Engine - High/Erratic Idle
87ford14
Article No. IDLE - ERRATIC OR HIGH - 2.3L HSC CFI -
87-19-7 DIAGNOSTIC AND SERVICE TIPS
FORD: 1985-87 TEMPO
LINCOLN-MERCURY: 1985-87 TOPAZ
ISSUE: Erratic or high engine idle speed on 1985-87 Tempo/Topaz vehicles with 2.3L HSC CFI may be caused by incorrect setting of the throttle stop adjusting screw (hard stop), linkage or throttle body binding, TV rod adjustment, or EEC IV processor.
ACTION: To correct this, use the following service diagnostic procedure.
NOTE: Before proceeding, make sure there are NO SYSTEM VACUUM LEAKS.
1. If high idle is not present during initial check, perform EEC IV Self-Test. If Service Codes are present, refer to the Engine/Emission Diagnosis Shop Manual, Volume H, Section 16 for instructions. For 1987 vehicles (only), if Continuous Service Code 78 appears, follow Pinpoint Test Q-60. If condition is still present, continue to Step 2.
2. If learned idle is above specification make sure the throttle plate is free and cruise control cable (if equipped) is not holding the throttle open.
NOTE: Refer to the specification charts on pages 18 and 19 of this TSB for engine idle speed.
3. Check to see if the throttle lever is in contact with the idle tracking switch (ISC motor).
a. If there is contact, apply a light upward force on the throttle lever against the tip of the ISC motor. If the ISC motor now controls the throttle RPM down to the correct Adaptive/"Learned" idle speed then the throttle lever may be bent or hard stop requires adjustment. The throttle body may have to be replaced.
NOTE: Before replacing the throttle body on ATX vehicles, make sure the TV rod adjustment with Idle Speed Control (ISC-DC motor) is retracted. Refer to TSB 86-3-20.
b. If there is no contact, determine if the throttle stop adjusting screw (hard stop) is holding the throttle plate open (high RPM). If held open, the hard stop screw must be adjusted. Retract the ISC motor and reset hard stop in the exact sequence shown below.
NOTE: The hard stop setting when properly set does not in any way determine idle speed ("learned" or fast idle).
Retract the ISC Motor:
^ Shut engine Off and remove air inlet tube from throttle body. In the engine compartment, find the Self-Test connector and Self-Test input connector.
Figure 6:
^ Connect a jumper wire between the SelfTest input connector and the signal return pin on the Self-Test connector, Figure 6.
^ Turn the ignition key to the "Run" position. DO NOT START ENGINE.
^ The ISC plunger will retract. Wait until plunger is fully retracted (about 5 to 15 seconds).
NOTE: If plunger does not retract, refer to EEC IV diagnostics.
^ Return the ignition key to the "Off" position; wait 10 to 15 seconds.
^ Remove the jumper wire.
Figure 7:
^ Disconnect the ISC motor from the wire harness, Figure 7.
Perform Throttle Hard Stop Adjustment:
^ Remove throttle body from vehicle.
^ Remove the Welch plug which covers the throttle stop adjusting screw, Figure 7.
^ Remove and replace screw if loose.
^ Reinstall throttle body on vehicle, check electrical connectors, start engine, let engine stabilize, and set the idle RPM, ^ Reconnect the ISC motor to wire harness, Figure 7.
4. With engine idling, observe ISC extending to curb idle position. Check the area between the throttle lever and tip of the ISC motor. If no contact is apparent between these two surfaces, binding may exist at the throttle body. With engine Off, open throttle to Wide Open Throttle (WOT). Upon release, throttle should return to the closed position. If contact is apparent between the ITS and the throttle lever, it is possible that binding at the throttle body may be just enough to keep the ITS from operating. Determine source of binding (bent shaft, shaft seal swelling, or cruise control) and replace or repair as necessary.
5. If condition is still present, replace the EEC IV processor. Refer to the specification charts on pages 18 and 19 of this TSB. Start engine and run for at least 3 seconds and turn ignition key to the Off position. Inspect ISC motor retracting and repositioning to make sure of proper operation.
CAUTION: If for any reason the battery is disconnected or the vehicle has to be jump started, this procedure may need to be performed.
a. Set parking brake and block wheels. If equipped with automatic brake release, disconnect the vacuum hose and plug it. Make all checks/adjustments with engine at normal operating temperature and accessories Off. Only the TACH is needed for the following procedure. Before proceeding, check for vacuum leaks.
b. After transmission is engaged in Drive for ATX or Neutral for MTX, and the engine has idled for 120 seconds, idle RPM should be within specification.
c. Lightly step on and off the accelerator. The engine RPM should return to the specification stated in the charts on pages 18 and 19 of this TSB. If the RPM remains high, repeat the sequence. It may take the system an additional 120 seconds to "learn".
NOTE: "Learned" and fast idle speeds are controlled by the EEC IV processor and the idle speed control motor. If the control system is operating properly, these speeds are fixed by the processor and cannot be changed by traditional adjustment techniques (for example, hard stop screw).
