Hi guys, I have a 1993 xj and whenever it warms up, the oil pressure dips down to near 0 at idle. Once I accelerate is goes back to around 40. I read it could be the oil pressure sending unit but I replaced that and still have the problem. It also isn't passing smog so could the oil pressure problem have anything to do with that? Thanks, anything helps.

 

oil pressure won't affect smog. you need to verify pressure with a mechanical gauge, remove oil pressure sending unit and put a mech gauge place in its place.

 

Not sure on the oil pressure, but failed smog could be an O2 sensor, or a vacuum leak, or it just needs a tuneup, or a combination. Never hurts to check the fuel pressure.

 

Yep. I got a Bosch for $16 on sale. Took me all of ten minutes to:

1. Remove stock sending unit.
2. Connect Bosch.
3. Set Bosch gauge on cowl in front of windshield.
4. Get in.
5. Start engine.
6. Read Bosch.
7. Shut off engine.
8. Get out.
9. Remove Bosch.
10. Replace stock sending unit.

That confirmed that I had good oil pressure. No worries. Then I got a new sender, and all is well.