Fleece Performance 04.5-07 GM Powerflo In-Tank Lift Pump
The Fleece PowerFlo FPE-34789 is an in-tank lift pump for the 2004.5-2007 Chevrolet Silverado and GMC Sierra 2500/3500 with the 6.6L LLY or LBZ Duramax, classic body style only. If your truck loses power on a long pull, dies after running near empty, or you are adding fuel and want the CP3 fed under pressure instead of pulling fuel from the tank, this is the drop-in way to do it. It replaces the factory sending unit assembly in the tank and adds a pump the truck never had from the factory.
These trucks came without a powered lift pump. The CP3 high-pressure pump has to draw its own fuel all the way from the tank, through the filter head, under suction. Suction makes air leaks and restriction worse, and a tired or clogged supply side starves the CP3 first. The PowerFlo puts two gerotor pumps inside the tank so fuel arrives at the filter and CP3 already pushed, at the 10-13 psi idle pressure Fleece lists for this unit. Fleece rates it to support up to 800 hp, including dual CP3 setups.
The pump sits in an active fill bucket, so it keeps its own pickup flooded. That is what lets it run down to a low tank without the quarter-tank starvation that frame-mounted pumps with a stock pickup often suffer. The supply and return ports are threaded for -8 O-ring fittings (3/4-16), so you can keep the factory lines or run your own lines and filters later.
A failing fuel level sender or a stuck fuel gauge also means the in-tank assembly is coming out anyway. Swapping to the PowerFlo at that point costs you only the price difference.
Start with the easy items: a fresh fuel filter, a check of the primer and filter head for air leaks, and a scan tool watching desired versus actual rail pressure under load. If rail pressure drops away at full throttle and the filter is new, supply is the likely limit. Rule out the high-pressure side too. A worn CP3 or a sticking metering valve such as the Exergy LLY inlet metering valve can look the same. If the Allison behind the engine is also flashing codes or going into limp mode, read our Allison 1000 limp mode guide so you can separate a transmission fault from a fuel supply problem before spending money on either.
Fleece lists FPE-34789 for these trucks:
It cross-references GM sender numbers 19331306, 19303427, 19152169, 19331307, 19303428 and 19206540. It is for single-tank pickups only. It will not fit S&B tanks, Titan tanks need a check against the Fleece fitment chart, and cab and chassis trucks must match their pump number first. The 2007.5-2010 new body LMM trucks use the separate FPE-34790, and 2001-2004 LB7 trucks have their own PowerFlo. If you are not sure which body style you have, send us the year and VIN before you order. See more Duramax and Allison parts on the Allison 1000 page.
Fleece estimates 2-3 hours. The tank has to come down: disconnect the batteries, remove the filler line and the supply and return lines at the fuel cooler, support the tank and pull the two 15 mm strap bolts. Clean the top of the tank before you open it, mark the sender orientation, and turn the retaining ring out with a punch. Clip the float arm on and check that it clears the wires and tubes through its full travel, or the fuel gauge will read wrong. Do not rotate the unit once it is in the tank.
The kit includes a relay harness. It runs to the battery and to a 10A switched ignition circuit through the included fuse tap. Never fit a larger fuse than supplied. Never run the pump dry, and make sure the fuel lines are clean before you start. Put in a new fuel filter when you are done. Builds that also add a bigger injection pump often pair this with the Exergy LBZ Sportsman CP3.
| Brand | Fleece Performance |
| Part number | FPE-34789 |
| Fits | Fleece Performance 04.5-07 GM Powerflo In-Tank Lift Pump |
| Type | Fuel Pump Hangers |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Only if it is the 2007 classic body style with the LLY or LBZ. The 2007.5 new body trucks with the LMM take FPE-34790 instead. Check the body style or send us the VIN and we will confirm.
No powered one. The CP3 pulls fuel from the tank under suction. The PowerFlo adds two in-tank gerotor pumps that push fuel to the filter and CP3, at 10-13 psi at idle per Fleece.
Yes. The sending unit comes out through the top of the tank, so the tank has to be lowered. Fleece estimates 2-3 hours with basic hand tools, a hammer and a punch.
It does not fit S&B tanks. Titan tanks vary by model, so check the Fleece Titan fitment chart. It is for single-tank pickups, not dual-tank setups.
Fleece validates PowerFlo pumps for up to 20 percent biodiesel (B20). Use a fresh fuel filter after the install either way.
Yes. It uses a float arm and level sender. Make sure the arm clears the wires and tubes through full travel before the unit goes in, or the gauge can read wrong.
