My oil pressure seems to be low most of the time. I thought that this was relatively normal, but I expect it to increase more then it does when I get on the accelerator. Also, today on the way to work I noticed it abruptly jump up from it's usual low point to ~ 30 psi when I was just cruising at 3k rpms, it stayed up for a min, and then dropped back down as quickly as it had arrisen.

Is this normal?
What should the oil pressure be cruising at 80mph, 3k rpm, on the highway?
What should it be when you are at wot?
Is my oil pressure sensor flaking out?

Thanks.

 

On my '94 touring 76K miles using 10w30 dino juice(as opposed to synthetic), I initially see 60 when I turn the car on cold, but when it is warm, 30 is my normal while cruising, down to 15 when sitting at lights. Have no idea if this is normal, and glad you asked about this, as I've been wondering too. What's "normal"??

 

Cold startup can see as much as 120 psi. 3K rpm is typically 60 psi. Idle should be 30 psi.

The sender for your gauge is under the oil filter. It's a big canister poking out horizontally with one wire hooked to it via spade connector. First try pulling the wire and scraping the male end on the sender itself to make a better connection. If that doesn't help, pull the sender and "clean" it, using carb cleaner, a brush, and patience. If that STILL doesn't work, get a new sender. These things are known to fail internally, even after a fairly short period of time.

 

Yeah those senders go bad way too often. I am on my 3rd one in 3.5 year.. what a pain.

 

The numbers Spurvo posted are correct. You should get 30 psi at idle, 60 psi by 3000 rpm, and over 100 psi at high rpm and throttle.

The stock sender frequently goes bad or gets dirty. Clean it with a wire brush or replace it.

 

My '95 Mazda manual says a min pressure of 50psi at 3000 rpm on a warm engine. An old timers rule on safe oil "P" on rotary engines is 10 psi min for each 1000 rpm.

 

Replace that sensor. If you actually had low oil pressure you would be being towed by now.

 

thanks a lot for the input guys. I'm going to clean it up and see if anything changes. How much is a new one? Maybe it's not worth the effort of cleaning it. I have 108k miles now on the original engine, so I guess it's getting oil somehow. Thanks again.

 

I don't think it is worth the effort to clean the unit, it might work for a little while then it will do the same thing again(I got a hold of a used sending unit cleaned it, put it in and worked for like a week).
So best to get a new one.

 

I agree w/ Sinful7 (and others), replace the sender unit, there are many other threads that say the same thing. I had the same problem: oil pressure was fine when the revs were up, but at idle the pressure was very low or sometimes zero on the gauge, it seemed to be worse on hot days. I cleaned the connection on the oil pressure sender unit and it helped a little, temporarily. Finally put in a new OEM sender unit and the oil pressure reading has been normal - very comforting.
Bought my oil pressure sender from Mazdaformance (http://www.mazdaformance.com) for $71 - p.n. N3A1-14-820.
Late post, but just contributing my experience.