The car's starter rotates slowly and feebly, which makes it difficult to start the engine. When the starter switch is turned on, the car's starter makes only a "clicking" sound and does not start.

The reason for slow cranking starter

1. Low battery or loose connection, poor contact.

2. Starter bearing is too tight or loose. The armature shaft is bent, sometimes rubbing against the poles. The brush is too dirty or wear, spring is too weak, armature and magnetic field coil are short circuit.

3. Starter switch contact ablation or coil of solenoid is short circuit.

4. The auxiliary coils of sliding armature starter are disconnected or short circuit

 Fault diagnosis 

1. The diagnostic steps are basically the same as those when the starter does not rotate. Because both failures are caused by the same factors, only to different degrees.

2. Turn on the starter switch, the starter switch just clicked. The rotation failure is usually caused by the electromagnetic control type and the sliding armature starter.

The magnetic starter, the solenoid switch is open and makes a sound of "click", but the starter does not rotate, indicating that solenoid switch coil has short circuit or bad contact, and the generated magnetic force is too small to further compress the return spring, resulting in bad contact of the main circuit.

If the coil of solenoid switch is normal, it may be the starter pinion just touches the end face of the flywheel and fails to engage while starting. If the crankshaft of the engine is rotated at an angle, the pinion will usually get stuck between the ring gear of the flywheel. If the pinion doesn't mesh in this case, the return spring is too hard.

The sliding armature starter, when the solenoid switch is turned on, the upper contact of the movable contact is closed first, the auxiliary coil is open, the armature slowly rotates and moves, and the top of the plate raises the claw block to make the movable contact also closed, the main circuit is closed, the starter rotates at high speed. If the claw shaped block in contact with the disc wears out, the claw shaped release limit plate will not lift. As a result, the lower section of the moving contact can’t close, and the main circuit will be blocked, and the car's starter rotate slowly and weakly. In addition, if the auxiliary coil is damaged or short circuit, the starter cannot rotate slowly during starting, and the starter pinion tends to stop against the end face of the vehicle starter flywheel gear ring and is not easily engage.