Need help, P0193 code, Liberty CRD
 

Hello,
Hope this isn't too long winded. Just trying to be thorough about the problem and everything I have done so far.

New to this forum, not new to diesels.
But this is a new problem that I have not been able to nail down.

2005 Jeep Liberty CRD 2.8L.
Developed rough stumbling acceleration.
Idles just fine but will occasionally stumble and die after reving the engine.
P0193 code.

Also, after driving like this for awhile, it will go into "limp mode" and throw a P0190 code.
While it is limp mode, the the stumbling acceleration stops, but overall acceleration is poor. Its drive-able like this but is a clear indication that something is seriously wrong.

I can use the TorquePro app to monitor rail pressure and other sensors while driving.
When it is stumbling with P0193 code, fuel rail pressure readings seem normal and go up and down with throttle.
But when limp mode and P0190 code sets in, fuel rail pressure maxes out at 25,600 psi and stays there. Does not come down at all.
I also discovered that TorquePro does NOT provide direct reading of fuel rail pressure. The sensed fuel rail pressure signal come from the rail pressure solenoid.
So actual rail pressure is unknown.

New fuel filter head and filter has been installed.
Lift pump has been installed.
Low pressure side of fuel system tests good. Great flow from tank through fuel filter with no air bubbles.
Did injector return flow test. All four look good.

Fuel Pressure Sensor was the first thing I replaced. Did not help.
Did resistance checks of both new and old pressure sensors, both tested good.
Rail Pressure Solenoid tested good.
Did continuity and voltage tests between sensor, solenoid, and ECM. All wiring tests good.

I'm now down to one of three things:
1. fuel quantity solenoid on CP3 (I've already tested the wiring between this solenoid and ECM and wiring is good)
2. the CP3 itself
3. the ECM

What do you think?
Am I headed down the right path?
I'd really like to know what the actual rail pressure is but cant find any kind of gauge that will work for that.

Thanks

Dave
Jacksonville FL