Oil Pressure

[warrenw]

NSX PTY .. did you ever get a resolution to this? Tonight I had a very similar situation ... actually, the light came on while I was on the highway so I ducked into the closest garage .. but the gauge moved with RPM and showed adequate pressure and I had no tappet noise and since I was about 2 1/2 hours from home I decided it was likely the idiot light and continued on. For the next hour, the light would slowly vary all over the map (from almost off to full on) although the oil pressure wasn't varying much. Finally, the idiot light started blinking so I decided not to chance it any further and stopped at the next town and had it flatbed'd 45 miles to the dealer.

When I got home I checked the electrical diagram and counter to your claim above, the idiot light is connected to a master module which makes it flash(as well as a bunch of other things that need to flash). However, the wiring diagram says that the gauge is connected to the oil pressure sending unit but the idiot light is connected to an "oil pressure switch" (the symbol seems to suggest it's either on or off) but doesn't say where this is...although the FAQ says that it's somewhere on the oil cooler. Did you happen to have a malfunctioning switch or did they replace the sender unit (and, if so, did that fix the problem)?

Reviving a very old thread.
I hate it when people ask me if I searched it.
I searched it.

Ian, My symptom is exactly the same. On the highway, Oil lamp flickered a bit very low intensity, then it came on full. Oil pressure gauge showed ok. but just to be sure, I stopped right away and dumped an additional litre of oil in the engine. I had a litre and a funnel in the trunk. It was dark, so I pulled into a service station and under light, oil level was fine. After a restart all was normal. Startup test, oil lamp on, once engine running, oil lamp off. All normal. I did exactly the same research and learned about the master module in the foot well as well. It didn't behave with as documented. no blinking, just as described above. I was driving in snow, I know the rubber boot on my switch is cracked and broken, so it may be that the oil pressure switch grounded out with moisture. That switch is in the right rear wheel well. (could that actually happen?)
I thought that maybe my instrument cluster might be the problem, so I pulled that and sent it to briank to have all the capacitors replaced. There really are not any capacitors in the instrument panel for that oil lamp. O well, that is done. I have ordered a new pressure switch and will replace this winter.

 

[The King]

What condition were your instrument cluster capacitors in Warren?

 

[NSX2398]

Reviving a very old thread.
I was driving in snow, I know the rubber boot on my switch is cracked and broken, so it may be that the oil pressure switch grounded out with moisture. That switch is in the right rear wheel well. (could that actually happen?).

Warren, for what it's worth, since that original post, I had a second incident on the way to NSXPO in Vegas. I went through a snowstorm outside Salt Lake City and it was near melting so there was a lot of slushy snow on the highway and the light came on. Moment of panic since there weren't any exits at the time and my pressure gauge wasn't working at that time. Eventually pulled over .. topped up the oil & stopped to eat .. light didn't come back on so I continued on and had the sender changed in Vegas. Don't remember the details but they said the sender wasn't in good shape .. may have been leaking like yours. I think Vegas was in 2010 and I haven't had any issues since so I suspect fixing your sender will solve your problems.
...Ian

 

[warrenw]

Uh ha moment.
I remember you replacing an oil sending unit at NSXPO. You were with your son.
I did t realize it was this switch, I thought it was the other pressure sender.

Snow may be the common thing here.


Thanks Ian.


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[NSX2398]

I did t realize it was this switch, I thought it was the other pressure sender.
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Warren, I should have been more precise in my wording. While I was in Vegas, I had the dealer replace the idiot light pressure switch which I believe is what you're talking about. At the same time, Chris (SOS) diagnosed the issue with the new SOS oil pressure sending unit that I had just installed and was causing the gauge to read zero. A piece of what looked like Hondabond had come loose and worked it's way into the pressure sending unit and was keeping it from detecting the correct pressure.

I also forgot to mention that in the last month or so, I've had issues with the idiot light coming on dimly usually when sitting at a light with warm engine and the idle seemed to be lower than normal. So I had the dealer check the idle adjustment but he couldn't adjust it enough to make a difference. After reading some other posts, I think the cure might be to spray in some carb cleaner. I'm at about 200k miles and don't think it's ever been done so probably time. But I just wanted to mention that the low idle can bring on a scenario where the light dims a few times and then starts blinking and doesn't stop until I restart the car and then it's fine.

