The starter stops performing the functions assigned to it in the event of a failure of the solenoid relay. Unlike other devices of this purpose, it not only closes the electric circuit with its contacts, but also provides mechanical engagement of the bendix and the flywheel crown at the time the engine starts. Such a twofold purpose, perhaps, is no longer found in any car assembly. Given the importance of the starter solenoid relay for normal operation of the machine, knowledge of its purpose and device will not be superfluous, and the theory of repair will probably come in handy in practice.
Device
Structurally, the traction relay, which is what it is called in all manuals, is a powerful electromagnet. From most solenoids it is distinguished by the presence of two windings, retracting and holding. The relay has powerful, normally open contacts and a rod on which a metal plug is mounted.
The retractor is made in the form of a complete, independent unit and installed on the starter. The relay case is cylindrical, made of metal. On the back side it is covered by a cover made of dielectric material, on which 3 terminals are fixed. Two of them are designed to power the starter, the third is the retractor coil of the relay. The case can be either collapsible or not, depending on the manufacturer and model. The return of the starter solenoid relay to its original position is carried out by a powerful spring.
Principle of operation
Why do you have to install a traction relay? The fact is that the starter consumes a lot of current. These are dozens, or even hundreds of amperes in full braking mode. Therefore, connecting it directly to the ignition switch will not work, its contacts will burn out immediately. It is necessary to use an additional relay. It must have powerful contacts, and therefore, a large power consumption, which will create an additional load on the battery. In addition, questions would arise with connecting the starter wires having a large cross section. The starter retractor, thanks to its design, is devoid of these drawbacks.
Now directly the principle of work. When the ignition key is turned to the position that includes the starter, a plus is applied to the retractor winding. The relay operates and closes the starter power circuit with its contacts. But that is not all. Structurally, the retractor winding is connected in series with the starter. This prevents excessive current consumption at the first moment. Then the retracting winding is shunted by its own contacts and disconnected, and the relay remains in operation due to the possessing one. It is not so powerful, which means it consumes less current. Due to the fact that the solenoid relay is installed directly on the starter, it was possible to solve the problem with the connection, it took only one long wire of large cross section.
Simultaneously with the electric, the mechanical part of the relay starts to work. The retractor rod moves back together with the core. The fork moves forward, the bendix engages with the ratchet ring. The starter starts to rotate the engine crankshaft.
Retractor Malfunctions
All damage to the traction relay is usually associated with long-term operation and large mechanical as well as current loads. First of all, the following malfunctions can be distinguished:
- Depreciation of electrical contacts, "nickels", as they are called by experts. Most often they “burn out” under the influence of high currents.
- Open or short circuit relay coil.
- Return spring fault.
- Damage to moving elements.
With any of the listed faults, starting the engine will be difficult or even impossible. True, some of them can be fixed without significant costs. For example, on VAZ cars, the starter retractor relay is collapsible, and therefore repairable.
Symptoms
A traction relay is that rare case when you can almost reliably establish the cause of a malfunction by symptoms. The main ones are:
- lack of reaction of the starter to turn the key;
- the starter retractor snaps, but there is no crankshaft rotation;
- starter anchor turns idle;
- the bendix does not return to neutral after starting the engine.
Despite the fact that in most cases the cause of the malfunction is obvious, it is advisable to verify this.
Retractor Check
Diagnostics of the element is quite effective and does not require scarce tools and sophisticated measuring instruments. Moreover, it does not take much time, since it is possible to check the starter's retractor relay without dismantling it. Consider the main verification methods:
- When turning the key, a characteristic click of the retractor is not audible. In this case, in addition to the traction relay, the ignition switch and the wiring can be faulty. This can be precisely determined using a warning lamp. With one contact it must be connected to the "mass" of the car, with the other - to the retracting winding (flat contact on the relay cover). We put the ignition key in the "starter" position. If the lamp is on, the problem is in the traction relay. Otherwise, you need to look for other reasons. If you have a multimeter, you can check the relay by measuring the voltage. To do this, connect its probes instead of a warning lamp.
- Often when you try to start the car you hear clicks of the retractor, but the starter does not turn. There may also be several reasons, ranging from a discharged battery to relay contacts. It’s easy to make sure. It is enough to close the contacts of the starter circuit (two large terminals on the retractor cover). Experts do this right on the car, but in the absence of skills, it is better to remove the starter, it’s more convenient and, most importantly, safer. If, when the contacts are closed by a conductor of the appropriate cross section, the starter starts to work, which means that the "pyataks" are burnt out, it will be necessary to disassemble or replace the retractor.
Relay Removal
After the malfunction is localized and the failure of the retractor is reliably established, you can proceed to dismantle it. It is produced in the following sequence:
- Remove the terminals from the battery.
- Remove the starter.
- Using a 13 wrench, unscrew the nut of the wire terminal of the brush assembly.
- Having unscrewed 2 bolts, disconnect the retractor from the starter. In this case, you need to ensure that the core remains inside.
Now you can start repairing the starter solenoid relay. True, this is possible only if it is collapsible.
Relay repair
The complexity of this process is highly dependent on the vehicle model and the nature of the damage. In this case, the restoration of the operation of the contacts will be considered using the example of the starter solenoid relay 2109. The repair sequence is as follows:
- Remove relay from starter.
- Remove the two bolts on its back cover.
- Solder both contacts on the cover.
- Remove it, access to contacts is opened.
- Remove them by unscrewing two nuts at 13.
- The contacts are well cleaned of carbon deposits. If necessary, correct deformation caused by overheating.
- Assemble in the reverse order.
It is worth noting that the above example is one of the few cases when it is worth repairing the retractor. The fact is that it is difficult to find spare parts for it. Therefore, in most cases, the problem is solved by replacing the starter solenoid relay with a new one.
Conclusion
Now on sale are the so-called gear starters. They are not put at the factory, but there is no guarantee that the previous owner of the car did not. Solenoid relays on them are not interchangeable. Therefore, before buying a new one, you must first clarify which starter is on the car.