I put my CJ7 back together after 5 years of sitting in pieces in my garage and when I fired it up it pegs the gauge at 80+ psi, When I turn the ignition on it zeros out then once running it pegs. I am not complaining if its high higher is better than lower but can I trust it?
Its wired to using the solid purple wire to the sensor.
Strangely enough my Jeep has the same issue. I just purchased the jeep a few months ago, and the oil pressure gauge, if it moved at all, just fluttered around aimlessly. As part of the sale, the PO gave me a new-in-box sending unit.
I replaced the sender this weekend, and now the guage sits right at 80psi whether the engine is idling or revved up. I assumed I just got the wrong sending unit, and it's not 'calibrated' to work with my gauge. The good news is that I know I have oil pressure now ;-)
(I'm running stock 304 V8 with stock gauges, the jeep is a 76 CJ7)
In the field (of heavy equipment) they are still highly trusted and used. I have never had anything but good luck with them. I would prefer American made of course but being made in another country does not make it a bad product. Obviously my opinion, so buy and use what you trust.
Way back, they were literally made like a fine watch, by the hands (no CNC!) of very skilled craftsmen. Now it is just a guy who loads a pallet and pushes the send button. LOL
Seems to me that there is a lot of chatter brands of gauges but what if the relief valve on the oil pump is jammed closed and the gauge is reading correctly?
I would put any old gauge on the engine and verify the PSI and then come up with a plan of action.