Starters
CHECKING THE STARTER
You will find useful information and important tips on the subject of vehicle starters here.
Since an internal combustion engine cannot start by itself, a functioning starter is essential for a roadworthy vehicle. Malfunctions can be caused, for example, by incorrect connections, faulty solenoid switches or a damaged single-pinion gear. Learn everything about possible problems and how you can remedy the individual cases here.
Important safety note
The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their day-to-day work. The information provided on this website is intended for suitably qualified personnel only.
TABLE OF CONTENTS
STARTERS: BASICS
Internal combustion engines cannot start themselves, they have to be started with external energy. This starting procedure can either be electrical, hydraulic or pneumatic.
Electric motors, usually referred to as starters, are used for this purpose in most vehicles. Since high friction and compression resistances must be overcome during the starting process, the DC series motor is particularly suitable as a starter motor, due to its high initial torque.
DESIGN AND FUNCTION OF THE STARTER: FUNCTION
A starter motor is usually composed of the following assemblies:
- Electric starter motor
- Engaging relay (solenoid switch)
- Drive-end bearing with single-pinion gear
The electric starter motor consists in principle of a tubular pole housing in which the pole shoes, excitation windings and permanent magnets are housed. The electrical armature with armature winding is situated in this pole housing. The engaging relay, also known as a solenoid switch, is a combination of a relay and solenoid magnet, and is mounted at the top in the drive-end bearing. The single-pinion gear with pinion, free-running roller, engaging lever, carrier and in-line spring is situated in the drive-end bearing.
Function
The engaging relay is actuated when the motor is started via the ignition lock. The flow of current in the pull-in and hold-in winding attracts the relay armature. This actuates the engaging lever and pushes the carrier unit with pinion and freewheel against the ring gear of the engine flywheel. Once the pinion is fully engaged, the contact bridge in the engaging relay completes the main circuit to the starter motor. The starter is switched on and turns.
STARTER FAULTY: SYMPTOMS
The following symptoms may indicate a fault in the starter if the motor fails to start:
- No response when actuating the ignition switch
- The starter "clacks", but does not engage
- The starter audibly turns, but without the motor engaging
CAUSES OF FAULTY STARTERS: CAUSE OF FAILURE
A starter malfunction can have different causes:
- Electrical connections faulty
- Solenoid switch (engaging relay) stiff or faulty
- Electric motor damaged electrically
- Single-pinion gear, starter pinion or freewheel damaged
NOTICE
A fault-free supply of power to the starter is imperative for its successful function. The vehicle battery and the positive and ground supply of the starter should be included in the fault diagnostics.
TESTING THE STARTER: TROUBLESHOOTING
Electrical faults in the starter are mainly caused by overloads. This can manifest itself in ground and winding short circuits in the field and armature winding, but sometimes also in the coils of the control elements (solenoid switch). Carbon brushes and collectors are subjected to high loads and are more susceptible to faults than the alternator. While, for example, clamping carbon brushes in the alternator do not cause voltage to arise and thus relieve the alternator, clamping carbon brushes in the starter leads to the formation of significant arcs due to the high currents. These arcs often destroy the collector. A multimeter and a clip-on ammeter are required for troubleshooting. Fault sources (such as the pinion) can, however, also be located through acoustic perception. Please also refer to the technical info: "Ground (31)".
The starter does not turn when the ignition switch is actuated.
| CAUSE: | REMEDY: |
|---|---|
| Switch on lighting (low beam).
|
|
| Solenoid switch does not energize:
|
|
| Solenoid switch energizes:
|
|
Starter does not turn when the battery cable is connected directly to the contact screw below connection terminal 30, or the starter turns too slowly, or does not crank the engine.
| CAUSE: | REMEDY: |
|---|---|
| Carbon brushes worn | Replace carbon brushes |
| Carbon brushes clamping | Clean carbon brushes and guides of the brush brackets |
| Springs not supplied with sufficient voltage. Carbon brushes not contacting | Replace springs |
| Collector contaminated | Clean collector |
| Collector grooved or burned | Refurbish or replace starter |
| Armature or field winding faulty | Refurbish or replace starter |
Starter engages and energizes. The motor only turns jerkily or not at all.
| CAUSE: | REMEDY: |
|---|---|
| Battery discharged | Charge battery, check |
| Poor conductance of electricity due to loose or oxidized connections | Clean battery poles and connections and tighten |
| Carbon brushes clamping | Clean carbon brushes and guides of the brush brackets |
| Carbon brushes worn | Replace carbon brushes |
| Collector contaminated | Clean collector |
| Collector grooved or burned | Refurbish or replace starter |
| Armature or field winding faulty | Refurbish or replace starter |
Drive pinion does not disengage. Starter engages and energizes. The motor only turns jerkily or not at all.
| CAUSE: | REMEDY: |
|---|---|
| Drive pinion faulty | Replace drive pinion |
| Ring gear on the flywheel faulty | Rework ring gear, replace if necessary |
Drive pinion does not disengage.
| CAUSE: | REMEDY: |
|---|---|
| Pinion or steep thread contaminated or damaged | Refurbish or replace starter |
| Solenoid switch faulty | Replace solenoid switch |
| Return spring worn or broken | Replace return spring |
Starter continues to run after release of the ignition switch.
| CAUSE: | REMEDY: |
|---|---|
| Ignition switch or relay faulty | Switch the engine off immediately! Check switch and relay, and replace if necessary |
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