In order to have a reliable fuel injection system, the Cummins 5.9 comes from the factory with an OEM lift pump. This creates an immense amount of stress on the system and ultimately crushes injection pump reliability. Without a lift pump, the injection pump has to pull the fuel all the way from the gas tank to the fuel injectors. Lift pumps are responsible for pumping fuel from the gas tank to the injection pump. Injection pumps will pressurize fuel anywhere from 15,000 to 30,000 psi, which is extremely high.

The injection pump, also known as a high-pressure fuel pump, is responsible for pressurizing the fuel which gets sent to the injectors and into the cylinders. The Cummins 24v fuel injection system has three primary components: a lift pump, an injection pump, and injectors.

Accelerator Pedal Position Sensor Failure.

4 Most Common Cummins 24v 5.9L Engine Problems Despite the smaller powerplant, these engines are still capable of producing significant power, and tend to be more reliable than its competitors. Ford’s Powerstroke, and Chevy’s Duramax engine both use tradition V-shaped engines and have 8-cylinders instead of 6. The Cummins diesel engine is unique in the diesel truck world, as it is uses an inline design and only features 6 cylinders. Therefore, the Cummins ISB 5.9 is also commonly known as the 24v, or 24-valve. The engine continued in production until 2007 when it was retired for the 6.7L Cummins, primarily due to increased emissions regulations. The ISB 5.9 featured an inline-6 cylinder engine with multi-valve pushrods, and 4 valves per cylinder.

Here is our article on Cummins 5.9 12v engine problems. Midway through 1998, the 6BT was replaced with the ISB, which stands for “Interact System B”. Each cylinder had 2 valves, hence the name 12-valve. First generation versions were named the 6BT but also commonly referred to as the 12v, or 12-valve. The Cummins 5.9L “B-Series” diesel engine was produced from 1984 up until 2007.

07 5.9 cummins rear main seal