| VP44 is an electronic rotary distribution pump that produces high pressure fuel required for supplying fuel to diesel engines. The VP44 injection pump is found on Cummings diesel engines manufactured between 1998-2002. This pump is cooled by the fuel itself rather than by oil as was its predecessor the P7100 diesel injection pump. The VP44 also varies the timing of the injectors relative to the engine speed making sure that precise amounts of fuel are supplied to the engine for each injection cycle. The result is that the VP44 delivers the exact amount of fuel to the engine cylinders at the precise time. |
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Key Components of the VP44 pump:
- ECU or Electronic Control Unit, the brains of the VP44.
- The high pressure solenoid valve which is held closed to increase the fuel pressure, pressure is not increased by changing the rate in which the VP44 rotates.
- The angle-of rotation sensor.
- Radial-piston pump with pressure control.
- Injection advance device with valve.
- High pressure pump with distributor shaft and outlet valve.
There are several problems that can contribute to the VP44 having a shorter life span in many cases than the rest of the components on the Cummings engine.
Rotor Seizure Problems:
- In 2006 the EU put into effect low sulphur diesel fuel. The United States followed suite in 2007. The design for the VP44 diesel injection pump was designed to use the sulphur in the fuel as a lubricant. Therefore the low sulphur levels in modern diesel fuel can cause premature wearing of the pump.
- If the rotor in the VP44 was not “deburred” properly when manufactured then this will cause the rotor to be out of tolerance. Over time this can cause a grinding of the rotor and lead to eventual pump failure. Bosch took measures to correct this problem in its manufacturing process in 2000 so this type of failure is less likely after the year 2000.
- The lift pump that takes the fuel from the tank and supplies it to the VP44 diesel injection pump begins to fail causing the VP44 pump to be supplied with fuel below its tolerance level of 5 psi. This in turn causes wearing of the pump and eventually causes the piston in the pump to break the seals. Dodge later corrected this problem by placing the lift pump in the fuel tank. If your VP44 pump has failed in a Dodge model truck with a side mounted lift pump there is a high probability that the lift pump is supplying low fuel pressure and could destroy the new fuel pump.
Electrical Issues:
- The computer control unit for the VP44 is mounted on top of the unit. Over time the soldering joints of the computer control become crystallized and can lead to spotty or poor performance of the VP44 injector pump.
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