Idle Speed - New Setting Procedure

85ford19

Article No. 85-19-7

IDLE SPEEDS - 1.9L - NEW IDLE SPEED SETTING PROCEDURE

FORD 1985-86 ESCORT

LINCOLN-MERCURY 1985-86 LYNX

CALIBRATION: All Altitude with 2V Carburetor

WARNING: This service is authorized only for the listed engines. Performing this service on other engine calibrations is unauthorized and could create liability under applicable federal or local laws.

On new vehicles (in altitude areas only) and on customer complaint vehicles, it is recommended the idle speed including full stroke be checked and reset to specification per the procedure listed in the 1985-86 Engine Emission Diagnosis Manual, Volume H.

NOTE: The 1.9L 2V ISC speed setting procedure is different from the prior 1.6L procedure due to design changes. The correct procedure must be followed to obtain satisfactory speed settings for the various conditions and accessory loads.

Instructions

1. Place the transmission in Neutral or Park, and the A/C-Heater selector in the Off position.

2. Bring engine to normal operating temperature.

3. Ensure that engine timing is to specification. Refer to Section 15.

4. Disconnect and plug vacuum hose at thermactor air control valve bypass section.

Figure 4 - MECHANICAL VACUUM IDLE SPEED CONTROL (ISC) - CURB IDLE RPM 1.9L ENGINE WITH 740-2V:

5. Place the fast idle adjusting screw on the second step of the fast idle cam (Figure 4). Run engine until cooling fan comes on.
6. Slightly depress throttle. Engine cooling fan must be on to allow fast idle cam to rotate. Place ATX transmission in Drive. Check and compare curb idle rpm to specification.

If adjustment is required:

^ Place transmission in Park (ATX) or Neutral (MTX), deactivate the ISC by removing the vacuum hose at the ISC and plugging the hose.

Figure 4 - MECHANICAL VACUUM IDLE SPEED CONTROL (ISC) - CURB IDLE RPM 1.9L ENGINE WITH 740-2V:

^ If full stroke rpm is not to decal specification, adjust rpm by turning the full stroke speed adjusting screw (Figure 4).

^ Connect a vacuum pump, 021-00014, to the ISC and supply sufficient vacuum to retract ISC plunger clear of the full stroke speed adjusting screw (Figure 4).

^ Place the transmission in Drive (ATX) or Neutral (MTX), if throttle stop rpm is not to decal specification (fan on), adjust rpm by turning the throttle stop adjusting screws (Figure 4).

At this point you may check and adjust the dashpot.

^ Engine Off and the ISC plunger retracted, (clear off the adjusting screw).

^ Depress the dashpot plunger into the dashpot assembly.

^ Measure the distance between the throttle lever pad and the dashpot plunger. Adjust to decal specification by loosening the dashpot locking nut and turning the dashpot assembly (Figure 4). Tighten the locking nut.
^ Restart engine; bring it to operating temperature with cooling fan on.

^ Place the transmission in Park (ATX) or Neutral (MTX), remove vacuum pump from ISC, remove plug from ISC vacuum line and reconnect to ISC.

Figure 4 - MECHANICAL VACUUM IDLE SPEED CONTROL (ISC) - CURB IDLE RPM 1.9L ENGINE WITH 740-2V:

^ Place the transmission in Drive (ATX) or Neutral (MTX), if ISC curb idle rpm is not to decal specification (fan on), adjust by turning the ISC curb idle adjusting screw (Figure 4).
NOTE: Plug must be removed from back of unit. Reinstall plug after adjustment is made.

7. Place transmission in Neutral or Park. Rev the engine momentarily. Place transmission in specified position and recheck curb idle rpm. Readjust if required.

8. Remove plug from thermactor air control valve bypass section hose and reconnect.
9. If the vehicle is equipped with an automatic transmission and the curb idle adjustment was out of specification more than 50 rpm, refer to automatic transmission linkage adjustment procedure, Group 17, Powertrain Manual.

OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY"