General information about the engine starting system and precautions (BMW 5 Series E28)

The sole function of the starting system is to crank the engine at a sufficient speed to start the engine.

The starting system consists of a battery, starter, starter solenoid, ignition switch and wiring. The solenoid is mounted directly to the starter. The starter/sensor assembly is mounted to the bottom of the engine, near the clutch housing.

When the ignition key is turned to the "START" position, the starter solenoid is activated via the starter control circuit. The starter solenoid then connects the battery to the starter and engages the starter pinion with the flywheel rim. The battery supplies electrical energy to the starter, which turns the engine.

On some models with manual transmission, the starter only engages when the clutch pedal is depressed. On vehicles with automatic transmission, the starter only engages when the transmission shift lever is in the "P" (Park) or "N" (Neutral) position.

When working on the engine starting system, always disconnect the negative battery cable.

[The original article is available on the website: «BMWMAN»]