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Home >> Cadillac >> 1983 >> Cimarron Automatic >> Repair and Diagnosis >> Engine Performance >> Ignition System - 4-CYL >> Testing >> Ignition System Check >> Integrally Mounted Ignition Coil

Integrally Mounted Ignition Coil

  1. Remove a spark plug wire and attach spark tester to wire. Crank engine and check for spark at tester gap. If there is no spark, check a second wire in same manner. If sparks result, ignition system is not at fault. Suspect fuel system or spark plugs.
  2. If no spark resulted in step 1, disconnect 4-wire EST connector between distributor and ECM. Crank engine and recheck for spark at tester gap. If spark occurs with EST connector disconnected, proceed to EST System Check.
  3. If no spark occurred in step 2, with 4-wire connector disconnected, check voltage at battery terminal of ignition coil. Attach positive voltmeter lead to battery terminal of ignition coil and negative lead to ground. Check for voltage while cranking engine.
  4. If reading is less than 7-volts, repair primary circuit back to ignition switch. If 7-volts or more, move positive voltmeter lead from battery terminal to "TACH" terminal. Leave negative lead grounded.
  5. If reading is under 1 volt, ignition coil connection or ignition coil is defective. Repair or replace as necessary. If 10 volts or more is registered on voltmeter, proceed to step 7. If voltmeter reading is 1-10 volts, proceed to step 6.
  6. If voltage reading on "TACH" terminal was 1-10 volts, replace distributor HEI-EST module and check for spark, following procedure outlined in steps 7, 9, and 11. However, if a spark results in step 11, ignition system is okay following module replacement. If there is still no spark, replace ignition coil also, as it too is defective.
  7. If in step 5, 10 volts or more were read on "TACH" terminal, attach spark tester to coil output terminal (inside distributor cap) with cap still connected to distributor by wiring harness. Crank engine and check for spark.
  8. If no spark occurs, proceed to step 9. If spark occurs, check color match of pick-up coil connector and ignition coil lead (see note). Inspect cap for water, cracks or other damage. If okay, replace rotor.
    NOTE: Ignition coils with Red and White leads should be matched with pick-up coils having either a Clear, a Black, or a Blue connector. Ignition coils with Red and Yellow leads must be matched with pick-up coils with a Yellow connector.
  9. If no spark occurred in step 7, remove pick-up coil leads from module. Connect positive lead of voltmeter to coil "TACH" terminal and negative lead to ground. Turn ignition on. For no more than 5 seconds, connect test lamp from battery positive supply to HEI-EST module terminal "P". Watch voltmeter as test lamp touches terminal.
  10. If voltage drops, proceed to step 11. If voltage does not drop, check module ground screw. Also check for open in wires from distributor cap (coil) to distributor. If okay, replace HEI-EST module.
  11. If voltage dropped in step 10, check for spark at tester gap (still attached to coil output terminal) when test light is removed from module terminal. If spark occurred, either pick-up coil or its connections are defective. Perform Distributor Pick-Up Coil Short and Resistance Check if not done previously. Resistance should be 500-1500 ohms.
  12. If distributor module tester is available, check HEI-EST module. If okay, check ignition coil ground. If ground is okay, replace ignition coil. If module is defective, replace.
  13. If no module tester is available, check ignition coil ground circuit. If okay, replace ignition coil and repeat steps 7, 9, and 11. If spark results, system is okay. If no spark results, original ignition coil is okay. Reinstall original ignition coil and replace HEI-EST module.
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