HMartin

Hi all, after recieving a new injection pump and intank lift pump I am not satisfied with the bogus fuel pressure. How does one go about eliminating the intank pump setup? Do I need to get a sending unit for the fuel tank like I had when the lift pump was on the block or what? I have a walbro that I am ready to install?

HMartin

Back to the top.

Blast Chamber

I don't have a 2nd gen truck or an in-tank pump, but I'll take a stab at answering your question. My understanding about the dealer-installed in-tank pump is that they run a wire harness from the original lift pump power plug back to the in-tank pump. You should be able to disconnect this plug-in and substitute a power harness with relay for the Walbro. You can either buy a generic harness with relay from an online auto parts store and add the Cummins harness for the fuel pump plug, or buy the FASS-II harness like I did (FASS part # WH-1002, cost about $45).

If the dealer replaced your stock fuel pickup with the in-tank pump assembly, you may have to install a new fuel pickup tube in the tank. Some guys have just used black-iron pipe and fittings to fabricate one that ends about 3/4" above the bottom of the tank. I'm not sure about what you mean in your question about the sending unit. If you mean for the sender for the fuel gauge, you should be able to continue using the one you have now.

Hopefully someone with an in-tank setup can chime in and answer your questions better than I did.

HMartin

That is the answer I was wanting to hear. Basically I can render the pump dead and put a siphon tube with a fitting in it to attach whatever fuel line I use to hook into the Walbro. I guess the next thing is do I need to hook up a seperate power line to the existing fuel gauge sending unit in the tank. [ ] Help me out here, I want to make sure my gauge still works. The thing that sucks is that I just priced the original sending unit assembly without the updated intank lift pump at the dealer and they quoted me $400.00 . So you all can see why I am trying to make what I got work without buying parts I have already paid for to begin with, thanks.

Blast Chamber

I'm guessing the original wiring is still there to plug back in to the original style sending unit? If so, I'd try some local salvage yards to see if they will sell you the original-style sending unit assembly from a wrecked truck.

Then sell your new sending unit/lift pump combo on eBay and make back some $$$$. I'll bet someone else with an in-tank pump will buy it just to carry as a spare during long trips. Seems they wind up backordered on occasion.

HMartin

Just put out an APB to the local salvage yard, we will see what they find. I'm still wondering if you can gut the fuel pump from the assembly and leave the fuel sending unit? I have a feeling when everones warranty runs out these things will be a pain to come by cheap. Just think $600.00 lift pump, $2000.00 injection pump, lord knows how much labor.

HMartin

Just wondering how are the 3rd Gen guys getting around this whenever the install a FASS or Walbro? I know nobody wants a truck without a nonfunctioning fuel gauge.

Blast Chamber

I believe that the guys with the '05 in-tank / Walbro conversions are just pulling their OEM fuel pump relay to disable the in-tank pump. They then run the Walbro off the dedicated relay that I mentioned in my original post. Sounds like the fuel sender must run off a separate fuse somewhere.

yarddog

I begged the dealer to give me the old in tank assembly when they replaced mine with the in tank under warranty. They said it had to go back to DC for "failure analysis". I thought if you haven't figured out why an engine block mounted lift pump has killed VP's in 50,000 trucks over a 4 year period, it's amazing your still in business.

Good luck with your conversion and please post any info you find on that in tank assembly. pics would be great.

slim51015

If the intank pump is anything like the gasssers, You could remove the unit, disconnect the pump from the unit, extend the pickup tube, and replace the unit.
It sucks you have to buy the whole module(on gassers) just because the pump is bad.

HMartin

Hey all, check the members photo gallery under member 2500CTD, he has some awesome pictures of an intank pump unit. If I didn't have to go in so early this week I be disecting this stupid thing. The plastic hoses are really cheezy looking, so much for durability!

2500CTD

Oh just incase, that metal "thingy" is what replaces the old lift pump. It bolts in place and the fuel lines bolt on to either side of it. One website that sells Walbros, listed those clear lines as supply lines to hook up the pump. they look cheesy, but work well. My main plan was to take the intank apart, (when I can afford to have the truck inop) and see if one of those intank walbros could be made to work. I went with the intank, cause my LP was dying and my sending unit was way off. I would run out of fuel at a little over 1/4 tank I'm hoping in the next 2 weeks or so, I will be able to drop the tank again and take a real close look at it. I installed my intank my self. As far as the wiring, IIRC It has a plug that plugs into the stock lift pump harness, has its own relay, has a power wire to the battery, and you just have to insert one wire into the connector behind the left front tire. So I believe you could just "reroute" the power wires coming from the intank's relay and use it to power a different external pump.

Here is where that clear hose is listed.