Oil Pressure reads 20 PSI with ONLY IGN ON

Hey Guys,
Been a while since I have posted here! Finally getting back around to doing more Jeep work since my busy season is over.

I come looking for wisdom in regard to Oil Pressure Gauges. I have done a few Searches and have come up with nothing.

First, 1983, With a 1982 360 from a wagoneer.

I swapped out both the Oil Sending unit and switch (which I know doesn't have much use on stock CJ guages), as well as the Gauge. Got everything hooked up, but as soon as I turn on the ignition (not start the engine) I read 20~psi, once I start it goes up from there, and will vary with RPM, So I know it is working.. Kinda.

I know the Gauge works with resistance, and the less resistance, the higher the reading. Less resistance is the last thing I would imagine a 31 year old jeep would have. If anything I would expect more as I had to Butt Splice in an additional 6" of wire to allow the stock purple wire to reach the sender without burning on the manifold.

Any Ideas? Both ends of the circuit are new... I'm kinda stumped. I have seen a few "Calibration" posts, but that was primarily for fuel/temp not oil.

Thanks in Advance!

Unhook the sender and observe the gauge. If it goes to 0 with the key on there's an issue with the sender. If it stays at 20 there's either an issue with the gauge, or a short in the wiring, although usually a short will lead to a pegged gauge.

unhooked sender, IGN on, gauge reads 0.

Out of box failure on the sender?

Oh and it really reads more like 12-14PSI when connected.

I'd say bad sending unit or wrong model maybe.

Spieg said:

I'd say bad sending unit or wrong model maybe.

Click to expand...

I thought the same thing, the 360 out of the waggy, not being the correct impedance for the CJ Oil Gauge, however Morris 4x4 says it fits all CJ's WJ's with 2.5L, 4.2L, 5.0L, 5.9L

http://www.jeep4x4center.com/oil-pressure-sending-unit-3212004.html

Bad sending unit. Try the one for the CJ.

Randyzzz said:

Bad sending unit. Try the one for the CJ.

Click to expand...

It is the same part number/same part. Only different sender listed is for the 2.5 GM engine. Which this jeep did not have originally.

Guess its ordering another.

Might just try Napa or somewhere local if possible.

This may be of some interest;
http://civilianjeep.info/Strenk/Gauge%20web%20page/QuickFacts.htm

Spieg said:

This may be of some interest;
http://civilianjeep.info/Strenk/Gauge%20web%20page/QuickFacts.htm

Click to expand...

This is something else to check- might be a year model gauge issue-