1271 to 1276 - Ignition Coil

Component Location:

Preparation
1. Remove the fuel injector sound insulation.
2. Remove the cylinder head sound insulation.

Direct Ignition Component Locations:

3. Disconnect the coil electrical connector.

Ignition Coil Connector:

Checking the Coil
4. Measure the resistance between terminal 1 and terminal 15 of the ignition coil.

^ Resistance should be 0.45 ohms (+10%). Replace as necessary.

5. Measure the resistance between terminal 2 of coil electrical connector and ground. Refer to Diagrams Electrical for connector identification

^ Resistance should be approx. 240 ohms. If not check circuit for opens.

6. With the ignition (ON) test for voltage at terminal 3 of the ignition coil electrical connector.

^ Reading should be 12 volts. If not check circuit between terminal 3 of the ignition coil and terminal 15 of the ignition switch for open or short. Repair as necessary.

7. While cranking the engine test for pulsating ground signal at terminal 1 of the ignition coil electrical connector.

^ Reading should alternate between 0 and infinite resistance to ground. If not check the circuits to the final output stages of the Digital Motor Electronic (DME) control unit. If the circuits are OK refer to Computers and Control Systems for testing the DME control unit.

CAUTION: Be sure to use a Digital Volt Ohm Meter (DVOM) or other special tool suitable for this purpose. Do not use test lights with incandescent bulbs for testing computer controlled circuits, ECM damage may result.

Do-It-Yourself LED Test Light:

Shop Made LED Test Light: A simple test light may be constructed from normally available components.

8. Check cast material of coil carrier for hairline cracks or burning. Gray material running out at the edges of the coil carrier is indicative of a faulty ignition final stage in the DME control unit. Replace as necessary.