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Home >> Chrysler >> 1981 >> Imperial >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Combustion Control Computer >> Diagnosis & Testing >> DRIVEABILITY Checks >> Preliminary Check
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Preliminary Check

  1. Connect tachometer and adjustable timing light to engine. Start engine and allow to idle. Idle speed should be between 530-630 RPM. If not, adjust idle speed using EFI tester.
  2. Ground closed throttle switch using jumper wire. Timing light should indicate 12° BTDC. If not, adjust basic timing. Raise engine RPM to 1500 RPM with switch still grounded. If timing changes, CCC must be replaced. If timing does not change, go to next step.
  3. Remove jumper wire from closed throttle switch and decrease engine speed to 1000 RPM. Timing should be 24-30° (Federal) or 15-19° (California). If not, replace CCC. If so, go to next step.
  4. Increase engine speed to 2000 RPM. Timing should be 46-50° (Federal) or 27-31° (California). If not, replace CCC. If so, engine has passed preliminary test. Other testing must be done with EFI tester.
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