Ignition Coil: Testing and Inspection

Fig. 14 Electrical Circuit Check Points:

Electrical circuit check points

1. Connect the test lamp between the coil positive terminal and ground. If test lamp does not light up, check feed to coil.
2. Connect the test lamp between the coil negative terminal and ground. If the test lamp does not light up, There are two possible failures:
a. The coil primary circuit is open.
b. The amplifier module power transistor has a dead short.

Fig. 3 Ignition coil test.:

IGNITION COIL

1. Disconnect electrical connectors and check coil continuity as shown in Fig. 3.
2. Primary circuit resistance (R1) should be .48 - .61 ohms.
3. Secondary resistance (R2) should be 9000 - 11000 ohms.
4. If readings are not as specified, test amplifier and replace as needed. If amplifier is satisfactory, ignition coil is defective.

Fig. 4 Ignition amplifier module test.:

AMPLIFIER MODULE

1. Disconnect distributor harness connector from amplifier and coil lead from distributor cap.
2. Turn ignition on and hold end of coil lead 3/8 inch from suitable ground, as far away from amplifier as possible.
3. Using suitable jumper wire momentarily apply battery voltage to terminal ``G'' of amplifier module, Fig. 4.
4. Spark should jump from coil lead to ground each time voltage is applied to amplifier module.