How can you tell when a 5.9 Cummins injector pump replacement is imminent? Some symptoms of 5.9 Cummins injector pump problems include lack of power, not starting, or hard starting. Bad injectors can also cause a knock in the engine.
There are two fuel pumps on the 5.9 Cummins. One is a lift pump that lifts fuel from the fuel tank. The fuel is siphoned to the main 5.9 Cummins injection pump, which then sprays it into the engine. In order to check the performance of fuel system parts, you’ll need a scanner.
You might not initially realize that the lift pump is broken. The Cummins 5.9 injection pump will continue drawing fuel out from the lift pump. However, since the lift pump no longer has enough force to do its job, it will eventually wear down the injector pump. The injector pump can’t handle the loss of pressure forever, which means you will eventually start noticing a lack of power in the engine. At some point, the engine may also be hard to start or not start at all.
The fuel injectors on the Cummins 5.9 engine should last between 120,000 and 150,000 miles depending on the fuel quality and regular filter maintenance. These fuel injectors fail due to mechanical wear and not dirt, so there’s generally no point in trying to clean them if they show signs of failure. Like many long-lasting diesel parts, replacing fuel injectors can be a pretty expensive job.
In order to diagnose whether your injector pump is failing, you will need a scan tool. Do not attempt to find leaks manually as the fuel system contains pressurized fuel up to 25,000 PSI. This amount of pressure can slice into your skin and cause fuel to enter your bloodstream, which could result in death.
Start by recording and repairing any active DTC as they might be related to the problem. Secondly, make sure that you have clean fuel and good supply pressure.
If your engine doesn’t start or is hard to start, it could be due to low or no fuel supply to the high-pressure injection pump. Check the rail pressure and make sure you have at least 4,000 PSI when cranking. If it’s less than that, it could be due to bad injectors.
If you crank the engine for 10 seconds and don’t see any smoke coming from the tailpipe, it means that the cylinders are not receiving any fuel. Most cranking and starting issues are caused by low rail pressure. Injector wear can also cause slow deceleration when driving and blue-white smoke when cold at idle.
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