Oil Pressure Reading on Gauge - What's Normal ?

[wixer]

Took my car out yesterday and today and when it was hot the gauge is reading higher than what I thought was normal. I've only owned it for three weeks, so I'm still finding my feet with it. I'm now getting it reading around 4 with normal driving and 2 on tickover. Not overly worried but I'm sure it was lower previously.

Any thoughts ?

[goldnsx]

The oil gauge sender unit seems to show its age. I've replaced mine last winter and now have more consistent readings (£££).

[duncan]

Just wait until you hit vtec, the oil pressure gauge will slump, your heart will falter with the prospect of a lightened wallet.
However, in those classic words, they (may) all do that sir. The 'driver' for the OPG is electo-mechanical, operating like a wiper from a 1920s fuel tank sender, it's not very high tech and the reading on one OPG will not be the same as another OPG.

[Pride]

Joe.
Explain what happened to your gauge reading at the Ring.🤔

[Ozmondo]

Mine is so inconsistent..

normally it seems to sit between 4-6 on the gauge however when I was on track at the ring it read between 0-2! I put it down to dodgy connection or faulty gauge since my engine didn't implode..

Will invest in proper gauges next I think!

[Hagasan]

Mine is so inconsistent..

normally it seems to sit between 4-6 on the gauge however when I was on track at the ring it read between 0-2! I put it down to dodgy connection or faulty gauge since my engine didn't implode..

Will invest in proper gauges next I think!

I might be the sender not the gauge? Probably is but also the pressure will drop when the vtec switches...

[Ozmondo]

Perhaps, good point but since it still gets a reading I would imagine it is the gauge..Either way I was going to replace the gauges anyway. :)

[Nick Graves]

The oil gauge sender unit seems to show its age. I've replaced mine last winter and now have more consistent readings (£££).

Mine was quite scary today; it seems to be a tachometer...

Is this the part number I require

37245PR7A02 SENSOR, OIL PRESSURE £376.26

TIA!

[goldnsx]

Yes, that's the part no. I've ordered. But not at that scary price. :)

[Nick Graves]

:D

Thanks for that.

I posted it for a bubble; I'll try to get a more Acura-te quote elsewhere...

[darock]

SOS sells a replacement sending unit for a goos price. I swapped my old tired sending unit for the SOS unit and now get consistent numbers. Mine was also fluctuating between 1 and 6 ... sometimes 2 and 4 ... now with the new sending unit it reads between 2 and nearly 6 depending on rpm which seems to be about right.

Bernhard

[Nick Graves]

Do Fuq!!!

Just ordered OEM one for twice that from Acura...still cheaper than HondarapeUK!

[goldnsx]

I didn't know about the SoS one. Another victim here...now I have to persuade myself that it holds double the amount of years the SoS one does. :) Anyway, I've ordered a big load of parts so it wouldn't have make sense to buy one separatly at SoS.
I don't like the relocation kit SoS sells because if the hose lets go my engine, my wallet and myself are fu......up.

[darock]

I liked the SOS version because of the relocation. Its straight forward, just a peace of braided line. Its really well made. They even supply the pin and rubber sealing to reuse the oem connector and an oem O ring.

https://www.scienceofspeed.com/index.php/nsx/enpp/engine-sensors-gauges-accessories/scienceofspeed-factory-oil-pressure-sensor-upgrade-kit-nsx-1991-05.html

[goldnsx]

I don't want the added complexity because you hardly ever look down there where it's located. But good hint anyway.

[jaffaz32]

:D

Thanks for that.

I posted it for a bubble; I'll try to get a more Acura-te quote elsewhere...


see post No. 15 of my build thread http://www.nsxcb.co.uk/showthread.php?13981-Jaffaz32-s-Boosted-Stroker-Build/page2

The oil pressure gauge on the dash uses a oil pressure sensor which is off the front head i believe, well it's accessible by removing the throttle body. It is known to be faulty unreliable. Science of Speed make a upgrade and replacement kit.

There is another oil pressure gauge at the filter but that triggers the light on dash from memory.

[goldnsx]

Front head correct. I've changed it last winter. From my (bad) memory removing the throttle body is not mandatory. I've removed the coolant canister and the air filter housing.

[Nick Graves]

I'm sure that with time, some expletives and spillage of claret, I'll find a way in...thanks for the tips.

[darock]

I removed the air box completely with connection hose. Throttle body can stay. The coolant expansion tank can stay connecting. just move it up over the throttle body.
And there is THE TRICK ... I read it on Prime. There is one 8mm screw holding the wire harness right above the sending unit. Undo this screw and flip the harness on the other side of the bracket. It will stay there by itself. This really makes the difference if you brake your fingers or not, doing the sending unit swap.

Bernhard

[goldnsx]

If you mount the new sender the cable of it tends the get screwed, nothing you like to happen. So make sure the cable turns as well when you mount the new sender unit.

[Kaz-kzukNA1]

For early model NSX like 91 model, there is a possibility that not only the sender unit but also the PO gauge were faulty. There was TSB released for this.

On the later model, the sender unit was already upgraded and while some of the PO gauge were upgraded at the same time but not all of them.
Therefore, you may still have the old spec gauge.

There are mixed feedback on the aftermarket sender unit.
If you google using ‘oil pressure sender unit site:nsxprime.com’ , you will find lots of examples.

The most recent one here;
http://www.nsxprime.com/forum/showthread.php/197094-Help-from-those-with-oil-pressure-senders-at-the-pump


If you cut open the OEM sender unit, the mechanism is primitive and like duncan mentioned in his post #3, it’s like swing arm fuel tank level sender.

I have seen many sender units seeping oil from the tired o-ring that sits inside the mounting block.
I always replace it during the Eng Refresh but even when using the new o-ring, I’m quite surprised how thin the o-ring is considering the depth of the groove on the block and the high pressure it will see.
It’s not shooting the oil out so don’t think it will affect the pressure reading but still, not great.


Personally, I would use the pressure gauge on the dash as a reference only.
If you see enough oil on the dip stick, no red low pressure warning light and pressure gauge moves upward when at higher rpm, pretty much you are fine.

If you track your NSX regularly, you better monitor the PO and TO especially if you don’t have any extra cooling performance.
Depending on the shape of the track, I would be more worried about the Gbox oil temperature....

Kaz

[Nick Graves]

I hope I never see a red oil idiot light!

Though I admit, my complaint says more about my OCD than it does about the pressure in the engine.

[goldnsx]

The oil pressure gauge is a gimmick of the 80ies where every Opel Manta had one installed. An oil temp gauge would have been much more useful.

Noone is permitted to drive an NSX if he doesn't check the oil and water level every other fuel filling. :)

[Nick Graves]

I cannot actually remember putting oil in mine between services - I clearly don't drive it enough.

Feel better now it's clearly no longer hypertensive and especially not hypotensive.

I have to say though - unless you're obsessive, don't bloody bother - it's one hell of a job for something so simple/slightly pointless.

I did it with just the water bottle out of the way and the wiring loom partially unbolted, which is still somewhat in the way. But then I have girl's hands.

The worst part is actually getting the new one in at the correct angle for the fine thread to pick up, finding it and the o-ring several times due to gravity...there's just so much crap in the way - mostly bits of engine casting and that big loom for the VTEC/coil packs.