Symptoms of a faulty Common Rail injector?

A faulty fuel injector will almost certainly disrupt the spray of fuel into the combustion chamber. Worst case, it might even prevent it all together. Either way, it will impact vehicle performance resulting in a number of common symptoms:

1. Check engine light: if the engine is not performing as it should, it can trigger the engine management light to come on. A diagnostic scan tool will be needed to confirm the fault code.
2. Rough idle: if fuel delivery is restricted, the RPM at idle will drop resulting in a rough idle. If this falls too low, the car will eventually stall.
3. Engine knock: when the fuel is not ignited properly, because of an incorrect air-fuel mixture for example, it can cause premature detonations – these can be heard as a knock or ping from the engine.
4. Engine surge: a faulty injector may also supply too much fuel to the cylinder, resulting in engine surge. If this happens, engine revs will continue to change under constant load and throttle.
5. Engine misfire: with disrupted fuel supply, the engine’s cylinders may not be able to provide enough power to the vehicle, causing it to misfire.
6. Fuel leakage: if diesel is present on the exterior of the injector or nearby, the injector maybe damaged. Alternatively the seal may have worn through.
7. Poor fuel economy: the ECU will compensate for any faulty injectors by over-fuelling. This causes the engine to run rich, using more fuel than is needed.
8. Increased emissions: a bad injector can also result in incomplete combustion of the diesel fuel, and as such, increased emissions in diesel vehicles.