What are the causes of a weak starter?
2 Answers
Car starter weakness is mainly caused by insufficient battery charging, poor wiring or connections resulting in excessive resistance, leading to reduced current. The following are diagnostic methods for a weak starter: 1. Use a conductor to bridge the two terminals on the starter switch. If the starter speed increases significantly, it indicates poor contact at the starter switch contacts, increasing resistance. If the starter speed does not change, check whether the battery is sufficiently charged, whether the brush wear is excessive, and whether the brush spring is too weak. 2. Internal armature coil or field coil partial short circuits in the starter are also one of the causes of a weak starter. Check the starter circuit wiring and connections, as poor wiring and loose, corroded connections will generate heat due to increased resistance. 3. Internal mechanical faults in the starter can also affect the normal operation of the starter. If the power supply, starter circuit, and starter switch are all intact, check whether the starter bearings are too tight or whether the armature shaft is bent, causing friction between the armature and the magnetic poles. 4. Under low-temperature conditions, the internal resistance of the battery will also increase, the terminal voltage will decrease, and the engine friction resistance will increase, which can also cause symptoms of a weak starter.
I've encountered this issue before where the starter motor turns weakly and can't crank the engine. I checked the battery and found insufficient charge leading to inadequate power supply. The terminal posts sometimes get corroded or oxidized, preventing current from passing through. Additionally, if the starter motor's internal brushes are severely worn, poor contact will also result in weak performance. I recommend checking for loose wiring connections, especially at the ground wire attachment point. Also, if the engine oil is too thick or the engine itself has excessive resistance, the starter has to work harder to turn. This situation is particularly common during cold winter starts – remember that preheating the oil helps a lot.
