Oil Pressure Gauge Troubleshooting

[flying2275]

I have a 1979 K10 with a sbc 350 and looking for some help troubleshooting the Oil Pressure Gauge.

With the key off the oil pressure gauge reads 0, when in run position with engine off its at 0, when the engine is started it goes to 60 and when the engine is shut down it goes back to 0.

I figured it was a bad sending unit so I replaced it with a ACDelco p/n D8032 but the gauge is still doing the same thing.

Is there any way to test the gauge before I replace it or is there something else I should be looking at?

edit: Forgot to add that I made sure the wire going to the sending unit wasn't shorting out.

 

[Camar068]

no fluctuation in the gauge while reving or under load? Does it go down at all once it warms up?

 

[flying2275]

no fluctuation in the gauge while reving or under load? Does it go down at all once it warms up?

It stays steady at 60 at all times.

 

[GTME94]

If I Google'd correctly that part number is a switch not a sensor. So once it reaches the set pressure it goes from off to on. You need a sensor which has a variable output. Looks like you need a D8050.

 

[Camar068]

Not that I've done it, but knowing how sensors work, you should read variable resistance at variable pressures on a sensor. Take an ohm meter to it (disconnected from the vehicle). It will fluctuate with none/more/less pressure to it. Just blow into it or use a syringe to put pressure on it. It should vary in readings. It should ramp up or down depending on the pressure put to it.

Your sending unit should look similar to this one:

You must be registered for see images attach

Not this one:

You must be registered for see images attach

 

[flying2275]

Not that I've done it, but knowing how sensors work, you should read variable resistance at variable pressures on a sensor. Take an ohm meter to it (disconnected from the vehicle). It will fluctuate with none/more/less pressure to it. Just blow into it or use a syringe to put pressure on it. It should vary in readings. It should ramp up or down depending on the pressure put to it.

Your sending unit should look similar to this one:

You must be registered for see images attach

Not this one:

You must be registered for see images attach

This is the sending unit I installed. https://www.amazon.com/ACDelco-D8032-Professional-Pressure-Switch/dp/B000IZ00PW

Ill try using my air compressor to read the ohms.

 

[87ChevyR10]

Somewhat related.

The wire running from OPG to sending unit is shorting somewhere. Which wire coming from the firewall is for the OPSU? My plan is to cut it and run a new one. As of now, the wire is disconnected from the OPSU and the gauge stays pegged out.

Thanks.

 

[flying2275]

Somewhat related.

The wire running from OPG to sending unit is shorting somewhere. Which wire coming from the firewall is for the OPSU? My plan is to cut it and run a new one. As of now, the wire is disconnected from the OPSU and the gauge stays pegged out.

Thanks.

On my 79 its a tan wire just like the one that connects to the sending unit.

 

[Georgeb]

You can work through the attached page and make sure your guage is working correctly. I would also be paying attention to the condition of the ground for the instrument cluster as well as the connections to the guage on the back of the cluster. Be sure the wire has no continuity to ground with both the sender and the cluster unplugged.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=25339.0

 

[flying2275]

You can work through the attached page and make sure your guage is working correctly. I would also be paying attention to the condition of the ground for the instrument cluster as well as the connections to the guage on the back of the cluster. Be sure the wire has no continuity to ground with both the sender and the cluster unplugged.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=25339.0

Thanks I sorta combined that idea with Camar068's suggestion up above and rigged a set up in the garage using a 12 volt battery and an air compressor. With this I was able to confirm my truck just has high oil pressure. I purchased it a few weeks ago not knowing much about its history other than the pile of receipts in the glove box that date from 95-02. Its only had 750 miles on it since 02.

You must be registered for see images attach

With 60psi of shop air applied. (That white paint smears very easily.)

You must be registered for see images attach

Made up a MS Paint drawing and hope it can be of help to others in the future.

You must be registered for see images attach