Air Supply System

Check for excess intake air entering the engineCIS.023

  1. Check Hoses and Boots Check carefully for leaks:
    • Hoses and clamps for auxiliary air regulator.
    • Boots, ducts and clamps connecting air flow sensor to throttle valve.
    • PCV hoses, clamps.
    • Vacuum hoses, clamps, reservoirs.
  2. Check the Air Sensor
    • The air sensor plate is lifted from the air cone during starting and running.
    • The air sensor plate height should be checked with the engine off, warm, and with residual fuel pressure still in the system (within 10 minutes after shut off)
    • The sensor plate should be even with the bottom rim of the air cone at the edge nearest the fuel distributor.
      • To adjust bend spring clip up or down.
    • The sensor plate should also be centered in the air cone.
      • To center loosen sensor plate bolt.CIS.024
  3.  Check Vacuum Advance and Retard
    • With the engine idling remove the vacuum retard hose – idle speed should increase if the vacuum retard is working.
      • Reconnect the vacuum retard hose.
      • Increase engine speed to 3000 RPM, remove vacuum advance hose – engine speed should decrease if vacuum advance is working.
      • Reconnect vacuum advance hose.
  4. Check EGR Valve
    • The EGR valve must be closed during starting and idling.
    • With engine idling, connect a vacuum pump and apply vacuum:
      • Valve should open
      • Engine speed should decrease
    • Release vacuum:
      • Valve should close
      • Engine speed should increase to normal
  5. Check Injector Seals And Inserts
    • Remove injectors and check injector seals and inserts.
    • Check injector seals carefully for damage or looseness.
    • Check that the injector inserts are tight with 12mm hex wrench.
    • If inserts are loose:
      • Remove inserts
      • Clean threads
      • Apply Loctite T with Loctite 620 (or equivalent).
      • Torque inserts to 22Nm (16 ft.lbs.)
      • Check injectors before installing (see following page)