Lynx L4-116 1.9L VIN J FI HP (1986)
Idle Speed: All Technical Service Bulletins
Engine - Idle Speed Fluctuation
Article No. 86-7-13
IDLE SPEED FLUCTUATION - 1.9L EFI
FORD 1986 ESCORT, EXP
LINCOLN-MERCURY 1986 LYNX
Idle speed fluctuation will occur when the throttle plate is set too low, causing the throttle air bypass valve to operate at a higher duty cycle. The ISC
actuator is more sensitive to vacuum variations at the higher duty cycle
resulting in air flow fluctuations. The combination of air/fuel flow variations cause engine speed fluctuation.
Verify proper installation of vacuum lines and the tube between the air meter and the throttle body. (Adaptive fuel attempts to "learn" to compensate for
leaks.) Set the "Throttle Plate Adjustment" to the 900 rpm decal specification with the cooling fan turned on (800 rpm for vehicles with less than 100
miles). Refer to adjustment procedure.
"Relearning" the adaptive fuel cells near idle will improve idle stability. This is best accomplished by running the vehicle in neutral, with the throttle air
bypass valve electrically disconnected, at each of the following conditions for approximately one minute: 900 rpm - no load, 900 rpm - full load (A/C,
headlights, heater fan), 1200 rpm - no load, and 1200 rpm - full load.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: 9500C
TIME:
0.3 Hr. DLR. CODING: Basic Part No. 9510 - Code: N4
