Buddies '04 quit

[Woodenhead]

I think the "this truck will run sans lift pump" rumor is the result of a bit of misunderstanding precipitated by the Duramax. The Duramax uses a very similar injection pump to the CR Cummins (in fact, it might be identical), but does not have a lift pump. Many people (quite understandably) assume, then, that what's good for the DMax is good for the Cummins. The reason that's not true is that on the Cummins, if the LP fails it becomes a major road block: fuel simply cannot flow past it (at least not in enough volume to keep the engine running).



I've often wondered whether the Cummins could be run without a lift pump if it were removed and replaced by a nice -6 or -8 AN line running from the in-tank pickup, directly to the filter, then on to the CP-3. Of course, a hand pump would need to be included to facilitate priming after a filter change (which is precisely what the arrangement on the DMax is).



-Ryan

With what little I know I'd say even if it did run without the transfer pump you'd run the risk of premature failure of the high pressure pump. I think this is the case with the 24V engines, first the lift pump starts to go then the hp pump gets starved for fuel and ends up failing next.



Just my $0. 02

 

[rbattelle]

With what little I know I'd say even if it did run without the transfer pump you'd run the risk of premature failure of the high pressure pump. I think this is the case with the 24V engines, first the lift pump starts to go then the hp pump gets starved for fuel and ends up failing next.

But the CP-3 has an internal "lift pump", of sorts. I don't think the VP-44 has such a device.



-Ryan

 

[Woodenhead]

Cool, I didn't know that (obviously). Maybe I'll have to hang around the 3G forum for a while and try and learn a little about the new trucks.



Like I said, with what little I know .



Mike

 

[steved]

As far as I can tell, you have three options really (to keep the system similar to what it came with... )... have a spare external LP ($307), have the newer intank LP installed (bad idea and $1000), or go aftermarket with either a fuel system like a FASS ($500), RASP (around $1300 plumbed), AirDog ($750), or a homebuilt one (Probably less than $500). The homebuilt one is probably then next best thing to the spare pump because you can choose the filters and the pump that are easiest for you to get near you... but this also requires a bit of research too.



IMHO, DC built our trucks with a LP... if it didn't need a LP, why would they have put one on??? Our Dodge has a Cummins, not a Duramax... GM engineers did not build our trucks, they built the Duramax for what it needed and our Dodge most likely needs a LP whether it is the fact it only acts as a priming system for the filter or it is needed to overcome all the restrictions in the fuel system.



steved

 

[RVTRKN]

Is it a 04 or a 04.5 C600

There is a difference from these trucks. The 04 would have the same set up as the 03. The 04. 5 as mine is, has a difference in engine components. Could it be possible?

 

[steved]

My 04. 5 has a fuel filter mounted pump yet... it is a 600CTD. The intank really didn't seem to take effect until sometime in 05... all the 06s are in the tank from what I have gathered. The fuel supply system on my 04. 5 is the same as his 03.



steved

 

[Gary - K7GLD]

But the CP-3 has an internal "lift pump", of sorts. I don't think the VP-44 has such a device.



-Ryan

In fact, the VP-44 *DOES* have a mechanical internal LP, very similar in design to the EXTERNAL LP - but mechanically driven...



That's primarily what has been keeping VP equipped trucks in motion long after the external LP has failed...

 

[RVTRKN]

well I guess that will be another research item for me. I lost a fuel tank pump in my old 94 360 gasser in the middle of the desert, that was no fun with no warranty at 96K

 

[rbattelle]

In fact, the VP-44 *DOES* have a mechanical internal LP, very similar in design to the EXTERNAL LP - but mechanically driven...



That's primarily what has been keeping VP equipped trucks in motion long after the external LP has failed...

I stand corrected... I didn't know that.



-Ryan

 

[TTubb]

The pump costs $307 from Cummins and takes two weeks to get (at least that is what the Harrisburg distributor told me).



The pump looked easy enough to replace... looked like 4 allen head screws, a wiring plug, and a hose lamp... might be hard to get at, but didn't look that bad. I was looking at it when I installed my FASS this weekend .



steved

I have a 2004. 5 also. Do you happen to know the part number from Cummins for the filter mounted lift pump you describe? Thanks

 

[kblranch]

Rbattelle If you are really interested in selling your lift pump pm me.

 

[rbattelle]

Rbattelle If you are really interested in selling your lift pump pm me.

Nah, probably not. I'm keeping it in case I decide to try to reinstall it some day.



-Ryan

 

[steved]

I have a 2004. 5 also. Do you happen to know the part number from Cummins for the filter mounted lift pump you describe? Thanks

Since the pumps "vary" by engine build number, you will need to contact Cummins with the information from your engine data plate... I believe these are located on the valve cover now... give them those numbers and ask for the fuel transfer pump or lift pump... they will get you the right part...



steved