BMW starting system and its working procedure?

There are many parts which functions when you turn over your BMW.This all parts are indicated as parts of starting system,
Starter and battery are main parts of starting system.
Go through the details to understand you BMW cars starting system.

Description & Operation

Fig. Exploded view of a typical Bosch® starter

The battery and starter motor are linked by very heavy gauge electrical cables designed to minimize resistance to the flow of current. Generally, the major power supply cable that leaves the battery goes directly to the starter, while other electrical system needs are supplied by a smaller gauge cable. During starter operation, the positive (+) battery power flows from the battery to the starter solenoid, and the starter is grounded through the engine which is grounded by the battery's negative ground strap.

The starter is a specially designed, direct current electric motor capable of producing a great amount of power for its size. What allows the motor to produce a great deal of power is its tremendous rotating speed. It drives the engine through a tiny pinion gear (attached to the starter's armature), that drives the very large flywheel ring gear at a greatly reduced speed. Another factor allowing it to produce so much power is that only intermittent operation is required of it. Thus, little allowance for air circulation is necessary, and the windings can be built into a very small space.

The starter solenoid is an electromagnetic device that is triggered by the small current supplied by the start circuit of the ignition switch. This electromagnetic action moves a plunger that mechanically engages the starter gear and closes the high amperage switch connecting the starter to the battery. The starting switch circuit is part of the ignition switch. The starting circuit wiring includes a safety circuit, such as a neutral safety switch, or clutch pedal switch, that prevents the engine from being started with the transmission engaged. Also included in the starting circuit is the wiring necessary to connect these in series with the starter solenoid.

The pinion, a small gear, is mounted to a one-way drive clutch. This clutch is splined to the starter armature shaft. When the ignition switch is moved to theSTART position, the solenoid plunger slides the pinion toward the flywheel ring gear via a collar and spring. If the teeth on the pinion and flywheel match properly, the pinion will engage the flywheel immediately. If the gear teeth butt one another, the spring will be compressed and will force the gears to mesh as soon as the starter turns far enough to allow them to do so. As the solenoid plunger reaches the end of its travel, it closes the contacts that connect the battery to the starter, and then the engine is cranked.

As soon as the engine starts, the flywheel ring gear begins turning fast enough to drive the pinion at an extremely high rate of speed. At this point, the one-way clutch begins allowing the pinion to spin faster than the starter shaft so that the starter will not operate at excessive speed. When the ignition switch is released from the start position, the solenoid is de-energized, and a spring pulls the gear out of mesh, interrupting the current flow to the starter.

Some starters employ a separate relay, mounted away from the starter, to switch the motor and solenoid current on and off. The relay replaces the solenoid electrical switch, but does not eliminate the need for a solenoid mounted on the starter used to mechanically engage the starter drive gears. The relay is used to reduce the amount of current the start position of the ignition switch must carry.

WARNING

Never compromise personal safety when working with a vehicle's electrical system.

The starter motor assembly consists of two basic components, the starter motor and the starter relay. Some manufacturers prefer to separate the relay from the starter motor, others prefer to combine the two into one unit. The Bosch® starter motor found on BMW models is a combined unit. The relay used on these starter motor assemblies actually serves two purposes. The relay is used to:

Act as a switch to complete a high amperage electrical circuit between the battery and the starter motor.

Engage the starter motor pinion gear with the flywheel ring gear.

The two most common symptoms of a combination starter motor failure are:

Nothing happens when the ignition key is turned to START .

A clicking noise is heard when the ignition key is turned to START .

1. Assuming the battery is fully charged and all of the battery cables are properly attached and their connections clean, if nothing happens when the key is turned to START most likely the starter motor solenoid has failed. In an emergency situation a remote starter switch could override the relay and allow the starter to function temporarily.
2. If a clicking noise is heard, that's an indication that the solenoid is engaging, but the electric motor portion of the starter motor has failed. In an emergency situation, sometimes the starter motor can be rapped sharply with a screwdriver or hammer handle which may startle the starter motor enough to function temporarily.

