My oil pressure has been reading wierd. I just put in a rebuilt engine from Pineapple Racing, and everything was fine, idled and oil pressure were both good. I go and start it the next day, trying to find leaks, and notice that my oil pressure has dropped to like 5 lbs. I shut off the car and tried it the next day to see if it was some freak thing, but it wasn't. I gave it a rev and the gauge barely mover.

I know its not the guage because I tested it with a 150 ohm resistor and it read about 50 lbs and held it, which I believe is correct.

It shouldn't be the oil system because every time I plug the connector in it jumps to 30 lbs and then drops back down to 5-10 lbs. The oil cooler lines also are hard to squeeze and feel like they have pressure in them.

I hope its just the sensor, but with my luck its probably something more.

Any help is welcome.

'86 SE

 

You need a separate, mechanical gauge to verify good oil pressure. You can get one at a parts store. Thread it in where the stock sending unit is located.

You could have a problem with the oil bypass pellet. There is a writeup on how to shim it.

http://fc3s-pro.com/TECH/HOWTO/OTB/otb.html

 

If it is the oil bypass pellet, wouldn't the gauge read like 40 or so when I'm at 3k? Right now when I get it to 3k, it just sits at 5-10 lbs and doesn't move.

 

http://www.mazdatrix.com/faq/oring.htm

 

It could be either of the two problems, but sometimes the gauge goes seems to work erratically. It'll go up to 60 lbs at 2.5k and act normal, but then most of the time it just sits there. So when I'm driving it works like half the time and then doesn't the other half

Does that sound like something the oil bypass pellet or o-ring failure would do?

 

The sender on the block goes bad....This has happened to many...
Verify with a mechanical guage, then go further.
It its still bad you may have a front cover o-ring problem.

Rotry_pwr