Engine - Idle Speed High/Slow Return to Idle
87ford10Article No.
87-3-11
^ IDLE - SPEED HIGH - 2.3L OHC
^ IDLE - SLOW RETURN TO CURB IDLE - 2.3L OHC
FORD
1985-86 MUSTANG, LTD
LINCOLN-MERCURY
1985-86 CAPRI, MARQUIS
ISSUE:
A higher than normal idle speed and/or slow return to curb idle may be caused by the Keep Alive Memory (KAM) being erased because of a power disruption.
(Example: EEC processor replacement or battery disconnect.) This may cause the EEC strategy to seek an initial throttle position sensor value that is beyond the adaptive learning range for curb idle speed. No service codes will be displayed in self-test to help diagnose the above conditions.
ACTION:
To correct this, perform the following service diagnostic procedure.
1. Disconnect the cruise control cable sleeve (if so equipped).
2. Check/adjust closed plate (Kill Speed) adjustment per revised TSB # 87311 - Idle Speed Setting Procedure.
3. Reconnect ISC motor after reset.
4. Reconnect cruise control and adjust (if so equipped).
CAUTION:
^ Do not use KOEO Self-Test to retract ISC motor.
^ Do not shut off and restart engine with ISC disconnected.
^ Do not do a "clean out" (throttle movement) during this procedure.
Any of the above actions will put the system into a L.O.S. (Limited Operation Strategy) mode, causing air to be dumped and timing to be fixed at 10~ BTDC.
NOTE:
If the system goes into L.O.S., repeat the above corrective action (noting the stated cautions).
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS:
Reimbursable within the provisions of the Warranty and Policy Manual
OPERATION: SP870311 A - Includes Quick Test
TIME: 0.8 Hr. DLR. CODING: Basic Part No. DRIVE - Code: M5
Idle Speed Setting Procedures
PASSENGER CAR - 50 STATES AND CANADA
2.3L (OHC) Engine w/YFA-1V FB, DC Motor Idle Speed Control (ISC) - Curb Idle Speed and Fast Idle Speed Checks/Adjustments
Instructions
If curb idle is not within specification after performing this procedure, it will be necessary to perform the appropriate 2.3L OHC FBC EEC-IV diagnostic procedure.
1. Preliminary Procedure
a. Block wheels, apply parking brake and bring engine to normal operating temperature.
b. Remove air cleaner, disconnect and plug vacuum line at bottom of air cleaner.
c. Turn off all accessories.
Note: After adjustments are completed, reconnect all parts.
2. Closed Throttle Plate Speed Adjustment (Kill Speed)
a. Simultaneously hold throttle open to maintain 1000 RPM while pressing lightly on the ISC motor shaft.
b. After shaft retracts completely, release throttle and quickly unplug ISC motor connector.
c. If electric cooling fan comes on during kill speed, set procedure, disconnect power lead and proceed.
d. Check closed plate RPM (700 +/- 25 RPM) while in Neutral.
e. If adjustment is required, remove tamper resistant cap using pliers/screwdrivers. Adjust RPMs to specification by turning throttle plate stop screw, (Fig. 1).
Caution: Do not shut engine off or actuate throttle. Doing so will put the EEC-IV system into L.O.S. strategy mode, causing incorrect adjustments.
3. Idle Speed (Cannot be adjusted - EEC-IV controlled)
a. All accessories off.
b. Verify engine idle speed as specified on emission decal.
c. If speed is not within specification, refer to the 2.3L OHC EEC-IV diagnostic procedure.
d. If the idle speed is revised per the diagnostic procedure, the bowl vent set must be checked and adjusted if necessary, as specified below:
^ Allow engine to run at curb idle with transmission in position specified on decal.
^ Disconnect ISC electrical connector, engine should remain at curb idle RPM.
^ Turn engine off, throttle position will not change.