If the starter motor operation is intermittent, check the operation of the ignition switch. If your starter motor is acting up, use the following steps to troubleshoot the cause and replace the starter motor as necessary. A starter motor replacement is much easier to do in an evening after work or on a day off. It's not something you'll want to be doing on the side of the road.

This details will help you.

Thanks.

For more car related problem troubleshooting:---

This are the sections, you can go through and click the link to read its troubleshooting.

---------

The car will not start?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-start.html

-----------------

Car will not crank?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-crank.html

-----------

Car has no spark?

http://schematicsdiagram.blogspot.com/2011/06/car-has-no-spark.html

-------------

How to troubleshoot car battery?

http://schematicsdiagram.blogspot.com/2011/06/how-to-troubleshoot-car-battery.html

-----------------

How to test starter solenoid?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-starter-solenoid.html

--------------------

How to test cars starter?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-cars-starter.html

How to replace starter in car?

http://schematicsdiagram.blogspot.com/2011/06/how-to-replace-starter-in-car.html

-----------

car will turn over but will not start?

http://technoanswers.blogspot.com/2011/05/car-will-turn-over-but-will-not-start.html

-----------------

Car wont start?

http://howtobyme.blogspot.com/2011/10/car-wont-start.html

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How to replace battery on 2005 BMW 325?

Battery Removal & Installation

When it becomes necessary to replace the battery, select one with sufficient cold cranking amps, with a rating equal to or greater than the battery originally installed. Deterioration and just plain aging of the battery cables, starter motor, and associated wires makes the battery's job more difficult in successive years. As the vehicle ages, the wiring becomes slightly less efficient causing an increase in electrical resistance. Because of this condition, when replacing the battery, it is suggested to choose a battery with a greater capacity.

CAUTION

When replacing a battery, ALWAYS disconnect the negative battery cable first, then disconnect the positive battery cable. When connecting a battery, ALWAYS connect the positive cable first and then the negative battery cable.

WARNING

The E36 models with an electrically operated convertible top require a special battery. This battery is designed to withstand excessive vibration generated by the opening and closing of the top. A battery not designed for this application will be subject to premature failure.

E36 Models

1. Open the luggage compartment lid and pull back the trunk lining on the right side for the 3 Series models. On Z3 models the battery is centrally located and if installed, the access cover must be removed.
2. Disconnect the negative battery cable, then disconnect the positive battery cable.
3. Remove the batter hold down bracket and remove the battery.
4. The balance of the installation is in reverse order of removal, making sure to connect the positive battery cable first, then the negative battery cable.
5. Recode the radio.
6. If equipped with electrically operated windows reinitialize the finger jam protection. To do so:
   1. Enter the vehicle and close the doors.
   2. Turn the ignition switch to the ON position.
   3. Raise the window until fully closed and hold the switch in the closing position for an additional 5 seconds.

Fig. The battery hold down bracket clamps down on the base of the battery

-------------

For more car related problem troubleshooting:---

This are the sections, you can go through and click the link to read its troubleshooting.

---------

The car will not start?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-start.html

-----------------

Car will not crank?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-crank.html

-----------

Car has no spark?

http://schematicsdiagram.blogspot.com/2011/06/car-has-no-spark.html

-------------

How to troubleshoot car battery?

http://schematicsdiagram.blogspot.com/2011/06/how-to-troubleshoot-car-battery.html

-----------------

How to test starter solenoid?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-starter-solenoid.html

--------------------

How to test cars starter?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-cars-starter.html

How to replace starter in car?

http://schematicsdiagram.blogspot.com/2011/06/how-to-replace-starter-in-car.html

-----------

car will turn over but will not start?

http://technoanswers.blogspot.com/2011/05/car-will-turn-over-but-will-not-start.html

-----------------

Car wont start?

http://howtobyme.blogspot.com/2011/10/car-wont-start.html

----------

Jump Starting Battery on 2005 BMW 325?

