How to test and replace ignition coils on BMW 325?

Ignition Coils

First refer testing instructions,if its test faulty,then go through replacing procedure for ignition coils:---

Testing

E36 Models
Except M44 Engine

Fig. Removing the coil pack cover-M42 engine shown

Fig. Coil pack cylinder assignments-M42 engine shown

1. Refer to the spark plug removal procedures in Section 1 and remove the valve cover trim cover. On M42 engines, remove the coil pack cover.
2. With the ignition OFF , disconnect the harness connector by releasing the locking bar and pulling off the connector.
3. Check the primary resistance between the two outside terminals (terminals 1 and 15) of the coil connector socket.
4. The resistance should be approximately 0.4-0.8 ohms. Replace the coil if out of specification. The secondary side of the coil cannot be checked due to the design of the coil.

M44 Engine

The M44 engine uses a combined ignition coil assembly. The coil assembly is comprised of four separate ignition coils.

1. With the ignition OFF , disconnect the harness from the ignition coil assembly by turning the knurled electrical connector counterclockwise and carefully pulling off the connector.
2. Refer to the illustration of the primary electrical connector and check the primary resistance between the terminals for each individual coil (terminals 1 and 15) as follows:
   
   
   Coil 1: Pin 1-Pin 2

   Coil 2: Pin 6-Pin 2

   Coil 3: Pin 7-Pin 2

   Coil 4: Pin 5-Pin 2
3. The resistance should be approximately 0.4-0.8 ohms. Replace the coil assembly if out of specification. The secondary side of the coil cannot be checked due to the design of the coil.

Fig. Use an ohmmeter to check the resistance between the specified pins

Fig. The terminal pins are numbered, but difficult to see. An enhanced photo really helps. Note the absence of a pin terminal 4

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Removal & Installation

E36 Models
6- Cylinder Engines

Please refer to the spark plug removal procedures in Section 1 for details pertaining to individual ignition coil removal.

M42 Engines

1. With the ignition OFF , remove the ignition coil cover.
2. Label the wiring to ensure proper reassembly.
3. Detach the harness connector by releasing the locking bar and pulling off the connector.
4. Remove the high tension wires from the ignition coil(s).
5. Remove the ignition coil mounting fasteners, then remove the coils.
6. Installation is the reverse of the removal procedure.

M44 Engines

The M44 engine uses a combined ignition coil assembly. The coil assembly is comprised of four separate ignition coils and is replaced as a unit.

1. With the ignition OFF , disconnect the harness from the ignition coil assembly by turning the knurled electrical connector counterclockwise and carefully pulling off the connector.
2. Remove the ignition coil bracket mounting fasteners and remove the combined coil assembly.
3. Remove the combined coil cover.
4. Remove the high tension wires from the ignition coil(s).
5. Installation is the reverse of the removal procedure.

Fig. The wiring harness is removed by turning the electrical connector lock-ring counterclockwise

Fig. Once the combined ignition coil cover is removed, the high tension wires can be disconnected

Fig. Make sure to label the plug wires before removal

Fig. Clean the grounding contact and mounting bracket of the coil pack with a wire brush before installing

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For more car related problem troubleshooting:---

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

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The car will not start?

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

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Car will not crank?

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

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Car has no spark?

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

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How to troubleshoot car battery?

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

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How to test starter solenoid?

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

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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

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car will turn over but will not start?

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

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Car wont start?

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

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