Ignition Coil: Testing and Inspection

Fig. 1 Checking coil resistance.:

Exc. 1986-88 Trooper II & Pickup W/4ZD1 & 4ZE1 Engines
1. Check outer face of ignition coil for cracking, rusting or damage to socket area.
2. Check resistance of primary and secondary coil as shown in Fig. 1. Primary coil resistance should be 1.130-1.529 ohms. Secondary coil resistance should be 10,200-13,800 ohms.
3. If measured resistance is not as specified in step 2, replace coil assembly.
4. Check insulator resistance as shown in Fig. 1. Insulation resistance should be 10 megohms or more.
5. If measured resistance is not as specified in step 4 or if tester needle deflects slightly, replace coil assembly.