When battery goes weak or dead, the car will not start.In that case the jump starting the battery is required to start the car.
The details are as follows :---

Jump Starting A Dead Battery

Whenever a vehicle is jump started, precautions must be followed in order to prevent the possibility of personal injury. Remember that batteries contain a small amount of explosive hydrogen gas which is a by-product of battery charging. Sparks should always be avoided when working around batteries, especially when attaching jumper cables. To minimize the possibility of accidental sparks, follow the procedure carefully.

Fig. Connect the jumper cables to the batteries and engine in the order shown

WARNING

NEVER hook the batteries up in a series circuit or the entire electrical system will go up in smoke, including the starter!

Vehicles equipped with a diesel engine may utilize two 12 volt batteries. If so, the batteries are connected in a parallel circuit (positive terminal to positive terminal, negative terminal to negative terminal). Hooking the batteries up in parallel circuit increases battery cranking power (amperage) without increasing total battery voltage output. Output remains at 12 volts. On the other hand, hooking two 12 volt batteries up in a series circuit (positive terminal to negative terminal, positive terminal to negative terminal) increases total battery output to 24 volts (12 volts plus 12 volts).

E30 Models

1. Make sure that the voltages of the 2 batteries are the same. Most batteries and charging systems are of the 12 volt variety.
2. Pull the jumping vehicle (with the good battery) into a position so the jumper cables can reach the dead battery and that vehicle's engine. Make sure that the vehicles do NOT touch.
3. Place the transmissions of both vehicles in Neutral (MT) or P (AT), as applicable, then firmly set their parking brakes.

NOTE

If necessary for safety reasons, the hazard lights on both vehicles may be operated throughout the entire procedure without significantly increasing the difficulty of jumping the dead battery.

1. Turn all lights and accessories OFF on both vehicles. Make sure the ignition switches on both vehicles are turned to the OFF position.
2. Cover the battery cell caps with a rag, but do not cover the terminals.
3. Make sure the terminals on both batteries are clean and free of corrosion or proper electrical connection will be impeded. If necessary, clean the battery terminals before proceeding.
4. Identify the positive (+) and negative (-) terminals on both batteries.
5. Connect the first jumper cable to the positive (+) terminal of the dead battery, then connect the other end of that cable to the positive (+) terminal of the booster (good) battery.
6. Connect one end of the other jumper cable to the negative (-) terminal on the booster battery and the final cable clamp to an engine bolt head, alternator bracket or other solid, metallic point on the engine with the dead battery. Try to pick a ground on the engine that is positioned away from the battery in order to minimize the possibility of the 2 clamps touching should one loosen during the procedure. DO NOT connect this clamp to the negative (-) terminal of the bad battery.

CAUTION

Be very careful to keep the jumper cables away from moving parts (cooling fan, belts, etc.) on both engines.

1. Check to make sure that the cables are routed away from any moving parts, then start the donor vehicle's engine. Run the engine at moderate speed for several minutes to allow the dead battery a chance to receive some initial charge.
2. With the donor vehicle's engine still running slightly above idle, try to start the vehicle with the dead battery. Crank the engine for no more than 10 seconds at a time and let the starter cool for at least 20 seconds between tries. If the vehicle does not start in 3 tries, it is likely that something else is also wrong or that the battery needs additional time to charge.
3. Once the vehicle is started, allow it to run at idle for a few seconds to make sure that it is operating properly.
4. Turn ON the headlights, heater blower and, if equipped, the rear defroster of both vehicles in order to reduce the severity of voltage spikes and subsequent risk of damage to the vehicles' electrical systems when the cables are disconnected. This step is especially important to any vehicle equipped with computer control modules.
5. Carefully disconnect the cables in the reverse order of connection. Start with the negative cable that is attached to the engine ground, then the negative cable on the donor battery. Disconnect the positive cable from the donor battery and finally, disconnect the positive cable from the formerly dead battery. Be careful when disconnecting the cables from the positive terminals not to allow the alligator clips to touch any metal on either vehicle or a short and sparks will occur.

