R34 Gtr O2 Sensor Problem?

[sr20dettttt]

Hi,

Car is running rich and not smooth (acceleration, hesitation etc). I am thinking it's the o2 sensors.

My car is a r34 gtr and it currently has a power fc installed and tuned recently.

First question, when dyno tuning, do the tuners take into account the o2 sensors?

I decided to disconnect both o2 sensors and went for a drive, it feels perfect!

Second question, driving without o2 sensors connected, is it bad for the engine? (my car is running rich with the sensors connected anyway, i dont have any way to check air fuel ratios)

Thirdly, can I conclude that the o2 sensors are faulty?

Finally, I want to replace my o2 sensors anyway... I know I need the zirconia ones. Both sensors are they same right? Just different plugs? (One square, one oval?) Can someone please point me to a link or a place to buy a pair of them?

Thanks alot guys!

[breaker1845]

You should do some more searching as all those answers can be solved pretty quickly but I can summarize I guess.

1. You have a PowerFC so you should get ahold of the FAQ guide and you can actually go through the menu and check to see if your O2 senors are working from a Hand Controller. When Dyno Tuning, the sensors are either turned on or off basically as they are set to open or closed loop. When they are on they just trim fuel on cruise loads to increase fuel efficiency basically. Research some more if you want to learn more. If your tuner is good you can just turn them off and tune with the sensors and get the results you want anyway.

2. You can test oxygen sensors to see if they are faulty with a multimeter, if you get a very small voltage they are not working, forget what the actual range is. Search for how what values to look for a what wires (of the 3) to check.

3. You need the correct sensors for your GTR, which if it isn't a 32, you use zirconia ones. The 32 ones use a different composite and they don't work for the 33/34. Look up Kudos motorsport as they sell OEM senors. Could source elsewhere from Japan cheaper if you are keen. I wouldn't bother replacing them unless they are actually not working though. Do the test first.

4. Your car should be running rich (not excessive though) so if anything not having an O2 sensor would just make your fuel efficiency worse if it hasn't been compensated for by the tuner and you unplug the sensor. You might get fault codes and other stuff appear but there shouldn't be any real problems as far as I know.

5. Get a wide band for your car so you can measure and read AFR values while driving if you want. Very handy for tuning and detecting fuel issues that may occur. The PowerFC Hand Controller is very useful if you know how to use and read off it. Wouldn't suggest making any changes as they are only temporary from the controller anyway, but good to understand what you can monitor and see in case you have any problems that come up.

In short, you can just ask your tuner if he has it set to closed/open loop or how he set the tune up as he should know. Liked stated in the dot points, the car should run rich but not to a ridiculous point. If you have concerns after fixing/checking O2 sensors raise it with your tuner maybe.

Edited July 12, 2015 by breaker1845

[sr20dettttt]

Thanks for that! Haven't had the chance to talk to my tuner yet...

The thing is with the o2 sensors connected.. it is running excessively rich, as in... 250km a full tank on a r34 gtr.

WITHOUT the o2 sensors connected, it is running fine.. and I can see an improvement in millage already. (Haven't finish the tank yet)

I know that running rich is somewhat fine, I just don't want it to run lean.

Think what I'm really asking is.. can I just run my car with the o2 sensors disconnected till I can find new o2 sensors as a temporary fix?

[chiksluvit]

If it really is your O2 sensor, you can disable it via power fc hand controller anyway without having to physically unplug it

Some people here don't run O2 sensors including myself provided your tuner has done a good job.

My understanding is that closed loop is only applied during cruising and idle after car warms up, so it shouldn't affect your car too much if you disable it, unless your tune is really off in the cruising cells, which is unlikely but then again no one can confirm that except for your tuner

[breaker1845]

Check your PowerFC first to see if they are even switched on because if they aren't, unplugging them shouldn't do anything.

Also poor fuel consumption may not just be O2 sensors, other components can affect that too. But you did say you had some issues with hesitation and such that you believe is cleared once you disable the oxygen sensors.

If you have time, discussing with your tuner about your level of satisfaction or what you have discovered about the tune may also help if it was recently done.

You won't run lean disconnecting the o2 sensors either if that is your concern. You can order new sensors if you want from Kudos and they usually arrive at your door within a few days.

If the sensors are buggered (you can check readings from PowerFC or manually) then effectively if they are on and you disconnect them it would be beneficial, which I suspect could be your case.

[sr20dettttt]

http://www.ebay.com.au/itm/Front-NTK-OXYGEN-O2-SENSOR-NISSAN-R33-R34-GTR-RB26DETT-lambda-oxy-cyl-4-6-/111455121782?pt=LH_DefaultDomain_15&hash=item19f33e3176

Can someone please confirm that these are the sensors I need?

Front and rear sensors are the same but different plug design.

I need to order two of them, however because of the plug design, I have to cut and connect to existing plugs?

Thanks guys. Once I get a response, I'll order them right away.

[KiwiRS4T]

http://www.ebay.com.au/itm/Front-NTK-OXYGEN-O2-SENSOR-NISSAN-R33-R34-GTR-RB26DETT-lambda-oxy-cyl-4-6-/111455121782?pt=LH_DefaultDomain_15&hash=item19f33e3176

Can someone please confirm that these are the sensors I need?

Front and rear sensors are the same but different plug design.

I need to order two of them, however because of the plug design, I have to cut and connect to existing plugs?

Thanks guys. Once I get a response, I'll order them right away.

Check with your tuner first. When my Link was installed the O2 sensor was removed as the ECU takes care of the idle and cruise. You may not need to spend the money.

[R31Nismoid]

Never used O2s, only had them there to keep the Poleeece happy.

A decent tuner will tune better than what the O2 will provide in terms of "trim" etc. So go back and talk to them. Don't go spending money if you don't need it, and really, you shouldn't.