Oil Pressure Gauge Reads 0psi

[megu2ice]

I have a sunpro electrical oil pressure gauge hooked up that was previously working. Recently I've noticed that my gauge now only reads 0 psi during all conditions. I have the sender hooked up to an oil filter sandwich plate and all connections are tight. There's 12v between the power and ground terminals and 7v between the power and signal terminals.

I'm scared to drive the car like this not knowing if its a faulty sensor or I actually have very low oil pressure. The stock oil pressure switch is still connected and I'm pretty sure it still works yet the light never comes on.

This all started roughly after I hooked up the turbo oil feed line that's also connected to the sandwich plate. I'm pretty sure it still worked after the install but I'm not certain. Already checked for oil leaks and nothing. Oil has recently been changed. I'll remove the oil feed line and check for pressure this weekend if time permits.

In the meantime, any clue what might be going on?

[megu2ice]

Quick update

The gauge is now responding, less than 10 psi idle and around 25 psi under light acceleration. This still seams low but I guess its better than 0 right?

[nomansland92]

Ya that's pretty low, I believe I idle around 20-25 and 70ish around 3k, and I think the stock oil pressure light comes on around 7psi.
I know I originally got one of those eBay adapters and I noticed a ton of aluminium burrs In the threads so maybe a burr got stuck in the line?
Hope this helps

[95BMWIC]

When you turn the ignition switch on, the warning light on the instrument panel should light up - do not start the engine - when the engine is started the light should go out..

It sounds like you know how to use an ohmmeter - so just as a precaution I would test the oil pressure switch - to know that it still is functioning..

Remove the connector from the switch and connect an ohmmeter between the switch terminal and ground. With the engine off, there should be no continuity. If any faults are found, the switch is faulty and should be replaced.

Edit - Switch is located by the oil filter housing on a 325i

[megu2ice]

I never checked the plate for burrs, I'll remove the sender and check tomorrow as well as test the switch. Thanks guys.

Note - My oil warning light on the dash does work

[AndrewBird]

Maybe the turbo oil feed line is bleeding off pressure at the plate? I'd be curious to see what the gauge does with the oil line blocked off.

[megu2ice]

Stock oil pressure switch is working fine. Out of the blue the oil pressure gauge started showing regular pressure, 25psi at idle and 50psi under acceleration. That was without making any changes but now its back to the 0 psi nonsense.

[Jaxx_]

I believe I idle around 20-25 and 70ish around 3k

70psi at 3k? jesus.

Perhaps you might have higher oil pressure when the motor is cold, but 25psi at idle is ridiculous. You shouldn't be measuring oil pressure by engine load, but rather RPM. A good rule of thumb is 10psi per 1k RPM.

Knowing this, 10psi at idle is fine. You don't want too much oil pressure anyway. Think about a garden hose--you can have high pressure with low flow, or lower pressure with higher flow.

[megu2ice]

Makes sense. Can I use any regular mechanical pressure gauge hooked up to my sandwich plate to determine if my gauge is having electrical issues or the engine has no pressure?

[nomansland92]

Ya you can do that

[digger]

My gauge reads quite low at times but i don’t trust it much because the dash light (now 13psi instead of 7psi ) never comes on until the engine is at low rpm like 600rpm if its about to stall, the width of needle is like 10psi, im going to try find a gauge with better resolution.

[megu2ice]

Problem Solved!

I used some teflon tape to ensure the sending unit would seal properly. That being said, there must of been some overlap on the edge of the threads which eventually clogged the small inlet on the sending unit. Either way I removed the electrical gauge and replaced it with a mechanical one. The resolution is much better and oil pressure is back to reasonable values.

Thanks for all the help guys.