Hi, just an update as I have not had much time to actually work on the problem. I have done a lot of reading and thinking on the issue and over the weekend I ran the checks on the Fuel pressure Sensor, Fuel pressure solenoid (aka: POV)which are located in the fuel rail and the Fuel Quantity Solenoid (aka: MPROP?) located on the CP3 pump. I prefer to address the parts by the name given them in the Jeep manuals although there seems to be many names out there in the real world.
Anyway, I ran the checks cold, and then warmed up real good and all checks were within ranges specified. Interesting that the last step in P0093 check indicated that if everything checked yes, then replace the Fuel Quantity Solenoid (FQS) and if not the replace the ECM. I have not as yet resigned to do that as in one test procedure the manual says to replace the fuel pressure solenoid and if problem still exists to replace the fuel pressure sensor, and if problem still exists to replace the fqs (talk about using a shotgun)

However I am leaning strongly at the FQS as the symptoms fit the problems caused by a faulty FQS more so than with the FPS running a close second. The FQS seems to fail more because it is first in line to suffer problems related to water and other contaminates in the fuel system. I found the below comment by one tech on Justanswer as to what exactly happens when the FQS or MPROP valve starts to stick and why.
" Hi, You could have a sticking MPROP, they are very susceptible to scoring, this makes the MPROP unresponsive at first, because it requires more current to move it than the ECM tables deliver, eventually it may stick fast in a position, or it may live.
Your symptom is typical of a sticking MPROP, as the load comes off the engine, the ECM commands a reduced fuel flow (pressure) by closing down the MPROP to a predetermined position, however the sticking MPROP is too slow to respond, the ECM does not see the pressure drop quick enough and closes the MPROP even further, suddenly the MPROP moves and closes too far, you may get a stall or just a low pressure fault code. The Cummins (Bosch) CP3 pumps have replaceable MPROP's, I do not know about the pump fitted to your MAN engine, but you could try swapping from another pump (same part number) that has failed for a different reason, or try a Bosch dealer.
Not all MPROP's are the same, they are graded (same part number) for fuel flow, and different part numbers have different flow rates.
They are very easy to replace, just 3 Torx head capscrews.
Read more: MPROP VALVE - JustAnswer
http://www.justanswer.com/heavy-equipme ... z1wHoTyizQAfter reading this, I am thinking just the opposite would be true also, if when load increases and the valve sticks there would less fuel pressure than the ecm wants thus it would ask for more and not getting it would then stall or go into limp mode and register a low pressure code. I am still researching but at this point if I have to start replacing parts I would start with the FQS. So does anyone know what that part number is for the FQS, who makes it and where I can get one?
On another subject I went to napa today looking for info on Glow plugs. They could not find any for the 2.8 and called Bosch who indicated they no longer make the glow plugs for the 2.8 crd. Can anyone give me a recommendation as to what brand of glow plug would be best and the part number for it. I would prefer ones that are not ceramic.
Thanks all.
Mark
05 liberty Sport, custom filter head and lift pump