4-108 Oil Pressure Drop After Oil Change.

[phorvati]

Just an update, it turns out it was the gauge itself. I mounted mechanical oil pressure gauge at one of the 1/8" NPTF ports on the side of the block just below Injection pump. I had 55 psi cold, 40 psi warmed up. I guess oil change didn't cause anything. I was using my old oil gauge which stopped functioning. I replaced the sender for similar reasons in june.

[Ex-Calif]

Great news and congrats on the very happy ending!

[CSY Man]

Wow, lucky guy...

[phorvati]

One more twist. After putting a brand new oil pressure gauge I was still getting 5psi. So ended up getting another sender unit before I was able to measure correct pressures. So the sender I got in June now ohms out at >200Kohms. Its supposed to be 33ohm to 240ohm. How does a 2 month old sender do that? I am tempted to open it up and learn how Pressure gets converted to resistance and why this particular one went up few orders of magnitude in resistance.

[cburger]

It's usually something simple.

[Ex-Calif]

Originally Posted by phorvati

One more twist. After putting a brand new oil pressure gauge I was still getting 5psi. So ended up getting another sender unit before I was able to measure correct pressures. So the sender I got in June now ohms out at >200Kohms. Its supposed to be 33ohm to 240ohm. How does a 2 month old sender do that? I am tempted to open it up and learn how Pressure gets converted to resistance and why this particular one went up few orders of magnitude in resistance.

I had an ignition col failed right out of the box. Many parts ($$$) later I changed the $8 coil again. Most of the time we refuse to believe the new part is broken.

Here is more than most of us need to know about pressure sensing... The parts about hysteresis and repeatability are key... Maybe you got a weak/bad bourdon tube or bellows.

Fundamentals of Pressure Sensor Technology | Sensors