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Home >> Volvo >> 1983 >> 245 GLT, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - BOSCH LH >> Testing >> System Function Check >> System Check
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System Check

  1. Connect a voltmeter to one of the injectors. Peel back the rubber cover from around one of the injectors. Connect the positive lead (red lead) of a voltmeter to the Yellow/Red wire and the negative lead to the Green/White wire. Set meter to read 0-4 volts.
  2. Check the start function. Remove connectors from all injectors so that engine does not start. Remove connector from temperature sensor to simulate cold start.
  3. Crank engine and check meter deflection. Deflection should be large when first cranking and then decrease. Connect temperature sensor. Crank engine. Voltmeter should deflect as before but with decreased deflection. Connect injector.
  4. Check the enrichment during warm-up. Start engine and observe meter as engine warms up to operating temperature. If enrichment function is working properly, meter deflection should decrease slightly as engine warms up. Turn ignition off. Connect rev counter. Start engine.
  5. Check idle speed, should be 12 r/s (750 rpm). Turn on air conditioning. Idle speed should increase to 15.0 r/s (900 rpm). Disengage air conditioning. If engine speed does not increase, check air control valve operation does not stick. Replace and test with new air control valve. If engine does not idle check air mass meter (step 7 & 8) below.
  6. To check fast idle function, remove connector from temperature sensor (simulates cold engine). Engine speed should increase to 1600-2500 RPM. Connect temperature sensor, engine speed should return to normal idle.
  7. Slowly increase engine speed. Voltmeter deflection should increase with engine speed. If not, check voltage signal from air mass meter.
  8. Turn off ignition. Peel back rubber cover from air mass meter connector. Connect voltmeter positive lead to terminal 7 and negative lead to terminal 6. Start engine. Voltage should increase as engine speed increases. Replace and test with new control unit if air mass meter is OK.
  9. With voltmeter still connected to injector, check acceleration enrichment. Quickly increase engine speed. Meter deflection should at first be large and then reduce slightly.
  10. To check fuel shut-off during engine braking, increase engine speed to 2000 RPM. Quickly release throttle control. Meter deflection should go down to 0 until speed reduces to approximately 1400 RPM. At 1400 RPM, meter should show deflection again.
  11. To check full throttle enrichment, unplug connector from throttle valve switch. Engine speed will increase slightly. Increase engine speed to at least 3500 RPM. Connect a jumper wire between connector terminals 18 and 3. Meter deflection should increase slightly (enrichment). Reconnect throttle valve switch.
  12. Turn off engine. Remove voltmeter from the injector. Reposition rubber connector cover.
  13. To check air mass meter measuring wire dirt burn-off, peel back boot from air mass meter connector. Connect a voltmeter to terminals 8 (+) and 36 (-). Start engine and increase engine speed to over 2000 RPM. Turn off ignition. After approximately 5 seconds voltmeter should show approximately 1 volt for 1 second.
  14. Remove voltmeter. Reposition rubber boots around air mass meter and injector wiring connectors.
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