Off topic from Hot Rod's - 4 cly question

I have a problem with my 93 Australian built Capri with the Mazda engine that just started. When I start it up the oil pressure will read very high and stay high until the first time I stop and drop to idle ( after it’s warm). Then the pressure will drop very low or bottom out, then as soon as you come off idle and go back up to 1,500+ rpm the pressure will clime back to normal or low normal until the next stop the bottom out again. The oil level is fine and it’s not losing or burning oil. The oil and coolant is clean and normal and I pulled the oil pan and pickup and they were clean. The engine also runs and sounds like it’s new. I am thinking it’s the oil pump going south? Any other thoughts?

Thanks,

Charles

Set the oil pickup about 3/8" off the bottom of the pan. I would guess that the pickup is set very high and is being uncovered on stops.

Most engines have low pressure at idle. If it has any at all its probably not a problem. By the way, thats the main reason most makers went to idiot lights.

sounds more like a gauge/resistor problem. Do any of your other gauges go nuts? I had an 85 Mustang GT many years ago that the gas gauge and oil pressure gauge would go nuts in and it turned out to be a voltage drop problem. Had a resistor or what ever that dropped the voltage from twelve to 9 volts that went bad once in a while. Since Ford has owned Mazda for many years and they use a lot systems in common, this might be your problem. The voltage drop system wouldn't go bad until the vehicle was warmed up and the alternator was easing off letting the battery provide most of the power. Hate to see you tear apart a motor that doesn't need to be torn down.

get an aftermarket mechanical gauge . it could be your guage or the engine, I would eliminate the guage first and then if the oil pressure shows low at stops with the new guage, then you will know its the engine.

Thanks,

The pickup checked out OK. On the way into work today after it took the drop it would not come back up. I will get a different gauge and check it out as my voltage gauge is running on the high side.



Charles