Hello!

First off, I'll say I've searched high & low for an answer with no luck.

My oil pressure gauge does not work in my 98 Cherokee 4.0. I've tried 3 different sending units from Autozone and now I have a Napa brand one in there with no luck. The Jeep does have the actual gauge, not the idiot light. The engine was swapped into this Jeep by me, and had great oil pressure. The original engine also did not give an oil pressure reading.

I've done the actuator test and the gauge does move as it should. Also, connected a meter to the senders harness plug. On the power side I get a reading of 5.22V(Green/Yellow stripe). The other wire is I'm assuming Brown/White stripe. Also, checked the gauge harness behind the cluster and got a reading of 12v.(LT. Blue)

I then checked the ECM's harness connectors with those two wires(LT. Blue & Green/Yellow stripe) and got the same readings.

I also tried checking the ground by switching the meter to OHMS and it gave me a fluctuating reading(1 pin connected to harness, 1 pin connected to body ground)

Anyone?

The port were the sender screws in may be plugged. Mine was when I switched from the idiot light to the gauge. Remove the sender and crank over the engine a few turns. DON'T LET IT START! Oil pressure should blow the plug out. Not unusual to get teflon tape plugging the hole.

Or just clean out the recess, put a gauge on it to make sure you actually DO have oil pressure and plug the new sending unit in there.......Now 3 weeks down the road, how did this go?

An after market gage would be a quick fix. Or just forget it. If you loose pressure the engine will "talk"" to you.

In that case you might as well refrain from all maintenance...