Adjusting the fuel injection system (Nissan Bluebird T12)

1. Before you begin, please refer to the warnings given in Chapters 2 and 28.

2. Place the car on a flat surface, use the handbrake, lock the wheels, select neutral gear (manual transmission) or "N" (automatic transmission).

3. Valve clearances and ignition timing must be adjusted correctly, turn off the electric cooling fan motor and all electrical consumers.

4. The idle mixture quality is adjusted at the factory, so usually only the idle speed is adjusted.

Idle speed

5. Warm up the engine to normal operating temperature.

6. Remove excess fuel from the intake manifold by revving the engine up to 2000-3000 rpm two or three times, then let it idle for one minute.

7. Check the idle speed (see Specifications). If an accurate tachometer is used, prepare the adapter shown in Figure 4.16.

8. If adjustment is required, stop the engine, disconnect the AAC valve and the throttle valve switch wiring (photo).







9. Start the engine and set the engine speed to 725 rpm by turning the idle speed adjusting screw in the IAA block (photo).





10. Stop the engine, connect the throttle valve switch and AAC valve, start the engine, remove excess fuel from the intake manifold, check the idle speed.

11. Note that the engine will not run slow enough with the AAC valve and throttle switch disconnected (500 rpm on a production car), to get the specified idle speed when they are reconnected. In this case, it will be necessary to take an empirical approach, turning the screw in half-turn increments until the correct speed is obtained.



FICD Speed - Executive

12. Prepare the vehicle and check the idle speed as described above; adjust idle speed if necessary.

13. When the base speed is correct, turn on the air conditioning system and check that the idle speed increases to the specified speed.

14. There is no adjustment. If the FICD solenoid valve is not functioning properly, check it as described in Chapter 41 and replace if necessary.

Idle mixture

15. If the mixture was adjusted due to changes in engine characteristics (increased carbon deposits, wear of cylinder bores, etc.), first adjust the idle speed, then stop the engine.

16. Note that the idle mixture is checked with a CO meter (exhaust gas analyzer). If not, you will need to see a Nissan dealer. As a last resort, use the basic installation procedure, which will allow the vehicle to be started and driven to a parking spot. The system should then be checked by a qualified mechanic using the appropriate test equipment. An accurate tachometer will also be required.

17. To check the idle mixture, first warm up the engine to normal operating temperature and check the valve clearances, ignition timing and idle speed as described above.

18. Connect the CO meter according to the manufacturer's instructions, check the CO level at idle speed. If adjustment is required, proceed as follows.

19. Locate the plug in the 'corner' of the air flow meter, closest to the throttle body (notice that there are two plugs, one at the top and one at the bottom). Carefully drill a hole in the plug, then screw in the self-tapping screw and remove the plug by the screw with pliers (photo).







20. Clean excess fuel from the intake manifold (see point 6 above), then turn the idle mixture adjusting screw until the correct CO level is obtained. Recheck the idle speed, adjust if necessary.

21. Stop the engine and insert the new plug into place. Disconnect the test equipment.

22. To set the idle mixture without a CO meter, first connect an accurate tachometer and prepare the car as described in step 17 above.

23. Stop the engine, remove the plug from the air flow meter as described in point 19 above. Disconnect the wiring of the AAC valve and the throttle switch.

24. Start the engine, clear excess fuel from the intake manifold (see point 6 above), then set the idle mode.



25. Turn the idle mixture adjusting screw smoothly in each direction until the fastest idle speed is obtained, then turn the screw one turn counterclockwise in one motion.

26. The idle speed should now be 750±50 rpm. If adjustment is required, turn the idle speed adjusting screw (see point 9 above).

27. Stop the engine and reconnect the throttle switch and the AAC valve, then start the engine and check that the idle speed returns to the specified normal value.

28. Do not install a new plug until you have checked the mixture using a CO meter.

Dashpot

29. See the relevant part Chapters 41 (photo).



Throttle switch

30. The switch must be installed so that the idle contacts open at a frequency of 1050±200 rpm.

31. Adjust the installation position of the switch as described in the relevant section Chapters 41.

32. When checking the switch (ignition off) notice that it has several contacts (clamps 24 and 30), which should only open when the throttle is fully open. Replace the switch if it is faulty.