Archived Diagnosis if a Lift Pump

[dclassens]

Had an 01 CTD QC 4x4 Dodge with an automatic trans come into the shop I work at with dead pedal like symptoms. Another issue was at high rpm in neutral it had lots of white/blue smoke. Used our fuel pressure gauge to test fuel pressure. While at 2500 rpm, the truck had 4 psi at the fuel tap on the injection pump.

Here are my questions...

What is the best way to test for a bad LP?

Where is the LP located on the truck?

What do I do from here to get best diagnosis?

Is there any step by step directions to fixing the LP?

Am I in the ball park.

Thanks a million!!!

Dave

 

[JKinney]

Did you turn the key on and off three times to check for codes? Sounds like the injection pump is going.



the fuel pump is on the left side below behind the fuel filter. Bump the starter but dont start leave key on and jump out you will hear the pump running. 4 psi is not all that good, but the filter could be plugged, which would lower the preasure. dismount the fuel filter but leave the hoses attached and you can get the pump out if need be.

 

[Gary - K7GLD]

The Lift Pump is mounted on the engine on the rear driver side, just behind and below the fuel filter.



This thread will illustrate and describe the internals of the Lift Pump:



http://turbodieselregister.com/forums/showthread.php?t=108275





Basically, if there is power right at the lift pump power connector, and the motor runs when power is applied, the vane pump rotor spins freely and pump vanes are free in their slots, and the filter screen is not clogged, the pump SHOULD be OK. A bench test, where actual fuel flow is verified, and done with a pressure guage to verify the pump WILL put out about 15 PSI, and do it for a reasonable test period, will clearly display whether the pump itself is good or bad.



If it proves to be good, but your problem persists, you have other fuel system issues - but let's do the easy and obvious first...