Adjustment
1. The engine must be turned off. Press the throttle lever fully and insert a 5 mm thick feeler gauge between the lever and the maximum engine speed stop screw on the fuel pump (see illustration).
4.1. Adjusting the after-heating switch: A - 5 mm feeler gauge; B - Maximum speed locking screw.
2. Adjust the position of the microswitch by loosening the two mounting screws and pushing it to the left. The microswitch should cut off power to the solenoid valve when the throttle lever is 5mm from the screw.
Examination
3. There is a simple method to check the operation of the microswitch. First, connect the wiring connector.
4. With the engine idling, disconnect and reconnect the EGR solenoid valve vacuum line three or four times. A noise should be heard indicating that the valve is correctly positioned.
5. The engine is still idling. Disconnect the vacuum tube again and place a small piece of paper on the connecting pipe (see illustration).
4.5. Connecting pipe (B) of the electromagnetic valve of exhaust gas recirculation.
The paper must be held by a vacuum. Then press the gas lever. The paper should fall when the throttle lever is 5mm from the maximum engine speed screw, indicating that the vacuum supply is being cut off.
6. After completing these checks, repair the electrical and vacuum connections, then test drive the vehicle at high speed (in 3rd or 4th gear), to clear the pipes.
Removal
7. Disconnect the wiring connector, unscrew the two mounting screws and remove the microswitch from the bracket on the fuel pump.
Installation
8. Install in reverse order. Adjust the microswitch as described above and tighten the mounting screws.