Diesel Injectors Common Rail and Older Cummins injectors

Diesel injectors have come a long way over the years. The pressures have gotten progressively higher over the years to meet stricter emissions standards. From a simple single spring low pressure injector they progressed to a dual spring injector to reduce engine noise. And pressure was increased. Then a sensor was added to aid in computer controlled timing. When high pressure common rail injection came along, very precise solenoids were added. To make the injection pulses even faster, piezo solenoids were used. By this time, pressures were pushed over 2000 bar. Strangly, the newer piezo technology might Not be the future And some New diesels are using solenoid valves.

Sometimes injectors fail slowly And start backflowing. Other times, the internal valve completely fails And causes the whole common rail to stop building pressure. Either way, it's time to replace the injector.

Here are the injectors: