Just picked up a 2006 Jeep Liberty CRD a few days ago. It (230,000 Km) and the body is in great shape. It had a dead battery upon purchase and the seller swore up and down it needed a new lift pump in the tank. After dropping the fuel tank it was discovered that the factory lift pump in the tank wasnt even a lift pump. It's just a sending unit with two blue wires going to the float for the fuel gauge. This would mean I would have to either replace the wiring harness to the lift pump or just run power wires to the connector to power it. I plugged a scanner into the OBD2 port and its not giving me any codes. I have purchased a new lift pump which has the same plug as the harness except there are no power wires. Would I just run wires to the pcm and add a relay? What would be the easiest way to run power to the lift pump?

Check out the noob guide, the CRD didn't come with one but you can add it fairly easily.

viewtopic.php?f=5&t=54207

Lift Pump, one of the problems people have experienced is air in the fuel filter head. Some of these have been cured with the new replacement filter head, but some have not. Some people constantly experienced problems, and others like myself have never had an issue. The problem arises in that the tank does not have a electric pump in it, meaning the that injection pump must suck(as if through a very long straw) all the fuel from the tank, through the lines, and through the filter(which a dirty filter can also cause problems here). Since this system is under suction, and therefore a vacuum, instead of a little fuel leak that coats the filter with some grime, air gets sucked into and builds in the system until it replaces fuel being injected into your engine, and you loose power.

The solution to this problem is to install an electric lift pump in the system. Some have installed various aftermarket pumps at the tank, or before the filter head. But the most "stock" looking installation is to install a Dodge Ram Cummins Diesel in tank fuel pump assembly, and a gasoline KJ wiring harness. These parts are as much of a "bolt-on" modification as you can get. Simply drop the tank and install the new parts. The Cummins fuel pump assembly will sit right down in your tank like a factory install. For more information check out these links with lots of good info:
http://www.auerbach.ca/kj/lift_pump/

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Moderator,


As to your question:
FYI: These vehicles did not come from the factory with an intank fuel lift pump although they certainly should have.
From the factory, the CP3 injection pump is forced to suck the diesel fuel all the way from inside the fuel tank through the fuel filter and into the injection pump. A poor design indeed!
Vehicles without a lift pump installed are subject to have all kinds of air in fuel problems as reported by many owners on this forum and on the Jeep CRD FaceBook Group.
Many owners like myself have installed the Dodge Cummings Diesel Truck low pressure (12-15 psig) intank fuel pump. It is a direct drop in and only requires adding two additional wires from a plugin connector under the rear seat to the top of the fuel tank.
See this web page for more information and instructions on installing and wiring up an intank fuel pump.
http://www.auerbach.ca/kj/lift_pump/default.html

The vehicle came OEM from the factory with the software programming logic already installed in the ECM for a lift pump and has all the necessary wiring and a relay already installed up to the connector under the rear seat. Covered in the writeup.

Some owners opt to simply install a low pressure inline fuel pump while this will suffice, it is not ideal since if there is a leak anywhere on the suction side of the fuel pump, it will still suck air into the fuel system which can cause all kinds of running issues.
The beauty of the intank fuel pump is that it puts the entire fuel system under constant low pressure all the way from inside the fuel to the the CP3 injection pump.
Once an intank lift pump is installed and operational, if there is a leak anywhere on the fuel feed system, it will be self evident very quickly as diesel fuel will leak out rather than air being sucked into the fuel system.

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Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

Ok Ive installed the cross referenced fuel pump from the Dodge Ram Cummins. I re wired the harness, tested the fuel pump, it pumped out the remaining 5 gallons of fuel into a 5 gallon pail. I re installed the fuel tank, hooked everything back up and even went and got 10 gallons of new diesel from the pump to put into the tank. I purged air from the fuel line from that little bleeder on the side of the fuel filter head. The engine will crank and crank but still won’t start. I had my scanner hooked up to it with no codes coming up. Could the lines to the injectors also be air locked? Any other suggestions would be great. I’m beginning to think that it’s the Cp3 pump. I just want to know for sure before I spend that kind of money.