E36 Models

Fig. The remote positive battery terminal is used for jump starting

Fig. Open the hood and lift up the protective cover to expose the jump post for the positive (+) lead of the jumper cable

Fig. Attach the jumper cable's negative (-) lead to the negative (-) jump post, and the positive (+) lead to the positive (+) jump post

BMW provides a positive and negative jump start post in the engine compartment on the passenger's side. The positive jump start post is located underneath a protective plastic cover with a large + symbol cast into the cover. To jump start the vehicle using the under hood battery posts proceed as follows:

1. Verify that the vehicle used to supply battery voltage has a 12 Volt system with a similar sized battery, and correctly identify the positive and negative battery terminals.
2. Pull the jumping vehicle (with the good battery) into a position so the jumper cables can reach the dead battery and that vehicle's engine. Make sure that the vehicles do NOT touch.
3. Place the transmissions of both vehicles in Neutral (MT) or P (AT), as applicable, then firmly set their parking brakes.

NOTE

If necessary for safety reasons, the hazard lights on both vehicles may be operated throughout the entire procedure without significantly increasing the difficulty of jumping the dead battery.

1. Properly connect the positive battery jumper cable lead to the vehicle used to supply the required voltage. The red lead of the jumper cable is the positive battery lead.
2. Lift up the positive jump post protective cover on the vehicle to be jumped and attach the positive lead of the jumper cable.
3. Locate the large hex shaped negative grounding lug on the shock tower or firewall on the vehicle to be jumped, and attach the negative lead (black) of the jumper cables to the grounding lug.

CAUTION

Be very careful to keep the jumper cables away from moving parts (cooling fan, belts, etc.) on both engines.

1. Connect the negative lead to the supply vehicle's battery ground, or to a suitable chassis or engine ground. DO NOT allow the jumper cable leads to touch one another at any time.
2. Once the vehicle has been started, turn on the headlights and set the climate control blower to the highest speed for at least 10 seconds before disconnecting the battery jumper cables to avoid a voltage spike at the voltage regulator.
3. Carefully disconnect the cables in the reverse order of connection. Start with the negative cable that is attached to the engine ground, then the negative cable on the donor battery. Disconnect the positive cable from the donor battery and finally, disconnect the positive cable from the formerly dead battery. Be careful when disconnecting the cables from the positive terminals not to allow the alligator clips to touch any metal on either vehicle or a short and sparks will occur.

Jump Starting Precautions

Be sure that both batteries are of the same voltage. Most vehicles on the road today use a 12-volt charging system.

Be sure that both batteries are of the same polarity (have the same terminal, in most cases NEGATIVE grounded).

Be sure that the vehicles are not touching or a short could occur.

On serviceable batteries, be sure the vent cap holes are not obstructed.

Do not smoke or allow sparks anywhere near the batteries.

In cold weather, make sure the battery electrolyte is not frozen. This can occur more readily in a battery that has been in a state of discharge.

Do not allow electrolyte to contact your skin or clothing.

---------

For more car related problem troubleshooting:---

This are the sections, you can go through and click the link to read its troubleshooting.

---------

The car will not start?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-start.html

-----------------

Car will not crank?

http://schematicsdiagram.blogspot.com/2011/06/car-will-not-crank.html

-----------

Car has no spark?

http://schematicsdiagram.blogspot.com/2011/06/car-has-no-spark.html

-------------

How to troubleshoot car battery?

http://schematicsdiagram.blogspot.com/2011/06/how-to-troubleshoot-car-battery.html

-----------------

How to test starter solenoid?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-starter-solenoid.html

--------------------

How to test cars starter?

http://schematicsdiagram.blogspot.com/2011/06/how-to-test-cars-starter.html

How to replace starter in car?

http://schematicsdiagram.blogspot.com/2011/06/how-to-replace-starter-in-car.html

-----------

car will turn over but will not start?

http://technoanswers.blogspot.com/2011/05/car-will-turn-over-but-will-not-start.html

-----------------

Car wont start?

http://howtobyme.blogspot.com/2011/10/car-wont-start.html

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