Am sure this has been answered somewhere along the way but I just can't find it. I have a 98 with 4.0L. My issue is that I have gas in the oil.

I have checked for pressure on the fuel rail after the jeep sat over night. The pressure was seemed fine. My thinking was that I had a stuck injector leaking down after shut down.

I have not noticed the fuel pump running after shut down causing the cylinders to fill.

I did read somewhere that it could be the fuel pressure regulator on the fuel pump. I have bought a new pump with regulator and will install that shortly.

I will also remove and clean the O2 sensors to remove the carbon build up.

I did have a fuse blown that affected the evap system and that was replaced.

Any other ideas or suggestions that may help me out here?

 

Running a 195° thermostat? a little gas in the oil is normal. If it's enough to change the level on the dipstick that's something else.

 

Yea when I did my oil change I took 8.5 quarts out.

 

Leaking injector, likely.

Any rough running symptoms?

 

Runs smooth, just gas in oil which creates a smoke field. Checked the fuel pressure and it is not loosing any.

 

Why are you sure it's gas? Have you checked your coolant lately?

 

Yes it's definitely gas.

 

What's a "smoke field"?

 

Raw gas and carbon out the tail pipe. Excess gas burning off.

 

Black smoke?
Can you scan live data to check the output from the CTS? If not you can also test it by measuring the resistance @ ambient temperature.

 

I have a scan tool and can see the live CO's just haven't had time to check it at this point.

 

Over 1/2 a gallon! Wow. The evap system on my 90 is sort of Passive". Just a vent from the charcoal can to the air cleaner.

Do you ever notice pressure removing the gas cap? Do you top up the tank on fill-up? I'm suspicious of the evac system. 2-1/2 quarts seems like allot from an injector. Sometime when it's smoking maybe pull the line off the can and see if it's wet inside?

I don't mean to distract from checking the CTS.

 

No pressure when removing gas cap. I purposely don't over fill because the last guy that had it didn't seat the O-ring properly on the fuel pump so it leaks if I fill it up.

I know when I bought it he had just changed the charcoal filter and all kinds of sensors. My guess is that he was chasing the same issue. He even put in a new O2 sensor.

I did find a blown fuse which was giving me emissions codes. Once I replaced the fuse it cleared several codes and ran better.

The timing has been checked and is dead on. At this point I am gonna change the fuel pump with new regulator and go from there. But, I will also clean the O2 sensor, plugs and recheck all the vacuum lines.

 

Over my head, A Caveman might disconnect the Evap system from the engine completely and see if there is any change. (just to test). (pretty easy I'd think) I suppose a guy should consider anything disconnected from the Evap would be a fire hazard, should be routed away. If you do enough at once we won't know what it was!

Fixing the known gas leak is good. CCKen made a really nifty hatch in his rear compartment to access his pump/regulator, and stuff. Has excellent photos.

 

Lol, yea I am only doing one step at a time. I want a definite answer on the issue my self. I just have to make the time to start with the whole process.

I will definitely look into making an access through the floor for future issues.