upgrade to 4 wire o2 sensor?

[stevealvey24]

Is it possible to upgrade to a 4 wire o2 sensor from a 3 wire? If so what all is there to be done? I'm thinking with the exhaust I have (very unrestrictive) my non heated sensor is not getting warm enough to function properly.

 

[Andy D]

2 of the 3 wires in the O2 sensor are heater wires. The 4 th wire is just a drain for noise.

 

[stevealvey24]

So the three wire is heated?

 

[adsm08]

Yeah, the oxygen sensor makes voltage depending on how much oxygen is around it. It is case grounded for the sensor itself and can give a signal with only 1 wire. The others are for a heater.

 

[Psychopete]

I was always under the impression that the 4th wire was an addition ground to prevent any bias from a poor ground to the exhaust. 3 wire is a heated o2 sensor. 2 wire is not.

 

[stevealvey24]

Well dang. I was hoping this might be idle issue. So here's another question. I have the ground from battery to block, ground to core support from bettery terminal. Ground from back of head to firewall, and ground from head to where y pipe bolts to manifold. Is this right or is not having a ground from head to frame really screwing things up?

 

[Psychopete]

Run a temporary ground to see if it resolves, if it's in question. at least you'll know

 

[stevealvey24]

I've been planning on but now when I get home its dark. I'm hoping my injectors come in and I can get it done Friday or Saturday. Hoping these new 15# accept injectors I bought smooth my truck out.

 

[scotts90ranger]

the 4th wire is the ground for the heater, I know from personal experience... apparently '90 was the switch year for 4 wire sensors and my truck was built in late '89 so it had a 3 wire sensor, before I knew any better I put what the parts store handed me on my truck. it didn't run good and got an oxygen sensor code, grounded the 4th wire and all was good... Comparing the wires going to the Bosch sensor I got from Napa to the Bosch sensors we use at work that I know what all 4 wires are for I saw that the 4th wire was ground for the heater.