System Testing

Checking For Battery Voltage At Coil:

1. Visually check all spark plug cables and spark plugs for proper installation or damage.
2. Check for proper installation of primary ignition coil wire at coil terminals and at ballast resistor.
3. If above checks are satisfactory, check and record battery voltage.
4. Disconnect coil secondary lead from distributor cap. Turn ignition On, then momentarily ground negative terminal of coil using suitable jumper wire while holding coil secondary lead 1/4 inch from good ground. If no spark is observed, turn ignition Off, then disconnect four-wire electrical connector at electronic control unit. If spark is observed, proceed to step 10.

NOTE: Before connecting or disconnecting the harness connector from the control unit, check to ensure that the ignition switch is in the Off position.

5. Repeat step 4. If spark is observed, replace electronic control unit.
6. If no spark is observed, measure voltage at coil positive terminal. Reading obtained should be within one volt of previously recorded battery voltage.
7. If voltage reading is zero, replace starter relay and check wiring between battery positive terminal and coil, see figure.
8. If voltage reading obtained in step 6 is not continuous, replace ignition resistor and repeat step 6.

Checking For Battery Voltage At Coil-Negative:

9. Check battery voltage at coil negative terminal, see figure. Reading obtained should be within one volt of battery voltage. If voltage reading is satisfactory, but no spark is observed when coil negative terminal is grounded, replace coil.

Checking For Battery Voltage At Cavity No. 2:

10. If spark was obtained in step 4 or step 9, but engine will not start, disconnect four-wire connector from electronic control unit (if not previously removed), then with ignition On, check for battery voltage at cavity 2 of ECU harness connector. Reading obtained should be within one volt of battery voltage, see figure.

Checking For Continuity:

11. If voltage reading is not satisfactory, turn ignition Off, and check for continuity between cavity 2 and coil negative terminal using suitable ohmmeter, see figure. If continuity is not present, check for damaged wiring or loose connections and repair as necessary.

Checking For Continuity:

12. If voltage reading in step 10 is satisfactory, check for battery voltage at cavity 2 of ECU connector. If battery voltage is not obtained, turn ignition Off and check for continuity between cavity 1 and ignition switch using suitable ohmmeter, see figure. If continuity is not present, check for damaged wiring or loose connections and repair as necessary.

Checking For Resistance:

13. If battery voltage is obtained at cavity 2 of ECU connector, turn ignition Off and check resistance between cavities 4 and 5 of ECU harness connector using suitable ohmmeter, see figure. Reading of 150-900 ohms should be obtained.
14. If reading is satisfactory, check wiring between cavities 4 and 5 for open or short circuit and repair as necessary. If wiring is satisfactory, check for proper operation of dual pick up start-run relay.

Checking For Resistance In Pick Up Coil:

15. If ohmmeter reading obtained in step 13 is not between 150-900 ohms, disconnect pick up leads and measure resistance at distributor side of pick up lead, see figure. If reading obtained is not between 150-900 ohms, replace pick up coils as necessary.

Checking For Short Circuit At Pick Up:

16. Check for short circuit at each distributor side of pick up lead by connecting ohmmeter as indicated in see figure. If ohmmeter indicates pick up is shorted, replace pick up coil.
17. pick up coil is satisfactory, check for proper ECU ground contact by connecting ohmmeter between pin 5 of ECU and ground. If ohmmeter indicates poor ECU ground contact, check for proper ECU installation or poor ECU electrical connections.
18. If ECU is properly grounded, reconnect all electrical connections and check again for spark. If no spark is available, replace ECU.