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OPERATION: SP871907A - Hard stop adjust only
TIME: 1.0 Hr. DLR. CODING: Basic Part No. DRIVE - Code: L5
Processor Idle Speed Adaptive/"Learned" Air Replaced By
(12A650) (ISC Motor Idle Speed Distribution Processor
Calibration Engine Production Fully Retracted) (EEC Controlled) Plate (12A650) (3)
1985 MTX
5-25F-R0 (49S) Base E53Z-HB/HC 640 RPM in Neutral 750 RPM in Neutral Yes E63Z-VB
5-25F-R10 (49S) Base E53Z-HC/HD 640 RPM in Neutral 750 RPM in Neutral No E63Z-VB
5-25Q-R0 (Calif) Base E53Z-GB/GC 640 RPM in Neutral 750 RPM in Neutral Yes E63Z-XB
5-25Q-R10 (Calif) Base E53Z-GC/GD 640 RPM in Neutral 750 RPM in Neutral No E63Z-XB
1985 ATX
5-26E-R0 (49S) Base E53Z-DB/DC 550 RPM in Drive 600 RPM in Drive Yes E63Z-TG (1)
5-26E-R10 (49S) Base E53Z-DC/DD 550 RPM in Drive 600 RPM in Drive No E63Z-TG
5-26E-R21 (49S) Base E53Z-TE/TF 600 RPM in Drive 650 RPM in Drive No E63Z-TG
5-26J-R01 (2) (49S) Base E53Z-DB/DC 550 RPM in Drive 600 RPM in Drive Yes E63Z-TG
5-26J-R11 (2) (49S) Base E53Z-DC/DD 550 RPM in Drive 600 RPM in Drive No E63Z-TG
5-26R-R01 (Calif) Base E53Z-EB/EC 550 RPM in Drive 600 RPM in Drive Yes E63Z-UG (1)
5-26R-R11 (Calif) Base E53Z-EC/ED 550 RPM in Drive 600 RPM in Drive No E63Z-UG
5-26R-R16 (Calif) Base E63Z-UE/UF 600 RPM in Drive 650 RPM in Drive No E63Z-UG
1985-86 MTX - HIGH OUTPUT (HO)
5-25C-R01 (49S) Plus HO E53Z-KA/KB 650 RPM in Neutral 800 RPM in Neutral Yes E53Z-KB
5-25P-R0 (Calif) Plus HO E53Z-MA/MB 650 RPM in Neutral 800 RPM in Neutral Yes E53Z-MB
1986 MTX
5-25F-R10 (49S) Base E53Z-HC/HD 650 RPM in Neutral 750 RPM in Neutral No E63Z-VB
6-25F-R10 (49S) Base E63Z-VB 700 RPM in Neutral 800 RPM in Neutral No E63Z-VB (4)
5-25Q-R10 (Calif) Base E53Z-GC/GD 650 RPM in Neutral 750 RPM in Neutral No E63Z-XB
6-25Q-R10 (Calif) Base E63Z-XB 700 RPM in Neutral 800 RPM in Neutral No E63Z-XB (4)
1986 ATX
6-26E-R0 (49S) Base E63Z-TF 600 RPM in Drive 650 RPM in Drive No E63Z-TG
6-26E-R10 (49S) Base E63Z-TG (1) 600 RPM in Drive 690 RPM in Drive No E63Z-TG (4)
6-26-R10 (Calif) Base E63Z-UF 600 RPM in Drive 650 RPM in Drive No E63Z-UG
6-26-R11 (Calif) Base E63Z-UG (1) 600 RPM in Drive 690 RPM in Drive No E63Z-UG (4)
1987 MTX - BASE ENGINE
7-25F-R00 (49S) Base E73Z-FB 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-FD
7-25F-R10 (49S) Base E73Z-FC 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-FD
7-25Q-R00 (Calif) Base E73Z-HB 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-HD
7-25Q-R10 (Calif) Base E73Z-HC 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-HD
(1) For E63Z-TG and E63Z-UG processors - remove air distribution plate (if air distribution has not been removed). Reset hardstop according to new processor (see chart for new specification).
(2) Fuel Economy Package without air conditioning - 5-26J-R01 and 5-26J-R11.
(3) Replaced by Processor Column - place a modification decal where a processor has been changed. Replace the "tear tag" sticker from processor from previous location (driver side door).
(4) Replacement processor specifications.
Processor Idle Speed Adaptive/"Learned" Air Replaced By
(12A650) (ISC Motor Idle Speed Distribution Processor
Calibration Engine Production Fully Retracted) (EEC Controlled) plate (12A650) (3)
1987 MTX - HO (PLUS) ENGINE
7-25C-R00 (49S/Can) Plus HO E73Z-EA 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-EC
7-25C-R10 (49S/Can) Plus HO E73Z-EB 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-EC (4)
7-25P-R00 (Calif) Plus HO E73Z-GA 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-GC
7-25P-R10 (Calif) Plus HO E73Z-GB 700 RPM in Neutral 850 RPM in Neutral Yes E73Z-GC (4)
1987 ATX - HO (PLUS) ENGINE
7-26D-R00 (49S) Plus HO E73Z-JA 600 RPM in Drive 690 RPM in Drive Yes E73Z-JB
7-26T-R00 (Calif) Plus HO E73Z-NA 600 RPM in Drive 690 RPM in Drive Yes E73Z-NB
1987 ATX - BASE ENGINE
7-26E-R00 (49S) Base E73Z-KA 600 RPM in Drive 690 RPM in Drive Yes E73Z-KC
7-26E-R10 (49S) Base E73Z-KB 600 RPM in Drive 690 RPM in Drive Yes E73Z-KC (4)
7-26R-R00 (Calif) Base E73Z-KA 600 RPM in Drive 690 RPM in Drive Yes E73Z-KC
7-26R-R10 (Calif) Base E73Z-KB 600 RPM in Drive 690 RPM in Drive Yes E73Z-KC (4)
(3) Replaced by Processor Column - place a modification decal where a processor has been changed. Replace the "tear tag" sticker from processor from previous location (driver side door).
(4) Replacement processor specification.