EVERYTHING YOU NEED TO KNOW ABOUT FUEL TRANSFER PUMPS AND FUEL PRESSURE

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We encouraged our sister company (the folks at the Turbo Diesel Register) to write about this subject. And write they did. It was a 14 page article that was published in Issue 56 of the TDR. The article was written about trucks from ‘94-‘07, and it covered everything from the correct fuel pressure; the importance of fuel pressure; how to remove and install a fuel transfer pump; and replacement options. With limited space, here is the summary. You can download a complete article from the Turbo Diesel Register Buyer's Guide at the link provided at the top of this page.

‘94-‘98, 12-Valve 5.9-Liter Engine
This engine has a robust, mechanical fuel transfer pump. Should the fuel transfer pump fail, it will not harm the expensive Bosch P7100 fuel injection pump. Replacement fuel transfer pumps can be purchased at Cummins or auto parts stores. The need to monitor the fuel pressure from the transfer pump to the fuel injection pump is minimal – no gauge needed.

‘98.5-‘02, 24-Valve 5.9-Liter Engine
This engine has a fuel transfer pump that is electrical. It is located on the engine next to the fuel filter. At best, its life span is marginal. Should this electrical fuel transfer pump fail, the lack of cool fuel to the expensive Bosch VP44 fuel injection pump WILL CAUSE THE VP44 TO FAIL. Replacement OEM-design fuel transfer pumps can be purchased at Dodge, Cummins, or aftermarket locations. WE WILL NOT sell this pump to a customer. Again, it is a marginal design.

Geno’s Garage does offer the FASS Direct Replacement Pump (DDRP) for these trucks as well as complete FASS high performance pumps and pump/filter combinations.

The need to monitor the fuel pressure from the fuel transfer pump to the Bosch VP44 injection pump is CRITICAL. You should do this with a gauge. We suggest that you not use a pressure light. The light illuminates when the problem has gone too far. With the gauge you can watch fuel pressure trends. Gauges range from $99 (Westach, electronic) to $130 (ISSPRO mechanical) to $225 (Auto Meter, electronic).

Regardless of your gauge choice, you have to tap into the fuel system. On ‘98.5-’99 trucks you can remove a 1/8 NPT fitting on top of the fuel filter assembly and attach fuel hose or pressure sending unit on top of the assembly. On ‘00-‘02 trucks, the filter design is different. So, we offer a Universal Fit Fuel Pressure Line (Vulcan-FH) that has a female adapter that screws directly into the Schrader valve test port that is located at the Bosch VP44 fuel pump. We offer several other ways to access fuel pressure for ‘98.5-‘02 trucks (banjo bolts, filter caps). We also offer several fuel pressure gauges that you can use to test the truck’s fuel system.

‘03-‘04.5, HPCR 5.9-Liter Engine
This engine has a fuel transfer pump that is electrical. Its life span is 80,000 to 120,000 miles. Should this electrical fuel transfer pump fail, it will not harm the expensive HPCR Bosch CP3 fuel injection pump. The Dodge and Cummins parts networks do not sell a replacement pump for these year model trucks. Instead they sell a kit ($350-$400) that changes the fuel pump’s location to an in-tank design. Labor for this conversion can easily run another $400. The in-tank design was adopted on ‘05 to current model year trucks. Geno’s Garage does offer a replacement fuel transfer pump for the ‘03-’04 trucks. It is part number PUMP-FPD4089602 for $179.00. We also offer FASS high-performance pump/filter combinations. The need to monitor the fuel pressure from the fuel transfer pump is minimal – no gauge is needed.

‘05-‘11, HPCR 5.9-Liter and 6.7-liter Engine
This engine has a fuel transfer pump that is electrical. It is located in the fuel tank. Although the test-of-time is not yet complete, it appears to be a solid design.