Another Oil Pressure Gauge Thread, but not what you'd think

[Boosted87Supra]

ALREADY SEARCHED

So I've had my '87 Supra for a few months now and the oil pressure gauge has never functioned. I've searched many a forum, but haven't managed to find anyone with quite the same symptoms as me. A little back ground, before I bought the car the HG was replaced w/ an HKS metal and ARP studs were installed. No problems there, though the speedo cable was damaged, I replaced it, though the OP gauge didn't work, even before I pulled the cluster.

What I've done:

• Installed new USDM style oil pressure sensor (as the engine is still the factory 7MGTE)
• Checked the wire leading to the switch, found it to be chaffed. Performed a wire repair.

After the sensor was replaced the gauge acted like it wanted to read, not showing 4-6 psi at idle, but the needle was not resting on the bump stop. Though as soon as I went to go drive the car it quit reading again.


After fixing the wiring issue the same thing as what happened after the sensor replacement occurred.


So the gauge isn't completely dead, but if you mess with any of its inputs under the hood it will act like it is going to work for a bit, but then doesn't.


Any ideas?


Thanks guys

[cre]

Are you sure the gauge is USDM? The wiring runs from the sensor to both the gauge and the ECU, check the wiring to the ECU. You might also try disconnecting the wire to the ECU in order to rule out a fault in the ECU.

[Boosted87Supra]

1. Cluster should be USDM, is there a part/serial # I can check to be sure?
2. So the wire goes from the sensor to the ECU/PCM and the gauge...interesting. So do you know what pin on the PCM connector it is? Also how does it go to both, i.e. is it one wire from the sensor that splices/splits somewhere in the engine bay? Or is the splice somewhere under the dash?

Thanks

[cre]

The guage for North American models will be one of the following part numbers: '86.5 to '88 83246-14690 or 83246-14790; '89+ 83246-14890 or 83246-14870 These should all interchange without issue.

The oil pressure signal branches at connector M1. See the here. I don't have a pre89 TEWD handy for reference and I'm not finding it in my MAFT Pro wiring diagrams I made for the pre89 7M-GTE... So it's possible it's mislabeled, one of the unidentified pins or that the pre89 GTE didn't use use that signal. Look for a yellow wire with a black stripe on the ECU's connectors.