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How a Common Rail Diesel Injector Works and Common Failure Points

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We posted this a while back. Thought it'd be a good idea to repost it for those of you who haven't seen it before...

We, at Engineered Diesel, created this video to help our customers have a better understanding of how a common rail diesel injector works, which makes it easier to understand why they fail. This video also points out common failure points within the injectors. If you are experiencing ANY of these symptoms, you may need new injectors.


Video Summary:

♦How a Common Rail Diesel Injector Works:

1. High pressure fuel enters the injector. Pressure is equal throughout the injector.
2. When the solenoid is energized, it pulls the control plunger upwards.
3. The control plunger releases a small amount of fuel which creates a pressure differential, allowing the pintel to come off of its seat.
4. The pintel moves upwards and allows fuel to inject into the cylinder.
5. Injector current is shut off.
6. Ball reseats.
7. Pressure ABOVE the needle increases and pushes the nozzle closed.


♦Common Failure Points & Symptoms:

1. High-pressure ball seat erodes, causing high return flow.
-Symptom: This causes extended crank or will not start. If erosion get bad enough, injector will not shut off.
2. Nozzle erosion causes seapage.
-Symptom: This causes poor fuel economy and/or blueish white smoke at idle.
3. Solenoid coil windings short out.
-Symptom: This causes a misfire.
4. Debris can build up around the control plunger.
-Symptom: This can cause the injector to stick open.

*This is not everything that can go wrong, just the most common issues we have seen.

Check out the video for a better visual.

How a Common Rail Diesel Injector Works and Common Failure Points - Engineered Diesel - YouTube

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