How To Check Injector Pump On 5.9 Cummins 


The 5.9-liter Cummins engine burns diesel fuel using a fuel injector pump. Bad pumps can cause a variety of vehicle malfunctions, including poor engine performance. 


A 5.9 Cummins engine has two fuel pumps. A lift pump and a high-pressure pump, also known as a CP3 in this application. The lift pump is a device that removes fuel from the tank and supplies the CP3 at low pressure. The high-pressure injection pump pressurizes the fuel up to 25,000 psi in the common injector rail. A scanner is necessary to check the performance of fuel system components. 


Signs Of a Broken Lift Pump 


If you don't notice a problem right away, the lift pump may be malfunctioning. On the Cummins 5.9, fuel will continue to flow from the lift pump to the injection pump through the injection pump. The lift pump wears out the injector pump because of the decreased force it produces. The injector pump will be unable to cope with the loss of pressure. As you will begin to notice a reduction in engine performance. It is also possible that starting the engine will be difficult or impossible at some point. 


Does an injector last long? 


Fuel quality and filter changes will affect the life of Cummins 5.9 injectors. Cleaning these injectors generally fails due to mechanical deterioration. Injector replacement, like many other long-lasting diesel components, can be pricey. 


How To Check Injector Pump On 5.9 Cummins 


To diagnose a failing injector pump, you will need an injector pump scan tool.  It is possible to pressurize the fuel in the system to 25,000 pounds per square inch. You should not search manually for leaks. Fuel may enter your bloodstream as a result of this amount of pressure, resulting in death. 


It is important to check and repair any DTCs that may be relevant to the problem.  Second, ensure sure your fuel is clean and your supply pressure is adequate.  


A faulty high-pressure injection pump may cause your engine to fail to start. Make certain that the rail pressure is 4,000 PSI or greater. If it's less than that, it could be a result of faulty injectors. 


After ten seconds of cranking the engine, there is no smoke coming from the tailpipe. Low rail pressure is the most common cause of cranking and starting problems. When the engine is cold and at idle, injector wear can cause a slow deceleration and blue-white smoke. 


What Are DTC (Diagnostic Trouble Codes) and How Do I Check Them? 


  1. DTC P0148 indicates checking the high-pressure common rail. This indicator indicates the difference between the actual and set fuel pressures. Besides the lift pump, a problem with the fuel pressure sensor could be present. Check the fuel filter and the fuel pressure for the vehicle. 

  1. DTC P0201 – P0206 is the injector control circuit.  Ensure the injectors' resistance is more than zero but less than one ohm.  

  1. DTC P0300 – P0306 is an injector misfire. Using a scan tool, isolate each cylinder and test the fuel pressure. For each injector, it is necessary to check their contribution rates. 

  1. DTC P1223 is a leak detection code that relies on a quantity balance. If this fault occurs, you will hear a chime ten times in succession. The "wait to start" indicator light will turn on. In this case, the calculated fuel flow exceeds the anticipated fuel flow. If you receive this code, you should first check for any other codes related to fuel. Begin by addressing the codes that are already present. If there are no more codes, you can check the DTC P0148 to see if it is present. 

  1. DTC P2146 and P2149 describe low or high voltage on cylinders 1-3 and 4-6. Then check the injector wire harness, valve cover gasket, and injectors. An ohm meter should show a resistance greater than zero and less than one. 

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