Note. The following procedure only applies to models with the F8Q engine. On F9Q engines, fast idling is controlled by the electronic injection module and no further adjustments are required.
Vacuum drive and cable
Removing
1. The vacuum drive is mounted on a bracket mounted on the end of the fuel pump.
2. Loosen the screw or nut and remove the lug from the cable on the fast idle lever on the fuel pump.
3. Disconnect the vacuum hose from the drive.
4a. Fast idle vacuum drive 1 - Bosch pump.
4b. Fast idle vacuum actuator 1 - Lucas pump.
5. Remove the nut securing the drive to the bracket and remove the drive by passing the cable through the bracket (refer to illustrations).
Installation
1. Install the drive on the bracket and tighten the fixing nut.
2. Connect the vacuum hose.
3. Insert the cable through the fast idle lever and place the lug on the cable, but do not tighten the screw or nut yet.
4. Adjust the cable as described in the following paragraphs.
Checking and adjusting - Bosch fuel pump
1. Proceed as described in Section 9 and following the note at the beginning, the distance between the edge of the fast idle lever and the tip should be 2±1 mm.
2. If a vacuum actuator failure is suspected, first check the solenoid assembly as described later in this Section.
3. The drive can be checked with a vacuum pump. (Engine must be off), disconnect the vacuum hose from the actuator and attach a vacuum pump to it. At a pressure of 500 mbar, the actuator must move the cable so that the lever touches the fast idle adjustment screw. If this is not the case, the vacuum actuator is probably defective.
Checking and Adjusting - Lucas Fuel Pump
1. The fast idle speed is factory set on the test stand and cannot be adjusted.
2. With the engine stopped and with the fast idle lever in its original position, carefully insert the fast idle cable.
3. Place the tip on the cable so that the distance between the edge of the fast idle lever and the tip is 2±1 mm.
4. With the tip correctly positioned, tighten the nut.
5. The drive can be checked by referring to the paragraphs in Section Removing, installing, checking and adjusting the thermal actuator and fast idle cable, but note that the fast idle lever must touch the stopper, not the fast idle adjustment screw.
Solenoid valve
Removing
1. On F8Q 620 engines, the solenoid valve is located on the bulkhead in the engine compartment, next to the preheat control unit. On F8Q engines with a turbocharger, it is located in the engine compartment on the upper A-pillar.
2. Disconnect the wiring and disconnect the vacuum hoses from the solenoid valve.
3. Loosen the two fixing screws and remove the valve.
Installation
1. Install in reverse order. Make sure vacuum hoses and electrical wiring are securely connected. Tighten the screws.
Examination
1. Remove the solenoid valve as described above.
2. Try to blow air through one of the vacuum hose connections. Air must not pass through the valve.
3. Plug in the power (12V) to the valve winding terminals and try again to blow air through the valve. Now the air should pass.
4. If the valve does not work as described, it should be replaced.