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Failure To Start Test

  1. Measure battery voltage. It must be at least 12.4 volts to deliver proper voltage to ignition system. Remove coil secondary wire from distributor cap and hold 1/4" from a good ground.
  2. Prepare a special jumper wire assembly. See Fig 1 . With ignition on, momentarily touch special jumper wire to ground and coil negative terminal. A spark should be obtained at secondary wire.
    Fig 1: Jumper Wire Assembly for Grounding Coil Negative Terminal
    G1237Courtesy of CHRYSLER MOTORS.
  3. If spark was obtained, proceed to step 6). If no spark resulted, turn ignition off and disconnect 10-pin harness connector from computer. See Fig 2 . Turn ignition on. Using special jumper wire, connect negative terminal momentarily to ground. Spark should be obtained.
  4. If spark was obtained, but engine will not start, computer output is shorted. Replace computer. If no spark resulted in step 3), connect positive lead of voltmeter to coil positive terminal and negative lead to a good ground. Reading should be within one volt of battery voltage. If not, check wiring between battery and coil positive terminal.
  5. If correct voltage was recorded in step 4), move voltmeter positive lead to coil negative terminal. Again, voltage should be within one volt of battery voltage. Replace ignition coil if voltage is not present or if voltage is present, but no spark results when shorting negative coil terminal with jumper wire. Reconnect 10-pin connector.
    Fig 2: Dist & Computer Harness Connectors Used in Testing ESC Sys
    G1238Courtesy of CHRYSLER MOTORS.
  6. If in step 3) the correct spark was obtained, but engine would not start, hold carburetor switch open with a thin cardboard insulator. Measure voltage between carburetor switch and ground. Reading should be within one volt of battery voltage. If so, proceed to step 10).
  7. If battery voltage was not indicated in step 4), turn ignition off and disconnect 10-pin harness connector from computer. Turn ignition on. Connect positive lead of voltmeter to cavity No. 2 of connector and negative lead to ground. Reading should be within one volt of the battery voltage.
  8. If no battery voltage is present, check wiring from battery to ignition switch to cavity No. 2. Use an ohmmeter if necessary to check continuity of wires. Correct problem and repeat step 7). If voltage was present in step 7), turn ignition off and connect ohmmeter leads to carburetor switch terminal and cavity No. 7 of 10-pin connector.
  9. If no continuity is found, check for open wire between cavity No. 7 and carburetor switch. If continuity was indicated, connect ohmmeter leads to cavity No. 10 and to a good ground. If continuity exists, replace computer, as correct power is entering computer, but not leaving it. Repeat step 6). If no continuity existed between cavity No. 10 and ground, check for an open wire.
  10. If wiring is okay reconnect 10-pin harness connector to computer. Turn ignition on and hold secondary coil wire 1/4" from a good ground. Disconnect 3-wire distributor connector from distributor. Attach jumper wire between cavities No. 2 and 3 of harness connector. A good spark should jump from coil wire to ground.
  11. If spark resulted, but engine will not start, check voltage at cavity No. 1. If within one volt of battery voltage, replace Hall Effect Pick-Up. If no spark resulted in step 10), connect ohmmeter leads between cavity No. 2 of the distributor harness connector and cavity No. 9 of 10-pin connector. Then connect leads to cavity No. 3 of distributor harness connector and cavity No. 5 of 10-pin connector.
  12. If no continuity is present, repair open wires. If continuity exists, replace computer, as power is going into computer, but not coming out. Repeat step 10).
  13. If there was no battery voltage in step 11), turn ignition off, disconnect 10-pin connector and connect ohmmeter leads to cavity No. 1 of distributor harness connector and cavity No. 3 of 10-pin connector. If no continuity exists, repair wire and repeat step 10).
  14. If continuity existed in step 13), turn ignition on and check for battery voltage with voltmeter positive lead in cavity No. 2 of 10-pin connector and negative lead in cavity No. 10. If battery voltage is present, but vehicle will not start, replace computer and repeat step 10). If no battery voltage is present, check ground wire and repeat step 10).
CAUTION: Before replacing a computer that is thought to be defective, disconnect both the 10-pin and 14-pin connectors from the computer. Visually inspect inside of both connectors to ensure cavity terminals have not been spread or damaged, preventing them from making proper contact with mating computer pins when installed. Reinstall connectors to computer.
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