Ignition Coil: Testing and Inspection

1986-88 Trooper II & Pickup W/4ZD1 & 4ZE1 Engines
1. Check outer face of ignition coil for cracking, rusting or damage to socket area.

Fig. 2 Checking coil resistance.:

2. Check resistance of primary coil (A-C) and secondary coil (A-B) as shown in Fig. 2. Primary coil resistance should be 1.10-1.40 ohms on 1986-87 models and 0.9 ohms on 1988 models. Secondary coil resistance should be 8,600-13,000 ohms on 1986-87 models and 9,400 ohms on 1988 models.
3. If measured resistance is not as specified in step 2, replace coil assembly.

Fig. 1 Checking coil resistance.:

4. Check insulator resistance (A-body) as shown in Fig. 1. Insulation resistance should be 10 megohms or more.
5. If measured resistance is not as specified in step 4, replace coil assembly.
6. If the measured values deviates from the specified range, replace the ignition coil.