In practice, there are only 10 reasons why the starter clicks but does not turn. To find and fix a malfunction, it is not necessary to visit a service station. It is enough to study this material, arm yourself with a pair of keys and a multimeter. Some points are described only in general terms, as there are links to more detailed materials on them. Now you will find out what clicks in the starter, why it does not turn, where and how to look for a malfunction, and how to repair it yourself.
An automobile starter is a powerful electric motor that is connected to the flywheel of an internal combustion engine using a solenoid relay. This is what you hear in 80% of cases when the starter clicks but does not turn. The solenoid relay is located directly on the starter and has the following device.
- Retractor armature.
- Retractable winding.
- Retaining winding.
- Compression spring.
- Contact node.
- Contact spring.
- Conclusions of power contacts.
- Contact plate.
- Return spring.
Together with the starter it looks like this.
Working principle. When the ignition key is turned to the “start” position, the retracting winding (2) is activated. Under the action of electromagnetic force, the armature (1) is pulled inward. All springs are compressed, and the plate (9) closes the power contacts (6). Due to the movement of the armature in the starter, the overrunning clutch moves to the engine flywheel. The starter connects to the engine and is ready to go.
Through the power contact (8), the starter rotor receives starting current from the battery. At the same time, the holding winding (3) is activated to ensure a reliable connection between the starter motor and the engine flywheel. The retracting winding is de-energized. After the engine has started, the driver releases the ignition key. The holding winding (3) is de-energized. All springs of the retractor relay are unclenched. The power supply to the starter is turned off, and it is disconnected from the flywheel.
In total, the retractor relay (serviceable) performs 5 functions:
- Connects the starter to the flywheel of an internal combustion engine.
- Holds this connection securely as long as the driver holds the ignition key in the "start" position.
- Automatically supplies starting current from the battery to the starter motor.
- Automatically stops the inrush current at the right time.
- Disconnects the starter from a running internal combustion engine.
When the starter clicks, it is nothing more than a triggered retractor winding, due to which, through a simple mechanism, the overrunning clutch moves to the flywheel.
The cause of clicks can be not only the retractor relay. But most often it is this node that is to blame.
10 problems that cause the starter to click but not turn
In total, there are 10 reasons why the starter clicks but does not turn:
- Discharged battery.
- The terminals on the battery are oxidized.
- Bad mass.
- Unreliable contact on the power outputs of the starter.
- The holding winding of the solenoid relay does not work.
- There is no contact in the switching unit of the solenoid relay.
- Starter brush wear.
- Rotor winding failure.
- The starter is sticking due to mechanical problems.
- Overrunning clutch is faulty.
Let's consider these malfunctions in more detail: symptoms, diagnostics, repair.
1. Discharged battery
To operate the retracting winding, a lot of energy is required. A discharged battery is quite capable of providing this. But when retraction occurs, the starter requires a large starting current to operate. If the battery can't deliver it, the starter makes a clacking noise but doesn't spin.
When the battery is completely discharged, the energy can only be enough for a single operation of the retracting winding. After that, the battery sits down completely. We hear one click and nothing else happens. The voltage of the on-board network drops sharply. The engine cannot be started.
If the problem looks as described, check the battery. This can be done with a multimeter or a load plug.
There are several detailed materials on charging the battery on the site:
- Recharging a calcium battery - a master class
- How to charge a maintenance-free battery
- How to charge an AGM battery
- How to charge a GEL battery
- How to charge a calcium battery
If the battery is charged, keep looking for other causes.
2. Battery terminals oxidized
When the battery terminals oxidize, even a well-charged battery cannot provide normal starting current to operate the starter. How this problem looks like, and how to deal with it, is described in detail in the material “Battery terminals are oxidized”.
3. Bad "mass"
"Minus" from the battery to the starter comes through the "mass". Usually this is a thick wire that goes from the “minus” of the battery to the body or engine. Thus, a negative potential is constantly present on the starter housing and the solenoid relay. Carefully inspect the ground wire. Maybe it's damaged. Although most often due to dirt and oxides there is no good contact of this wire with the engine. Contacts need to be cleared. Replace the entire wire if necessary.
4. Unreliable contact on the power outputs of the starter
The "plus" for power supply to the starter comes from the battery to one of the terminals on the solenoid relay. Then it passes through the plate of the switching unit, and through the second power output enters the starter windings. If it is structurally located at the bottom of the engine compartment, these contacts are guaranteed to have dirt and oxides. Before disassembling the starter and looking for the problem more deeply, make sure you make contact.
5. The holding winding of the solenoid relay does not work
There are two faults in the holding winding. It may either not work at all, or hold with insufficient strength. When a winding breaks, it does not work at all. An inter-turn short circuit causes the winding to generate an electromagnetic field that is too weak to provide a reliable connection between the starter and the engine flywheel.
How to check this on your own, read the article "Checking the starter retractor relay".
6. There is no contact in the switching unit of the retractor relay
If the starter makes only one clicking sound when the ignition key is turned to the “start” position, and nothing else happens, this may indicate a lack of contact in the switching unit. It provides power to the starter. Accordingly, if there is no contact, rotation does not occur.
Diagnosis and repair of this malfunction is also described in the material on checking the retractor relay at the link above.
7. Starter brush wear
The next point on the power supply line of the starter is the current-carrying brushes. If they are worn out, destroyed, or jammed in the guides, then the electric motor will not work. The retractor relay, at the same time, can properly perform its functions and click when the ignition key is turned.
To check the brushes, they must be removed from the starter. The brush assembly is a replaceable part, so repairs are not very difficult.
8. Rotor winding failure
The "terminus" of inrush current is the rotor windings. There can also be two faults here. Open or interturn circuit. To test the starter rotor, all you need is a multimeter. Each winding is brought out by two contacts to adjacent collector lamellas. To find a break, you need to ring out with a multimeter. To find the interturn circuit, it is necessary to measure the resistance of each winding and compare the readings of the device with each other. If there is an interturn short circuit in any of the windings, its resistance will be much lower than that of the others.
To eliminate such malfunctions, you will either have to replace the rotor with a new one, or give it to specialists for rewinding and balancing.
9. Starter sticking due to mechanical problems
In order for the electric motor to start rotating, not only the starting current is needed. The rotation of the rotor shaft should not be hindered by anything. The main sources of problems: moisture, corrosion, dirt, dust, worn bushings. These problems are described in detail in the material "Why the starter turns badly". All of them are easily eliminated by cleaning or replacing parts.
10. Faulty overrunning clutch
The starter freewheel has two functions:
- Transfers torque from the starter shaft to the engine flywheel.
- Disengages the gears when the engine starts and the engine speed increases.
When the freewheel wears out, when trying to start the engine, we hear clicks of a slightly different nature than in other cases. In addition to clattering sounds, an unpleasant metallic rattle is added to the "orchestra". This symptom indicates that the freewheel is slipping. Torque is not transmitted from the starter shaft to the flywheel. Accordingly, the engine does not start.
To eliminate the malfunction, it is enough to replace the worn overrunning clutch with a new one.
If the starter makes clicking and metallic sounds, it rotates itself, but the engine does not turn, this is a freewheel. In all other cases, the problem must be sought methodically and consistently. First check the battery, then all the power contacts and wires. If the fault cannot be identified, look at the solenoid relay and the starter power supply line.