These cars use a rather complex electronic fuel injection system which is controlled by a series of temperature, altitude (for California) and air flow sensors which feed information into a central control unit. The control unit then relays an electronic signal to the injector nozzle at each cylinder, which allows a predetermined amount of fuel into the combustion chamber. To adjust the mixture controls on these units requires a CO meter and several special Datsun/Nissan tools. Therefore, we will confine ourselves to idle speed adjustment.
This procedure covers idle speed only.
- Start the engine and run it until the water temperature indicator points to the middle of the temperature gauge. It might be quicker to take a short spin down the road and back.
- Open the engine hood. Run the engine at about 2,000 rpm for a few minutes with the transmission in Neutral and all accessories off. If you have not already done so, check the ignition timing and make sure it is correct. Hook up a tachometer as per the manufacturer's instructions. For automatic transmission, set the parking brake, block the wheels and set the shift selector in the Drive position.
- Run the engine at idle speed and disconnect the hose from the air induction pipe, then plug the pipe. Allow the engine to run for about a minute at idle speed.
- Check the idle against the specifications given earlier in this section. Adjust the idle speed by turning the idle speed adjusting screw, located near the air cleaner on the 200SX and the throttle chamber on the 810. Turn the screw clockwise for slower idle speed and counterclockwise for faster idle speed.
- Connect the hose and disconnect the tachometer. If idle speed increases, adjust it with the idle speed adjusting screw.