Symptoms

Jerks, loud burning (rattling) and insufficient engine power.

Cause – injection actuator valve

The injection actuator solenoid valve is worn or damaged. He is, similar to a mechanical injection timer, responsible for the regulation of the injection start depending on the rotational speed. Here too, the adjustment is made hydraulically. However, in a modern solution, the valve is clocked by the EDC controller. When the valve remains open – the start of injection is delayed, and when completely closed (e.g. damaged) – accelerated.

Troubleshooting and fault elimination

Perform a quick test in the event of engine jerking: remove the plug from the valve and carry out a test drive. If the engine could not be started after disconnecting the plug, connect the valve with the auxiliary line. There are, however, loud noises during this test, resulting from hard combustion (closed valve = injection start too early) at idle and at low engine speeds, the power is significantly reduced. In addition, various faults are stored in the fault memory. However, if the misfires no longer occur, it is necessary to replace the valve. You cannot forget to clear the fault memory! After switching on the ignition, voltage must be applied to the valve. The clocking takes place on the ground side and is visible on the oscilloscope in the form of a square signal. If the adjustment is accurate, the duty cycle factor decreases as the rotational speed increases. In the solenoid valve itself, you can check the resistance of the coil (required value is approx. 10-20 Oh).