camaro55427

anyone try or have done a 3 wire heated o2 sensor swap on a tbi

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golden

These are usually used on OBDII gen cars . Why would you want a heated O2 anyway ?

camaro55427

to run in closed loop

golden

Any car with an O2 sensor (1 2 or 3 wires) should run in closed loop .

RFmaster

'55427

It is an easy swap, and worth while if you are running headers and if NBO is sitting after collectors. In my case I run four wire NBO (AFS-75), the extra wire is used to provide true NBO ground reference back to the ECM. Separately powered relay is used to turn on NBO heater.

//RF

camaro55427

thx for ur help RF ill try it out

dwillis

I was told to run one when I did my 5.7 swap wiith headers...the car would run rich until it warmed up now it does better but I still have a few bugs to work out....Good luck

JeepYJv8

I just tried te same thing!!! i have a 350 tbi in a jeep. i have headers and a good flowing exhaust so i ran a 3 wire heated...

It is not working. neither would a single wire! im lost im in the process checking wiring but these 02's are a pain in the a**.

anyone know if i need to run back to the ecm ground? in theory i shouldnt have to.. but who knows

91RockS

I switched to 3 wire heated since 2 wire stock would not stay hot enough to run closed loop at idle. This is common with modded motors with headers. Used a Delco AFS-74 with plug and play harness from TPI_parts on ebay. You just have to run the ground wire to a good ground (back of cylinder head) and supply SWITCHED power. I tapped into the gray wire on the fuel pump relay for power, so the o2 sensor is only powered when the car is running. Works fine, no problmes with closed loop at idle.