California

NOTE: On engines equipped with an Idle Speed Control (ISC) motor, idle speed is controlled by an electrical signal from the Electronic Control Module (ECM). Do not use the ISC plunger to adjust curb idle. The motor varies idle speed from a base (minimum authority) to a high (maximum authority) idle speed. Do not adjust unless diagnosis indicates a malfunction. Check for proper base and high idle speed as follows.

CAUTION: DO NOT disconnect or connect ISC connector with ignition "ON" as damage to the ECM may occur.

1. Perform preliminary procedures:
- Check and adjust ignition timing.
- Disconnect and plug vacuum lines for evaporative purge and EGR valve.
2. Before starting engine, place transmission in "PARK" (automatic) or "NEUTRAL" (manual), set parking brake and block drive wheels.
3. Connect dwell meter to Mixture Control (M/C) solenoid dwell lead. This is a green connection breaking out of the main wiring harness leading to carburetor.

NOTE: Remember to set dwell meter on the six cylinder scale, regardless of the engine being tested.

4. Turn A/C "OFF".
5. Start engine and run until stabilized and in "closed loop" mode (dwell meter needle starts to vary).
6. Turn ignition "OFF".

CAUTION: Do not unplug ISC connector with ignition "ON" as damage to motor will occur.

7. Unplug connector from ISC motor.



8. Fully retract ISC plunger by applying 12 volts to terminal "C" ad grounding lead to terminal "D" of the ISC motor connection.

CAUTION: DO NOT leave battery voltage applied to motor longer than necessary to retract ISC plunger. Prolonged contact will damage motor. Also, NEVER connect voltage source across terminal "A" and "B" as damage to the internal throttle contact switch will result.

9. Start engine and run until dwell meter needle starts to vary, indicating "closed loop" operation.
10. Place automatic transmission in "DRIVE".



11. With ISC plunger fully retracted, adjust carburetor base (slow idle stop screw to 470 RPM (minimum authority).
12. Place transmission in "PARK" (automatic transmissions).
13. Fully extend ISC plunger by applying 12 volts to terminal "D" and grounding lead to terminal "C" of the ISC motor connection. Leave power applied only long enough to extend the plunger.
14. MANUAL TRANSMISSIONS: Using tool J29607 or BT-8022 or equivalent, turn ISC plunger to obtain 900 RPM (Maximum Authority).
15. AUTOMATIC TRANSMISSIONS:
- With transmission in "PARK", using tool J-29607, BT-8022 or equivalent, preset ISC plunger to obtain 1500 RPM.
- With parking brake set and drive wheels blocked, place transmission in "DRIVE". Turn ISC plunger to obtain 900 RPM (Maximum Authority).
16. Recheck ISC "Maximum Authority" RPM with voltage applied to ISC motor (step 13). Motor will ratchet at full extension with power applied.



17. After adjustment of ISC plunger, measure distance from back side of plunger head to ISC nosepiece. Dimension "B" must not exceed that shown in below chart.



18. Fully retract ISC plunger (step 8). Place transmission in "PARK" (automatic) or "NEUTRAL" (manual) and turn ignition "OFF". Disconnect 12 volt power source, ground lead, tachometer and dwell meters. With ignition "OFF" reconnect four terminal harness connector to ISC motor.
19. "TRICKING" the ISC motor as described will cause the "CHECK ENGINE" light to come on and an ISC motor trouble code to be set. By restoring the system to normal operation, the light will go out, but the trouble code will continue to be stored as an "INTERMITTENT" problem. In this case, it will be necessary to clear the diagnostic trouble codes by removing the ECM fuse from the fuse block for about 10 seconds.