Oil pressure sensor / sending unit

[asylum]

Dear All,

My pressure gauge is sometime reading low values. When cold, values are ok (2 - 3 bar at idle, 4 - 5 bar when driving). Then after 10 - 15 minutes of driving, the values drop (0 at idle, 1 - 2 bar when driving). Then after 20 - 30 minutes, they are back to normal for the rest of the trip. It seems the sensor is ok when oil is cold and hot, but sending bad values when oil is lukewarm.

Do you also blame the oil pressure sensor ?

37245-PR7-A02 is the part number ? But what do you think of the SoS with the relocation ? Peronnaly, I do not like to add a flexible oil line.

Is it possible to access the sensor mount from below without needing to disconnect coolant hoses ? I know I have to take off the sensor with its mount.

 

[Old Guy]

That is a very strange failure mode. The gauge will read zero or low if there is a high resistance electrical connection so I would check the plug connecting at the sensor first to see if there is any obvious wiring damage that might be causing an intermittent problem. No point changing the sensor if its a wiring problem.

That is the correct part number. I can't comment on replacement because I am still using my original sensor.

 

[Honcho]

What an interesting issue. For certain NSXs, it's the gauge that fails. Others it's just the sensor. But in both cases, it always reads low. That said, the oil gauge system is not a model of precision. Some days, my gauge reads at the first hash mark when hot and other days at the second hash mark- identical conditions. I've always said if you want to know the real oil pressure, install a real race sensor and run it through a canbus.

I seem to recall @MotorMouth93 looking at replacing the OEM sensor with a fancy AEM and then running the signal through some kind of converter that hooks to the OEM gauge. Or maybe it was me LOL. My brain is getting old...

 

[asylum]

Yeah it is strange. The gauge never reads zero steadily meaning there is a faillure in the wiring. It fluctuates between 0 and 3 instead of 2 to 6 bars during 10-15 minutes when the oil is lukewarm.

And for the replacement. Is there an access from below without needing to pull out cooling hoses ?

 

[Chris_Lum]

Yes you can change it without removing any hoses. I have a DIY video for the SOS version in the DIY video subforum here. Be warned, there are some people that absolutely hate the SOS version because they say it's faulty. My gauge has read zero at warm idle before AND after the SOS unit. I do have both a new OEM gauge and new OEM sending unit ready to go in. I'm going to replace the gauge first to see if it fixes anything first. If no change, then do the sending unit just to see if that fixes the issue. Only then, can i really comment on how good (or bad) the SOS unit is.

 

[asylum]

Thanks then I will do this job this winter.

 

[SWFL_NSX]

My issues with low/incorrect oil pressure readings resolved themselves after sending the cluster off to Brian K for him to replace the capacitors. At the time I believe Brian said that nothing in his repair would influence the oil pressure gauge, but no other changes were made to the car and the pressure gauge has been reading correctly for 4 years now. If you haven't already replaced the caps on the cluster it's a good idea to do so regardless.

 

[Chris_Lum]

My issues with low/incorrect oil pressure readings resolved themselves after sending the cluster off to Brian K for him to replace the capacitors. At the time I believe Brian said that nothing in his repair would influence the oil pressure gauge, but no other changes were made to the car and the pressure gauge has been reading correctly for 4 years now. If you haven't already replaced the caps on the cluster it's a good idea to do so regardless.

I had him do my capacitors and no change to my oil pressure readings. Not sure if he checked anything behind the oil pressure gauge though as I never mentioned any issues in that specific area.

 

[Old Guy]

My issues with low/incorrect oil pressure readings resolved themselves after sending the cluster off to Brian K for him to replace the capacitors. At the time I believe Brian said that nothing in his repair would influence the oil pressure gauge, but no other changes were made to the car and the pressure gauge has been reading correctly for 4 years now. If you haven't already replaced the caps on the cluster it's a good idea to do so regardless.

Anything that alters the resistance in the oil sender circuit will alter operation of the gauge. If the connector at the cluster had 'issues', the simple active of unplugging it to send it out for repair and plugging it back in might have fixed a dodgy connection problem. Perhaps Brian K did a general clean up on the cluster.