18.1 Location of the various adjusting screws on the fuel pump; A Idle and fast idle lever; B Throttle lever; With clamp nipple; 1. Fast idle adjustment screw; 2. Idle adjustment screw; 3. Minimum speed limit screw; 4. Maximum speed limit screw
Idle speed check
2. Start the engine and wait until it reaches operating temperature. You can also take a short trip to warm up the engine.
3. Check idle. The engine idling speed should be within 750±50 rpm. For accurate readings, use a tachometer designed for diesel engines. If the idle speed is not correct, adjust the high pressure pump as described below.
Idle speed adjustment
4. If the idle speed readings are correct, install a 1.0 mm thick feeler gauge between the adjusting screw (3) and lever (IN) (see illustrations 18.1 and 18.4), and check if the engine speed rises by 10-20 rpm. If more increase occurs, adjust the high pressure pump as described below. If the speed increase is less than 10 rpm, adjust the idle speed as follows:
18.4 The measuring probe is installed between the throttle lever (1) and idle speed screw (2)
5. Loosen the screw locknut (3) and turn the screw to increase the speed by 10-20 rpm. Install the measuring probe as shown in illustration 18.4. Tighten the locknut again.
6. Pull out the dipstick and check that the idle speed is within the normal range.
7. Raise the engine speed several times and return to idle. Check idle speed adjustment with and without dipstick. If the value is not correct, repeat the adjustment.
High pressure fuel pump adjustment
8. If necessary, adjust the high pressure pump in the sequence shown. Be guided by illustration 18.1.
9. Remove the screw locknut (3) and turn the screw until the speed stabilizes, i.e. the engine runs at a steady but lower idle speed. From this position, turn the screw (3) two more turns.
10. Make sure the clamping nipple is above the fast idle adjusting screw (1) does not interfere with the lever (A) when moving.
11. Loosen the locknut and turn the adjusting screw (2), until the idle speed is 750 rpm. Tighten locknut and check idle.
12. Place a 1.0 mm feeler gauge between the adjusting screw (3) and lever (IN), as shown in illustration 18.4 and check that the speed has increased by 10-20 rpm. Otherwise, repeat the described adjustment.
13. Loosen the screw locknut (3) and turn the screw until the idle speed increases by 10-20 rpm, do not remove the dipstick yet. Tighten the locknut, remove the dipstick and check that the idle speed is correct.
14. Accelerate the engine, then let it idle again. Check the main idle and idle with the dipstick installed. If the data does not match, repeat the adjustment.