01 4.0L 116k rounds. Runs/starts good. Great oil pressure, radiator doesn’t get hot. Do have a small phantom coolant loss. Going for a pressure test this week. However, My crankcase oil smells like gasoline. Thoughts?

 

How many miles on the oil?
How's gas mileage?

 

test for how fuel system hold pressure after shut off, if pressure rapidly drops, it is leak. if injector is leaky that may cause this symptom. if pressure holds, then i inector is not leaky.
a failed spark can also cause this too. but you got one of them wizbang high techie late model 2001 XJs, that techie stuff will show a code usually when you have an ignition miss.

 

1500 miles on the oil. MPG is about 15-18 normal in town driving with some freeway speeds. MPG goes down with trail driving through washes and mountains nearby here in AZ.

 

Threw a P0303 code a few weeks back, misfire cylinder 3. Attributed that to driving through a creek getting a splash over the hood and parking on an incline for a bit. Check engine light came on when I restarted. Pulled spark plugs on the front 3 cylinders and they looked great. Couldn’t get the back 3 as I couldn’t get the coil rail unplugged and didn’t want to muck up the electrical connector.
How do I check longevity of the fuel pressure ?

 

Get a fuel pressure gage. I think some of the big auto part store chains offer them as a free loaner tool.

Hook gage to the port on the fuel rail, (that port resembles a tire valve stem, with a pin that sticks out. there should be a metal valve stem cap over the valve, remove that cap to be able to screw the gage onto the valve stem.) Then fire up the fuel pump to read pressure, then off the pump and note how long pressure holds. I believe the specifications are in the factory service manual. I got a different year xj, with a Renix system, so my manual may give wrong value for your jeep.

Good luck, even under pressure!

 

Grabbed a pressure tester from AutoZone this evening. Going to test it with a cup of coffee first thing tomorrow!

 

Hmmm. High pressure coffee.....

 

Fuel rail pressure test results:
Fuel pump charged the rail to 48psi
After 5 minutes 45.5 psi
After 10 minutes 45 psi
After 15 minutes 44 psi

My interruption is nothing wrong with fuel pump check ball, nothing wrong with pressure regulator and a 4psi drop over 15 mins SORTA eliminates a leaky injector. Going for a coolant pressure test tomorrow to check on phantom coolant loss. Going to change oil/filter with new 30 weight oil and see what happens the next 500 miles.