Hello everyone, I have a quick question regarding a sudden oil pressure loss in my 2003 TJ 4.0. I have researched a number of threads reporting a common issue with the Oil Pressure Sending Unit. I replaced it (Yes with an OEM Part from the dealership). Nevertheless, the problem persists. The sudden drop does not occur at a specific time, in other words, the pressure drops suddenly while driving, while stopped, when accelerating, when coasting. The oil pressure drops, bells go off, red "check gauges" light illuminates and then within 1-2 seconds, normal oil pressure returns. Any insight into what my next step should be, would be appreciated. Thanks again!!
TJ Sudden Oil Pressure Drop
- Thread starter Lukefoster
- Start date
Elyse8743
TJ Enthusiast
Oil levels ok? I had this issue and after researching it on here, got a new Mopar OPS unit, same problem even after replacing. Checked the oil levels and I was low, added a quart and the issue went away instantly.
Check for chafes in the wiring for the oil pressure sending unit.
Couldn't hurt to check the harness that is routed around the back of the valve cover towards the drivers side; this harness is known to rub against the head stud wearing thru the wire loom and shorting to ground.
Check the ground harness near the oil filter and oil pressure sending unit to ensure it is clean and tight.
Couldn't hurt to check the harness that is routed around the back of the valve cover towards the drivers side; this harness is known to rub against the head stud wearing thru the wire loom and shorting to ground.
Check the ground harness near the oil filter and oil pressure sending unit to ensure it is clean and tight.
MrMark52
TJ Enthusiast
My ‘03 4.0l does the same thing on the rare occasion. I’ve looked in the harness that CharlesHS mentions but have not seen anything.
Usually happens when I start it, has not happened while driving. Kill it, restart and the problem is gone.
Since it hasn’t been the squeaky wheel lately the cause has yet to be determined.
Usually happens when I start it, has not happened while driving. Kill it, restart and the problem is gone.
Since it hasn’t been the squeaky wheel lately the cause has yet to be determined.
Thank you, I had the same thought that it may just be the new unit I installed is bad. Thanks again.
MrMark52
TJ Enthusiast
Before you go buying another sending unit, I would make sure the wiring connector “snapped” when you popped it back on. Also make sure the inside of the wire harness end is clean and not for some reason corroded.
I realize that things like sensors are functionally black magic in how they work, but I hear of far too many complaints about ”bad” new sensors that were replaced with good ones - when the real problem was the contacts of the connectors were dirty and made connection the second time that the connection was remade, or the connector wasn’t fully snapped into it’s (folded and) locked in position (a little airline humor there
).This particular sensor is nothing more than a resistor whose resistance changes as it gets hotter or cooler. No black magic to it, other than how it’s used electronically in its circuit before it’s signal gets to the microprocessor in the cars computer where the computer does what’s called “A(nalog) to D(igital) conversion”, if needed at all within the computers firmware.
Similar threads