...Ian

 

[96 NSX-T]

Mine has been sitting on 0 for over a year. I just check the dipstick every so often. All is good there. + I rarely ever get to drive it. One day I might get a new sending unit. It would be nice to have a gauge that actually worked. NO idiot light, just no needle movement.

 

[NSX2398]

Mine has been sitting on 0 for over a year. I just check the dipstick every so often. All is good there. + I rarely ever get to drive it. One day I might get a new sending unit. It would be nice to have a gauge that actually worked. NO idiot light, just no needle movement.

Maybe you don't drive yours enough to notice but although mine typically reads close to zero, on some days it will suddenly jump up to around 4 and then after warming up, it will drop off closer to zero again. An increase in RPMs will often also cause it to rise a bit .. but it never just sits at zero all the time like it's broken. It's almost like there's a temporary blockage in the pressure sensor or in the engine where it feeds the sensor. Nice to have the idiot light as a backup though.

 

[warrenw]

Warren, I should have been more precise in my wording. While I was in Vegas, I had the dealer replace the idiot light pressure switch which I believe is what you're talking about. At the same time, Chris (SOS) diagnosed the issue with the new SOS oil pressure sending unit that I had just installed and was causing the gauge to read zero. A piece of what looked like Hondabond had come loose and worked it's way into the pressure sending unit and was keeping it from detecting the correct pressure.

I also forgot to mention that in the last month or so, I've had issues with the idiot light coming on dimly usually when sitting at a light with warm engine and the idle seemed to be lower than normal. So I had the dealer check the idle adjustment but he couldn't adjust it enough to make a difference. After reading some other posts, I think the cure might be to spray in some carb cleaner. I'm at about 200k miles and don't think it's ever been done so probably time. But I just wanted to mention that the low idle can bring on a scenario where the light dims a few times and then starts blinking and doesn't stop until I restart the car and then it's fine.

...Ian

Ian
I finally got to replacing the mechanical oil switch on the oil cooler.
This turns on and off the oil lamp on the dash. I actually had all the caps replaced on my instrument panel, thinking that was the cause, but as you can see by the picture it was the oil switch on the cooler. My rubber boot over the switch was cracked and was actually holding moisture. On a wet snowy day, the oil lamp would flicker then stay on..
Wet rust conducts.

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[NSX2398]

Ian
I finally got to replacing the mechanical oil switch on the oil cooler.
This turns on and off the oil lamp on the dash. I actually had all the caps replaced on my instrument panel, thinking that was the cause, but as you can see by the picture it was the oil switch on the cooler. My rubber boot over the switch was cracked and was actually holding moisture. On a wet snowy day, the oil lamp would flicker then stay on..
Wet rust conducts. Sent from my iPad using Tapatalk

Warren, tks very much for the feedback. I've been out of the country but back now so it's on my list of things to do. Good to hear it solved your problem .. so probably mine too. This is probably one of those things that the designers of the switch never anticipated .. that we would be driving in wet snowy conditions and to design a more water-tight connection.

The other thing now on my list of to-do's is to replace refurbish the left a/c condenser fan motor. I did the right one a number of years ago so long overdue. I haven't checked the fuse yet but the motor is probably just toast. And with temps close to 30 C .. and increasing mosquito population, it's not going to be a fun job but I didn't discover the problem until just before we left.

 

[Old Guy]

Ian
I finally got to replacing the mechanical oil switch on the oil cooler.
This turns on and off the oil lamp on the dash. I actually had all the caps replaced on my instrument panel, thinking that was the cause, but as you can see by the picture it was the oil switch on the cooler. My rubber boot over the switch was cracked and was actually holding moisture. On a wet snowy day, the oil lamp would flicker then stay on..
Wet rust conducts.

Sent from my iPad using Tapatalk

The switch terminal looks like crap; but, the oil filter sure looks nice and shiny :smile:. As a little extra insurance, a large slather of grease on the terminal would help to deter rust formation in the future if the existing (or new) boot should develop a crack in the next 20 years. I like to use silicon dielectric grease because it is definitely rubber & plastic friendly; but, a heavy bodied petroleum base grease would probably do just fine