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Dim oil light?

27 July 2007
Denver, CO
Well it's my very first NSX owner thread topic lol. :smile: On Sunday I drove the car over to the gas station to put some gas in the tank so I could run the car and test all the functions. Started right up, idled smoothly and showed ~4 on the oil pressure gauge. On the way back, I ran it up through VTEC and it pulled strong and smooth all the way up to the redline. When we got home, my gf noticed that the oil idiot light was very dimly glowing. It was so faint, I hadn't noticed it, but it was definitely on. Also, the oil pressure gauge was reading around 0. Water temp was perfectly normal and the car was idling rock steady. I could hear no valvetrain noise at all - smooth and quiet. I shut off the car and checked the oil level. It was clean and right at the full mark. Also, there was no sign of an oil leak anywhere in the engine bay or under the car.

Confused, I spent 2 days using the search button here on Prime and discovered that the oil gauges are notoriously bad on NSX's, due to failing sending unit/switch. Based on my research here, I think I have two issues. One is the low pressure reading after the car has warmed up. I think it is just a bad sending unit addressed by TSB 91-008, correct? None of the earlier threads however seemed to address a dim oil light.

To test the indicator, I turned the ignition to illuminate all of the dash lights and the oil light glowed full bright. So, I know it isn't a bad bulb or something. I then started the car, the pressure gauge read ~4 again, and the oil light was dimly glowing. It didn't get any brighter. Based on my earlier Honda electronics tinkering experience lol (88 Accord Lxi - college/law school ride haha), this sure smells like an electrical issue. The only question is is it the switch or the wiring? Which brings me to the question: what switch activates the oil idiot light? Based on my search button research, this is what I currently think - please correct if I'm wrong:

Oil pressure sending unit (by oil filter) ==> Oil Pressure Gauge in dash

Oil pressure switch (on oil cooler) ==> Oil idiot light in dash

Oil pressure sending unit (by spool valve) ==> ????

First, am I missing any switches? Second, has anyone else experienced a dim oil idiot light? From the above chart it looks like I need to replace the oil pressure switch on the oil cooler to fix the light, and the sending unit on the filter hub to fix the gauge. Am I right?

LarryB, RON98 and anyone else who knows this system, your advice would be most appreciated! :biggrin: Thanks!
There is an oil pressure sending unit on the oil cooler pedastal for the oil light. Since you gauge is ~4 AND the light is dim, I think I would change that sender first.

37240-P13-013 is the part number for the sender. If you want someone to do it for you, LMK, I will do it while you wait. It is basically an easy threaded mount, just unscrew the old one, screw in the new one:).

The sender is about $20.

Thanks Larry, I'll order and change it out - it is within my ability I think. Though, I may need your services later down the road when my gf allows me to take a hit off the go-fast crackpipe! :biggrin: Balance/blueprint, tilton fly, port match, valve job etc...one can only dream lol For now, I just want it running to OEM spec.