4 wire O2 sensor wiring with MS3.57x and relay board?

[cgill]

Okay, this may be obvious but I can't seem to figure it out.

I have a MS 3.57x system with the MS relay board. I originally had a 4 wire narrow band oxygen sensor wired to the relay board (O2 terminal, 12 V switched power, and CLT rtn for the two ground wires). But now I have switched to a wide band FAST (Fuel Air Spark Technology) oxygen sensor and the associated connector. The connector has four wires: One is ground, one is 12V switched power, one is air/fuel sig +, and the other is air/fuel sig -.

Since there is only one O2 terminal on the relay board I am confused as to where the air/fuel sig + and - wires go in the MS system. I did a search on Google as well as this forum but couldn't find an answer so any help is greatly appreciated!

Chris

[thedrew]

MS wants a 0-5v signal. What exact model do you have?

pull out the DMM and see what output gives you a 0-5v signal?

[cgill]

Sorry, what is a DMM?

I looked at the wiring diagram for the MS3X board and it shows 3 0-5V analogue in wires for #21-23.

It's a FAST O2 sensor processor kit part number 170579.

[thedrew]

DMM = multimeter, voltmeter, etc

[prof315]

Okay, this may be obvious but I can't seem to figure it out.

I have a MS 3.57x system with the MS relay board. I originally had a 4 wire narrow band oxygen sensor wired to the relay board (O2 terminal, 12 V switched power, and CLT rtn for the two ground wires). But now I have switched to a wide band FAST (Fuel Air Spark Technology) oxygen sensor and the associated connector. The connector has four wires: One is ground, one is 12V switched power, one is air/fuel sig +, and the other is air/fuel sig -.

Since there is only one O2 terminal on the relay board I am confused as to where the air/fuel sig + and - wires go in the MS system. I did a search on Google as well as this forum but couldn't find an answer so any help is greatly appreciated!

Chris

Air/fuel sig + goes to the O2 terminal as as that is the actual signal air/fuel sig - is the signal return so it goes to a ground in the MS

[cgill]

Okay, just to verify, the O2 sensor 12V switched wire goes to the same power terminal as before on the relay board, the Air/fuel Sig + goes to the O2 terminal on the relay board, the Air/fuel sig -, as well as the dedicated ground wire on the O2 sensor goes to the CLT Ret terminal on the relay board.

Is this correct?

Thanks again for the input!

Chris

[prof315]

Okay, just to verify, the O2 sensor 12V switched wire goes to the same power terminal as before on the relay board, the Air/fuel Sig + goes to the O2 terminal on the relay board, the Air/fuel sig -, as well as the dedicated ground wire on the O2 sensor goes to the CLT Ret terminal on the relay board.

Is this correct?

Thanks again for the input!

Chris

Close but not quite.O2 Sensor 12V ok, Air/fuel sig + ok, Air/fuel sig - ok O2 ground is the heater ground and as such needs to be grounded at the block or at the same place the relay board is grounded