What are the common faults of car starter motors?

February 21, 2025

The starter does not turn

Circuit connection issues: Poor contact of battery terminals, open or short circuits in starter related circuits, blown fuses, damaged starter relays, poor contact of key door start contacts or plugs, etc., can all prevent the starter from receiving normal power supply and thus not turning.

Electromagnetic switch malfunction: The electromagnetic switch contacts are burned and unable to close the conductive circuit properly; The electromagnetic switch coil is open circuited, short circuited, or poorly grounded, which cannot generate sufficient electromagnetic force to drive the starter motor to operate.

Internal fault of starter motor: Short circuit, open circuit or grounding of excitation winding or armature winding, causing the starter motor to be unable to generate normal electromagnetic torque; Insulation brush grounding affects the current path; Carbon card stuck or severely worn, unable to make good contact with the commutator and unable to transmit current.

Excessive engine resistance, such as stuck internal components, small clearance between pistons and cylinder walls, and tight crankshaft bearings, makes it difficult for the starter to drive the engine to rotate.

The starter motor runs weakly

Battery issue: The battery is running low and unable to provide sufficient electrical energy; The battery has been used for too long, resulting in decreased performance, increased internal resistance, and insufficient output current.

Starter mechanical failure: The starter copper sleeve or bearing is severely worn, causing rotor eccentricity and friction with the stator, increasing operating resistance; The bending and deformation of the armature shaft can also cause the starter to become stuck during operation, consuming excessive energy.

Electrical malfunction of starter motor: severe wear of carbon brush, reduced contact area with commutator, increased contact resistance, resulting in poor current flow; Local short circuit in the excitation coil or armature coil reduces the electromagnetic torque output by the starter motor.

Starter idling

Transmission mechanism issue: The fork of the mechanical forced starter is not in the slot or the stroke adjustment is improper, which cannot drive the small gear to mesh with the flywheel ring gear; The electromagnetic switch core stroke of the electromagnetic controlled starter motor is too short, and the main circuit is connected in advance. The armature rotates at high speed when the small gear is not engaged.

Unidirectional clutch failure: The one-way clutch slips and cannot transmit the power of the starter to the engine flywheel ring gear; The one-way clutch is stuck and cannot automatically disengage after the engine starts, causing the starter to idle.

Flywheel ring gear problem: The flywheel ring gear is severely worn or damaged, causing the starter drive small gear to be unable to mesh with the flywheel ring gear normally, resulting in idling phenomenon.

Abnormal noise from starter motor

Gear wear or damage: The single gear of the starter motor and the flywheel ring gear of the engine are severely worn, and there may be a collision or "click" sound when starting; The broken teeth in the starter drive gear or flywheel ring gear can also cause abnormal noise during startup.

Installation issue: The fastening bolts between the starter and engine are loose, which can cause abnormal impact noise during startup; Improper installation of the starter motor can result in poor meshing between the starter gear and the flywheel ring gear, which can also cause abnormal noise.

Internal component failure: The starter rotor bearing is loose, resulting in excessive radial clearance between the rotor shaft and the bearing, and abnormal noise caused by collision between the rotor body and the magnetic pole; Excessive wear of the electric brush and poor contact with the commutator can produce buzzing or other abnormal sounds.

The starter motor still runs after releasing the start switch

Electromagnetic switch malfunction: The electromagnetic switch contacts are sintered and cannot disconnect the circuit in a timely manner after releasing the start switch; The return spring of the electromagnetic switch has failed, preventing the electromagnetic switch from resetting normally, resulting in the starter motor continuing to operate with power on.

Ignition switch malfunction: The internal contacts of the ignition switch are stuck or damaged, which cannot correctly control the on/off of the starter circuit, causing the starter to continue running even after releasing the switch.

Author:

Mr. yin chang

E-mail:

yinchanghaoshuai@163.com