7747 convert to 4 wire O2 sensor

[Dieselsj]

Question about the ground wire specifically. D7 is the signal to the sensor, then D6 goes to engine ground. When converting to a 4 wire, do I just run the sensor signal ground back to D6 and eliminate the engine ground? Logic is telling me yes, but I know GM engineers weren't always logical.

[dave w]

2002 Vortec 5.0 liter _ 5.7 liter 4 wire O2 sensor wiring diagram attached.

dave w

[Dieselsj]

2002 Vortec 5.0 liter _ 5.7 liter 4 wire O2 sensor wiring diagram attached.

dave w

Thanks Dave. That confirms what I was thinking.

[dave w]

I'm not sure what to say about the "Resistor" shown in the "Low Reference" side of the 4 wire O2 sensor that is also tied to the case ground. Likely the 1227747 does not have such circuitry.

I like the 3 wire O2 sensor, signal to ecm, ground for heating element, and ignition 12 volts for the heating element. Most 1995 GM Pickups with 4.3 liter V6 have the 3 wire O2 sensor.

dave w

[lionelhutz]

Yes, if the element in the sensor is grounded. Basically, check the sensor itself from the plug wire (A pin?) to case is a short.

It's been a while, but I recall looking at the O2 circuit and finding it was a fully differential op-amp configuration when I did look at a schematic. I don't even know where to find the old ECM schematics anymore. Isn't the Ludis site gone?