Base Idle Speed
CURB IDLE SPEED1. Confirm initial inspection conditions:
a. Engine coolant temperature is 185 - 205°F.
b. Lights, cooling fan and all accessories are OFF.
c. Transaxle is in neutral or park.
d. Steering wheel is in straight-ahead position, (on vehicles with power steering).
2. Check the ignition timing and adjust, if necessary (refer to the procedure).
Tachometer Connection:
3. Connect the pick-up lead of a tachometer to the connector.
4. Start the engine and operate at 2500 rpm for more than 5 seconds and then at idle for 2 minutes.
5. Check the engine idle speed. If it is NOT within specifications, check the idle speed control system.
Curb Idle Speed:
750 ± 100 RPM
6. Stop engine and disconnect tachometer (if further adjustments are required, do not disconnect the meter).
Ignition Timing Adjustment Hook-up:
IDLE SPEED CONTROL (ISC) SYSTEM
1. Remove the protective cap from the ignition timing adjustment connector.
2. Using a suitable jumper, connect the terminal to ground.
Idle Speed Adjustment Jumper Wire:
3. Using a suitable jumper wire, ground the #10 terminal in the self-diagnosis connector.
4. Start the engine and warm to operating temperature and check the idle speed.
Basic Idle Speed:
750 ± 100 RPM
5. If necessary, adjust to the specified speed by turning the speed adjusting screw.
NOTE
- The engine speed may be slightly lower on a new engine (less than 300 miles) in which case, no adjustment is required.
- If the engine speed is low, there is a possibility of carbon deposits on the throttle valves assembly.
- If the idle speed is too high and normal adjustments do not bring the speed within range, there is a possibility that the fast - idle air valve has an internal leak. If so, this will require replacement of the throttle chamber.