My oil pressure gauge reads 15 psi 100% of the time while the engine is running I replaced the sending unit because it used to fluctuate and now it's just constantly at 15psi it's a 4.0l I6, any body else have the same issue or know what the problem is?

 

Have you verified actual oil PSI with a manual gauge? I wouldn't trust the dash gauge when trying to solve oil psi issues.

 

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This.

Get you over to Pep Boys and buy a Bosch manual gauge for less than twenty bucks. Use it as a temporary test instrument; no need to install it permanently. It should take you all of 5 minutes to connect it in place of your current sending gauge. Then you will know.

Knowing is good.

 

 

Check the wiring on the harness. Backprobe to read your resistivities. Post them here. Someone might know what the threshold is. You could have a bit of a short?, I'm guessing. I'd imagine an open would show full pressure.

 

What you really need to do IMO is see what it reads at a very hot idle. But yeah I would assume could be a defective sensor.

 

If you had bad oil pressure 2 years ago and didn't fix it, you would've known it.

Did you just get around to dealing with the issue? If the gauge in the Jeep reads the same as the manual pressure gauge, then you know it's working correctly. If the gauge reading is not correct, then there's a problem with the sender, the wiring or the gauge itself.

If you replaced the unit already, do you see accurate readings on the gauge now or not?

 

Mine does the same thing definitely a bad sensor. Those things are bad out of the box sometimes too. Check to see if the sensor is getting a proper 5v connection