Nistune Forums

I have a R32 GTR with a R33 GTR engine which has the Zirconia sensors installed on it. With the R33 GTR ecu installed I was getting voltage fluctuations from 0.2v - 0.8v. All good. Plug the R32 GTR ecu with the nistune board installed and I'm getting 0.2v from the O2 sensors when the engine is warm but the voltage isn't fluctuating.

When I reinstalled the R33 GTR ecu I'm now getting 0.6v from the oxygen sensors and only one of the sensors is fluctuating and not within the same voltage range as before. It was about 0.4v - 0.6v.

Does any of this sound normal? I plan to tune the car off the wideband and not use the O2 sensors but I was curious as to what was happening.

Josh

All figured out. Idling doesn't get the O2 sensors going at least until you've done some driving.

I get normal o2 voltage fluctuation with the R33 GTR ecu. Plug the R32 GTR ecu with the base tune and I get a flat line that is about average of what a fluctuating voltage would be and they seem to be responding to throttle movements like the R33 GTR ecu shows.

I have attached a log of driving around with the R32 GTR ECU using the zirconia o2 sensors.

Is what is happening normal?

It should be swinging up/down when in closed loop

Have you got a log of the R33 GTR O2 sensor operation

I did have a log of the R33 GTR ecu in action, but it got corrupted, O2 voltage was swinging as I would expect.

Do you have the heater wire modification done to the R32 GTR ECU as per the GTR modification document on our website (Support > Installation documentation)

No.

The car is a R32 GTR with a R33 GTR engine and ecu so the earth for the O2 sensors is already in the wiring.

I have confirmed that the O2 sensors are indeed getting 12v with a multimeter at the O2 plugs in the engine bay.

So zirconia type O2 sensors create voltage in ralation to the A/F ratio, which I have a feeling is what I am seeing when the R32 GTR ecu is installed. The swinging voltage is from the change in A/F ratio, which is created by varying the amount of fuel the ecu injects to maintain average lambda.

Is it possible my R32 GTR ECU (with the Nistune board) is not seeing the O2 voltage?

Are you running an R32 or R33 loom?

Did you check the ground from the ECU also to the O2 heater ground?

From the notes:
So what we need to do is supply GND to the heaters so they operate the same as R32 - they're on whenever IGN is on. This is done inside the ECU by linking O2 sensor GND (pin 50) to the pin used for heater GND by the R33 ECU (pin 115).

The vehicle this document was based from Pete reports worked fine with reporting the signal (just slightly lower than the R33)

It's a R32 loom, just with a R33 ecu and O2 sensors. The only loom fiddling that happened was at the actual O2 sensor plugs, on the sensor side of the plug.

I've read the documentation. The R32 loom doesn't have the O2 sensor ground at ecu pin 115 (as you know), so the internal jumper does nothing.

I am getting 12v across the heater wires at the O2 and I'm getting the same voltage from the sensor wire at the O2 plug as nistune is seeing. I will also double check that O2 feedback is actually on.

I will check for continuity from the ecu ground to the heater ground just to be sure.

Yeah I'm not sure why it would not be working in this case. Pete indicated the R32 GTR circuitry seems to hold up some voltage (1V) to the R33 O2 sensors for it to work properly, and that the voltage was swinging in closed loop mode

When rich the sensor should be reading about 0.8-1.0 volt and lean 0-0.3 volts and in close loop swinging between them