What are the key points for troubleshooting diesel engine starter motor failures?
2 Answers
Key points for troubleshooting diesel engine starter motor failures: 1. Assessing the starter motor condition: The standard procedure for checking starter motor functionality involves energizing it to observe whether it can operate, whether the rotational speed is sufficiently high, and whether the sound is uniform and powerful. 2. Diagnosing abnormal noises: To eliminate starter motor abnormal noises, it's essential first to determine when the fault occurs, as noises caused by different factors manifest at different times. 3. Evaluating the electromagnetic switch: The operational characteristic of electromagnetic switch-type starter motors is their electromagnetic control method, which utilizes electromagnetic force to drive the shift fork for diesel engine starting. Failure of the starter motor to rotate is mostly caused by internal open circuits, grounding, short circuits, or electromagnetic switch malfunctions.
When the diesel engine starter fails, I first ensure the battery voltage is above 11.5 volts. If the voltage is low, charge or replace the battery, as starting issues often begin here. Next, check all cable connections for looseness, especially the positive and negative terminals, by shaking them to see if the contact is good; looseness can easily cause intermittent faults. Then test the starting signal by using a multimeter to check if the key switch output is normal. A missing signal may indicate a relay issue, with burnt relay contacts being a common cause. You can swap with another relay to test this. If the signal is normal but the motor doesn’t turn, directly apply 12 volts to the motor’s positive terminal for testing. If it moves, the problem lies in the control circuit; otherwise, it’s an internal motor issue like worn carbon brushes or seized bearings requiring professional repair. Always prioritize safety by disconnecting the battery’s negative terminal first to avoid short-circuit risks. Finally, remember to inspect these components every six months to reduce unexpected failures.
