in order to correct a lean condition (low voltage), but the engine wouldn't need all the extra fuel. The problem is that the white wire should be a ground, so it wouldn't make a difference if it was shorted to ground. So, no. Shorting the white wire to ground couldn't cause rich running.

Joe

RossKean · Aug 27, 2011

joebiodiesel said:
It could give you problems if you shorted the signal wire to ground. The computer would add fuel in order to correct a lean condition (low voltage), but the engine wouldn't need all the extra fuel. The problem is that the white wire should be a ground, so it wouldn't make a difference if it was shorted to ground. So, no. Shorting the white wire to ground couldn't cause rich running.

Joe

Bike is back together today and will be tested tomorrow. I'll post back to let everyone know. I hope that this is the problem. It was something wrong and was rectified - otherwise, I have a separate issue.

ross

RossKean · Aug 28, 2011

Bike back together with wire fixed. Runs smoothly now so apparently a shorted O2 sensor wire CAN cause fuelling problems. With all of the work I did on the bike over the past week, this wire was the only thing I actually fixed.

Ross

joebiodiesel · Aug 28, 2011

Glad it's fixed...regardless of why!

olsonm3915 · Aug 29, 2011

RossKean said:
The wire isn't broken and I am planning to cover with electrical tape and then silicone sealant (can't use heat-shrink unless i want to cut the wire).

In many cases, it is possible to non-destructively remove a pin from a connector, slip heat shrink tubing over the wire, and re-insert the pin. To release the pin, you may need a sleeve that fits over the pin, or a pick to depress a locking tang.

I favor the glue-filled heat shrink tubing which makes a nice strong waterproof repair. Another good option is self-amalgamating tape, also known as self-fusing or self-vulcanizing tape.

RossKean · Aug 29, 2011

olsonm3915 said:
RossKean said:

The wire isn't broken and I am planning to cover with electrical tape and then silicone sealant (can't use heat-shrink unless i want to cut the wire).

Click to expand...

In many cases, it is possible to non-destructively remove a pin from a connector, slip heat shrink tubing over the wire, and re-insert the pin. To release the pin, you may need a sleeve that fits over the pin, or a pick to depress a locking tang.

I favor the glue-filled heat shrink tubing which makes a nice strong waterproof repair. Another good option is self-amalgamating tape, also known as self-fusing or self-vulcanizing tape.

I have done all of the above at one time or another. Unfortunately, there are four wires inside a fairly loose sheath. All the pins would have to be removed from the connector and the sleeve removed etc. The electrical tape and silicone should hold it for now. The silicone ensures that the repair remains waterproof. The fusion tape would have worked for the outer covering but I didn't have any.

Shorted Oxygen Sensor

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Shorted Oxygen Sensor

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