Rattaan

Since the last time I changed my oil pressure sender unit, I keep an eye on it a bit more often. I've tested the system pressure with a mechanical unit to compare with the FSM and it was right where it should be. The reason I'm asking though, is because the readings on the dash unit change more than just from an idle speed to a 3000rpm rate. I also remembered seeing something in the FSM about a lower reading when the bypass is active. What will cause the bypass to be active, how much will it cause the pressure to change, and are there other reasons that the pressure won't stay perfectly steady at a steady rpm? Sorry if this is a useless question, but my curiousity is getting the best of me.

RETed

oil temp
oil viscosity
oil thermo pellet in front eccentric shaft bolt
oil thermo pellet in oil cooler
oil filter
fuel dilution


-Ted

WAYNE88N/A

Don't forget about the actual animals that control the pressures in the first place- the regulators...And of course the various o-rings trying to keep all of these pressures from busting loose...

And Ted- you forgot "premix dilution" also, lol...

RETed

Oops, also forgot about the obvious one...
Engine RPM's


-Ted

Rattaan

I almost forgot that I posted this question. Thanks for the answers guys, I knew a few but wondered if there were more and what they would be. So I shouldn't worry when I'm cruising along at 3.5k and the pressure goes from 60 to like 50 and then later back up again, right? I did notice it tends to run a higher pressure after a few runs to redline and sustained high revs. Is this temp related?

Tristan Bull

I have a problem very similar to this. I noticed yesterday that my oil pressure gauge started doing some really wacky things. It moves around when I'm travelling at constant speed. I'll be doing 75mph on the highway and the gauge will drop down to say 30 or just above 0 and sit there for a bit and then go back up to about 50-60. I just rebuilt my engine, and it has about 150miles on it now. The oil pressure thing started yesterday. I pulled off tot he side of the road several times to check the engine on my way home. It didn't appear to be smoking, and there weren't any noticeable oil leaks or drips anywhere. I checked the oil when I got home and it looks fine, and the level is still full. For that amount of variance, I think I should surely see some indication of a drastic problem. I'm guessing(hoping) that either the gauge or sender unit is bad. Anybody have any ideas?

RETed

I think that is still within spec.
The stock oil pressure sensor is notorious for failing.
Double-check with an aftermarket gauge or a known good mechanical one to verify if the readings are proper.


No, this is engine RPM related.
Oil pressure goes down as the engine heats up, so on initial start-up, oil pressure will always be a tad higher.


-Ted

RETed

As I have said previously, the stock oil pressure sensor goes bad.
Verify with a known good oil pressure gauge first - it sounds your sensor has gone bad.


-Ted