Yes, one wire will be power and the other will be ground.
Yes, one wire will be power and the other will be ground.
Is the 4 wire O2 just have an extra chassis ground? So its not using the exhaust to ground the sensor?
The 4-wire has a sensor element negative or return wire that runs directly to the ECU so that it doesn't rely on the exhaust as the signal path.
Ok so where does the 3 wire O2 ground? ECM??
So far as I know it grounds the same as a one wire. case,exhaust,motor and then where ever the ecm grounds, usually the block.
6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF
Both have a connection between the negative of the element and the case of the sensor.
A 3-wire used the case for the signal path. The case connects to the exhaust, the exhaust connects to the head, the head connects to the intake and then the intake is connected to the ECM via a wire.
The 4-wire setup runs the wire that went to the intake directly to the sensor instead. It eliminates the possibility of a bad electrical connection in the exhaust pipes from causing false O2 readings.
What’s the best way to add a ground to the 3 wire O2?? Ground the exhaust somehow to the frame?
Change it to a 4-wire sensor. Then, find the negative sensor input wire and remove it from the engine ground and take it to the 4-wire sensor plug instead.
It would be pointless connecting the exhaust to the frame, since the frame isn't directly connected to the ECU.
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