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Sorry for the delay, work has been busy.
I'm not going to guarantee this is the approved troubleshooting method, but it worked for me.
First thing I did was upgeade filterhead and install lift pump to ensure no air in fuel. Once I was. Positive there was no air in the system, I followed the following diagnostics, which was a mixture of info from many different sources
Following a suggestion from the guys at the cummins commonrail forums, I shot a little either into the intake and cranked it over. Doing this, the liberty started and ran fine. Under heavy load conditions, the jeep would defalt to limp mode, but it would still run.
Next step was to take off the fuel return rail and check for excessive retuen from one or several injectors. After removing the fuel rail, (keep it in one piece and be very gentle with the plastic fittings that clip into the top of the injector. If you break one, you get to buy the whole fuel rail for $45.00 - ask me how I know. Also, don't drop any of the clips, as they are dealer only for $50/ea, and not available locally...) I insterted a 5" long piece of clear vinyl tubing into the top of each of the injectors. I cranked for 10 seconds and looked at the levels in each tube. They were all at the same level, and about 1/4" up the tube. Which is normal. If one or more is significantly higher ( I read that it could be 3-4 inches of fuel after 10 second of cranking) then you have a failed injector preventing rail pressure buildup. This was not the case for me. Also, don't break the plastic fuel return junction (where all three fuel return lines join up) before heading to the tank, as it is dealer only and runs $97 and not available for a week. I built one out of brass fittings from home depot for about $20. Much sturdier.
Next, I reinstalled the fuel return rail, and pulled the line off of the pressure control valve at the rear of the fuel rail. I cranked for 10 seconds and had a significant amount of fuel drain out. While cranking, but not running, this valve should be held shut preventing fuel from flowing at all. In my case, the valve had failed, once replaced, the jeep started easily.
It is my understanding that if the PCV had been good, the only thing that could cause low pressure would be the CP3 pump. From my reading, the pump itself rarely fails, but the MPROP valve bolted to it fails regularly.
I was able to give the part number off the PCV to a local diesel shop and they had the part next day for $449. The dealer was a week out and $849.
I tested the components in this order as it was the best way I could figure out to determine with the highest degree of certainty which component had failed without buying needless expensive components.
Fyi, that PCV valve is a very complex item. It is a normally closed valve. It is held shut with a spring, but gets additional closing force from an electromagnet. The spring itself does not provide enough force to get the rail pressure above 5000psi. The ECM varies the current to the PCV, the higher the current, the more closing force, and the higher rail pressure. Somehow this works in balance with the ECM sending a signal to the MPROP valve which both maintain predetermined rail pressure.
Hope this helps someone.
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2005 Black Limited CRD, GDE ECO tune otherwise stock. 165K and hoping for 500K
Last edited by bigbillyboy on Sat Jan 29, 2011 12:15 pm, edited 1 time in total.
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I'm sure there will be more instances of "cranks but no fire" for us in the future.
Maybe papaindigo will search it out for you 