The 03-04.5 trucks with the lift pump on the engine this would not be to difficult to rig up,but the intank pumps on the 05+ would be a real pain.You would need to drop the tank and have a drawstraw installed and a few other things in advance of a pump failure.

 

I thought I read that one reason for the intank pump is that if it fails it does not leave you stranded because the CP3 can draw fuel through it but the external pump blocked the fuel when it fails leaving you dead on the road.

 

You are one cheap SOB. I think it would be justice if the next part you order on line, when you get it you find it was a used part. I mean the other guy just needed it for a few days!!!

 

I was about to make that statement myself, i thought duramaxs just used a cp3 and no lift pump.....???

 

X2. Kinda like the people who were buying lawnmowers from Home Depot and then returning them at the end of the season saying they weren't 'satisfied'. And we wonder why stores have to tighten up their return policies and make it more of a hassle to return an item for legit reasons.

 

they still dont run lift pumps.

no duramax has ever had an external fuel pump from the factory and they work just fine up to about 400rwhp. After that a lift pump helps.

 

Not to mention that once you run fuel through a carb or pump, most places will not take back.

 

It would depend on the design of the pump.
When my Weldon pump died it stalled the truck.
But I lost power to my walbro and the truck ran fine.

 

Ok well just so you guys know i wasnt refering to buying the pump and then taking it back to the store so before you guys jump your crappy judgement realize that words can be used variously. I was simply refering to returning it back to the Airdog since my suggestion was a different LP obviously you people are too smart for my SUGGESTION...last time i post on this site...

 

The OEM in-tank LP will pass fuel flow in failure mode.

It will not allow enough volume for max HP production (as Jason surmised, 400HP is as good a guess as any).

We typically leave the in-tank LP in place when retrofitting an aftermarket high-flow system, so it can function as a pre-installed spare. A toggle switch, indicator light and bypass valve make it easy to either use the OEM pump in the event of aftermarket failure, or as a way of "saving" the expensive pumps for competition use.

 

This is a pleasent surprise to read about this. I like the idea of the in tank LP failure not being a catasropic stuck on the road type of failure.

 

Well, it just so happens that last night my walbro quit when the family and I were leaving a theater. I drove the whole way home with 0 pressure showing on the low side gauge. I took it easy on the truck, but didn't notice any difference in the way it ran.

 

You'd have to put your foot in it to notice.

Can't necessarily go by a rail pressure gauge either, as no lift pump during much of the medium-range fueling doesn't register a significant difference of RP, but power & smoke are noticeably less.

Just goes to show that fuel flow quality is also important in the high-pressure supply side of a CR.

 

Interesting.. I wanted to remove the in-tank and put in a LP so that I can bypass it easily if it fails.. I know the in-tank was designed to bypass, but heard it rarely does...

I may just have to leave it there.

 

I don't profess to know anything about anything. But from what I've read on the various forums in regards to the topics in this thread is--

1. The D-max's CP3 is slightly different than the CP3 in our 5.9L, but more closely resemble the CP3 in the 6.7L.
2. The in tank LP will allow fuel to be pulled through it, whether it has failed or not. This has been tested and confirmed.

Please correct me if I'm wrong on this!