Archived Is My Fuel Pump Toast?

[Blue Thunder]

On the way to a friends house today, my truck started cutting out, and surging, followed by a lack of power. I made it there and shut it off. Later, when I tried to fire it up, it didn't want to start. Checked fail code, and it was the familiar 'P1693'. After turning it over several times, it finally started, but only ran for 30 sec. before it died again.



Please help. It feels to me like it is the fuel pump. Could it be any of the fueling devices? I just changed the fuel filter about 5k miles ago. I have another one on the shelf, so that is where I'm going to start.



What are the common signs of a pump failure??

 

[jwilliams3]

How is your fuel pressure from your lift pump?

 

[CRumsey]

Possible fuel pump failure

Blue Thunder



I had an experience similar to yours. It turned out to be a plugged fuel filter. Actually it was a bad batch of fuel as I went through three filters. I had to keep changing them every 50 to 100 miles before the problem cleared up.



Good Luck finding the problem, Carl

 

[Blue Thunder]

Sorry, no idea on fuel pressure.



I guess there are no tell-tail signs of a bad pump?

 

[B.G. Smith]

Fuel pump

You can determine if the pump is working. Have someone cycle the ign. switch to start and leave on, the pump will run for about 20 or so seconds. While it is running, open the drain valve on the fuel filter, you should get a good surge of fuel if pump is pumping. If the fuel flow is strong from the drain with the pump running, close the drain valve. Now loosen the banjo fitting on the side of the injection pump, have someone cycle the switch again, if you get fuel here, then it is getting through the filter and should run, might have to bleed a few injectors. If no fuel or just a little stream at filter, then pump is not working. If you have good flow at filter and no fuel at the inj. pump fitting, then the filter is plugged. Good luck. bg

 

[rkressg]

If you have a failed VP44, you should have more than just p1693. Usually the codes 1688 and 1689 are associated with a failed vp44, trust me, I know :{ .



When my VP44 failed, it would run up to 1600 rpm and defuel when in gear. I had DTC p1689, communicaiton error between ECM and injector pump. If I just freeweeled the engine, not in gear, flooring it would only produce 2600rpm and it would defuel hard to an idle and return back to speed in an infinate cycle.



Change you fuel filter and check if you have fuel pressure at the pump. P1693 just means there is a DTC in the PCU or a communication error between the ECU and the PCU, it means nothing.



If the truck will not restart after changing the filter, chances are it is a weak or non-functioning lift pump. Easy and cheep to change, buy it from a cummins dealer $150 or from D/C $225. No matter where you buy it, it comes in a Cummins box with a Cummins part number on the side.

If the pump ran dry, I hope the pump is not toast, due to it being fuel lubricated and fuel cooled.



If you have any questions, please feel free to ask.

P. S. if you have to change the pump, with the right tools and knowledge, it will take between 1. 5 to 2 hrs to change.

All you need is spring hose clamp pliers, 10mm and 13mm sockets, metric combo wrench set, 7/16 deepwell socket, special barring tool, small t-bar puller with 8*1. 24mm bolts, t45 torx, brakekeen, and wrags.

These pumps are easy to change compared to the p7100 and p4100, on the VP44, there is only one timing mark to line up