nagata

While installing my lowering springs, I figured I'd put in an Auto Meter short sweep electric oil pressure gauge while the front end was off the ground. Installed the sensor in the threaded port just below the oil filter (used a 1/4"-1/8" adapter, used Teflon tape on the threads of both), ran the wires, grounded to what I believe is a good engine ground (chassis ground that a large wire coming from the engine block goes to, best thing I could find), and put power to the gauge.

I also did an oil change, new filter, 6 qts. 5w30. I tested the ground wire to make sure it was grounding, tested the power wire, all that. Fired up the car for the first time with the new gauge, no pressure for the first couple seconds, then quickly rose above 75psi. This was at ~2000 rpm. It came off high idle and the pressure dropped to around 75psi, but never lower. Blipping the throttle made the pressure jump a bit, as expected. I know the oil pressure is higher with cold oil, but this seems really high. Isn't the pressure supposed to be maybe 50-60 on cold idle, falling lower as the oil heats up? I haven't taken the car for a drive yet, still trying to do the rear springs, but I'm a bit concerned.

Is this normal and I'm concerned for no reason? If not, thoughts on the problem? Ground wire not being run to a good enough engine ground? Sending unit? Problem with my engine? The engine has just over 64k miles on it, maybe 3k since the PI swap was done (by the previous owner), been running great, no odd noises or any smoking.

cliffyk

Perfectly normal, once hot the pressure should be 20-45 psi at 1500 rpm. The pressure relief valve bypasses at 85 psi, however if the oil is quite cold you might see more than that...

ride4lyfe

mine did same when first started, once oil temp comes up the pressure drops

nagata

Alright, good to know, thanks for the input guys! Figures I was over-reacting, but it just seemed really high.

cliffyk

My early '90s Miatas used to hit over 100psi when cold.

FYI and added comfort the rated burst pressureof an average "run-of-the-mill" oil filter (the weakest link in the oil flow path) is 270psi...

nagata

Thanks for the further input cliffy, that's good to know.