5.9 Cummins Engine Injector Pump Problems

by Amy Rodriguez

Diesel fuel powers a 5.9-L Cummins engine through the use of a fuel injector pump. Many vehicle malfunctions are symptoms of a bad pump, which can cause poor engine performance.


The 5.9-L Cummins engine was used in full-size Dodge trucks starting in 1984. Initially, the injector pumps installed in the Cummins engine were mechanical. These mechanical pumps were later replaced by computer-controlled pumps, which offered more efficient fuel consumption and higher power output.


A problematic injector pump may affect the vehicle's idling, power performance and ignition features. Blockage due to fuel contamination is a common cause of a failed injector pump. The pump cannot move fuel through its assembly if the fuel contains a significant volume of debris.


Many fuel-system part failures mimic the problems encountered with a faulty injector pump. Before replacing an injector pump, check for a clogged fuel filter and verify that air has not infiltrated the fuel lines.

About the Author

Writing professionally since 2010, Amy Rodriguez cultivates successful cacti, succulents, bulbs, carnivorous plants and orchids at home. With an electronics degree and more than 10 years of experience, she applies her love of gadgets to the gardening world as she continues her education through college classes and gardening activities.

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