is it normal for the car not to read oil pressure when the engine is runing. the car is a 90 NA. the car goes back and forward on me some days it read it some days it doesnt is this typical on rotary or no..... and yes the car has oil to the full line so its not that.

 

If you mean that the gauge shows zero oil pressure at times, no, that is obviously not normal. For the stock gauge, check the oil pressure sending unit and the wiring in that circuit. If you have an aftermarket gauge, check the same items and if it's a mechanical gauge, check the pressure fittings.

With a fully warm engine the gauge should show about 65 psi (+/- a few ) at 3K rpm and around 25-30 at idle. Mazda says 64-78 psi at 3K rpm using their test device, but I've not seen anything higher than 65 psi in the FC's I've owned, and the S5 I have now consistently shows around 60-62 psi at 3K rpm on an aftermarket gauge.

 

ok.. i drove the car yesterday and it read no oil pressure on the stock gauge i checked the wiring and it all looks good. i drove it today it read zero again during start up and short drive

 

i drove the car again checked the filter and touched the oil cooler the filter had oil and oil cooler was warm is this a good sign or no my guess yes meaning that there is oil pressure and that the problem is maybe electrical.

 

The sending units on these cars fail at a horrendous rate. I would bet it is simply the sending unit.

 

If you didn't have oil pressure, the engine would eat itself within about 30 seconds. So it's not a pressure issue.

Check the sender. Clean the electrical contact as they tend to accumulate junk over time. The FSM contains exact instructions on how to test both the gauge and sender. You can do a very quick and dirty test on the gauge by briefly touching the wire to ground through a low value resistor. Have someone observe the gauge. It should jump when touched. If that works, then the sender is the issue.

 

ill go try that out.... i dont want to lose my rotary to a simple oil pressure problem.. thank you guys