If Cummins diesel engine running not stable, it will directly affect the power performance, driving comfort and economy of your vehicle, also there will be more exhausting pollution. Therefore, we have to identify the cause of the fault and systematic troubleshooting when the engine running instability.
(1) Test the fuel pressure system
Test the pressure of the fuel system with Cummins special diagnostic software INSITE when engine running at the idle speed. Comparing difference between the fuel pressure control rail and the pressure of measurement rail, if it’s more than 100bar, you need to check the whole fuel system.
(2) Check each cylinder injector
Running the engine under idle speed, test each cylinder with Cummins diagnostic software INSITE.
If any cylinder is broken, the operation of the engine sound and the change of speed is much larger than that of the other cylinder injector, indicating that there may be a problem with the fuel injector, it is recommended to test the fuel return.
In addition, you can use the INSITE software to read the engine fault code to observe whether there is a fault with the injector code.
If there is any fault, troubleshoot and clear the fault code according to the fault code tree.
(3) Check the cylinder pressure, intake and exhaust valve clearance, working conditions, whether any leaking for the air intake manifold etc.
There are many reasons for the engine running unstable, so it is necessary to analyze the actual situation in order to find out the cause of the problem and solve the problem.
As the saying goes, seven part to maintain and three part depend on repairing, only regular maintenance and inspection of various parts, so you can extend the life of your automotive. Hope the a few tips of judge fault, which is able to help you.