Volkswagen Corrado (1993 year). Manual - part 150

 

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Volkswagen Corrado (1993 year). Manual - part 150

 

 

H - TESTS W/O CODES 

         ENGINE DOES NOT START OR IS DIFFICULT TO START WHEN COLD

      *  Check for insufficient fuel in tank.
      *  Check fuel pump relay and fuel pump.
      *  Check fuel system for leaks.
      *  Check auxiliary air intake system.
      *  Check fuel system after-start, acceleration enrichment and
         warm-up circuits.
      *  Check cold-start valve.
      *  Check airflow sensor lever adjustment and control plunger.
      *  Check sensor plate rest position and idle circuit.
      *  Check fuel system differential and residual pressures.
      *  Check fuel injection volume.
      *  Check engine coolant temperature sensor.
      *  Check ignition timing, spark plugs, distributor, secondary
         ignition wiring and coil.
      *  Check Hall Effect sensor.
      *  Check ignition coil power output stage.

         ENGINE DOES NOT START OR IS DIFFICULT TO START WHEN WARM

      *  Check radiator cooling fan after-run circuit.
      *  Check fuel pump check valve.
      *  Check fuel evaporative frequency solenoid(s).
      *  Check fuel system for leaks.
      *  Check auxiliary air intake system.
      *  Check idle speed.
      *  Check fuel system after-start, acceleration enrichment and
         warm-up circuits.
      *  Check cold-start valve.
      *  Check injector fuel pressure and volume.
      *  Check sensor plate rest position and idle circuit.
      *  Check sealing ring under control plunger.
      *  Check fuel system differential and residual pressures.
      *  Check engine coolant temperature sensor.
      *  Check ignition timing, spark plugs, distributor, secondary
         ignition wiring and coil.

         UNEVEN IDLE OR NO IDLE WITH COLD ENGINE OR DURING WARM-UP

      *  Check fuel evaporative frequency solenoid(s).
      *  Check fuel system for leaks.
      *  Check auxiliary air intake system.
      *  Check idle speed.
      *  Check oxygen sensor control circuit.

H - TESTS W/O CODES 

         ENGINE STARTS BUT STALLS

      *  Check fuel pump relay and fuel pump.
      *  Check auxiliary air intake system.
      *  Check idle speed.
      *  Check fuel system after-start, acceleration enrichment and
         warm-up circuits.
      *  Check airflow sensor lever adjustment and control plunger.
      *  Check sensor plate rest position and idle circuit.
      *  Check fuel system differential and residual pressures.
      *  Check idle switch.
      *  Check engine coolant temperature sensor.

         IDLE SPEED EXCEEDS SPECIFICATION

      *  Check throttle cable adjustment.
      *  Check fuel evaporative frequency solenoid(s).
      *  Check auxiliary air intake system.
      *  Check idle speed.
      *  Check throttle potentiometer.
      *  Check idle switch.
      *  Check engine coolant temperature sensor.
      *  Check throttle body basic adjustment.
      *  Check ignition timing.

         POOR ACCELERATION WITH COLD ENGINE OR DURING WARM-UP

      *  Check fuel pump.
      *  Check auxiliary air intake system.
      *  Check oxygen sensor control circuit.
      *  Check fuel system after-start, acceleration enrichment and
         warm-up circuits.
      *  Check airflow sensor lever adjustment and control plunger.
      *  Check throttle potentiometer.
      *  Check fuel system differential and residual pressures.
      *  Check injector fuel pressure and volume.
      *  Check idle switch.
      *  Check engine coolant temperature sensor.
      *  Check throttle body basic adjustment.
      *  Check exhaust system.
      *  Check ignition timing, spark plugs, distributor, secondary
         ignition wiring and coil.

H - TESTS W/O CODES 

      *  Check fuel pump.
      *  Check auxiliary air intake system.
      *  Check injector fuel pressure and volume.
      *  Check idle and full throttle switches.
      *  Check intake air preheating system.
      *  Check ignition timing, spark plugs, distributor, secondary
         ignition wiring and coil.

         POOR PERFORMANCE

      *  Check fuel pump.
      *  Check throttle cable adjustment.
      *  Check auxiliary air intake system.
      *  Check airflow sensor lever adjustment and control plunger.
      *  Check throttle potentiometer.
      *  Check fuel system differential and residual pressures.
      *  Check injector fuel pressure and volume.
      *  Check full throttle switch.
      *  Check mass airflow sensor (if equipped).
      *  Check intake air preheating system.
      *  Check catalytic converter.
      *  Check ignition timing.

         ENGINE RUN-ON (DIESELING)

      *  Check fuel evaporative frequency solenoid(s).
      *  Check fuel system for leaks.
      *  Check cold-start valve.
      *  Check injector fuel pressure and volume.
      *  Check airflow sensor lever adjustment and control plunger.

         HIGH FUEL CONSUMPTION

      *  Check fuel system for leaks.
      *  Check oxygen sensor control circuit.
      *  Check cold-start valve.
      *  Check injector fuel pressure and volume.
      *  Check airflow sensor lever adjustment and control plunger.
      *  Check throttle potentiometer.
      *  Check injector fuel pressure and volume.
      *  Check full throttle switch.
      *  Check mass airflow sensor (if equipped).
      *  Check intake air preheating system.
      *  Check exhaust system for leaks (between cylinder and
         oxygen (O2) sensor).
      *  Check ignition timing.

         ENGINE KNOCK

      *  Check knock sensors (if equipped).

H - TESTS W/O CODES 

         ENGINE RUNS UNEVENLY OVER ENTIRE SPEED RANGE

      *  Check auxiliary air intake system.
      *  Check injector fuel pressure and volume.
      *  Check ignition timing, spark plugs, distributor, secondary
         ignition wiring and coil.

         INTERMITTENTS

         INTERMITTENT PROBLEM DIAGNOSIS

         Intermittent fault testing requires duplicating circuit or
component failure to identify the problem. These procedures may lead
to the computer setting a fault code (on some systems) which may help
in diagnosis.
         If problem vehicle does not produce fault codes, monitor
voltage or resistance values using a DVOM while attempting to
reproduce conditions causing intermittent fault. A status change on
DVOM indicates a fault has been located.
         Use a DVOM to pinpoint faults. When monitoring voltage,
ensure ignition switch is in ON position or engine is running. Ensure
ignition switch is in OFF position or negative battery cable is
disconnected when monitoring circuit resistance. Status changes on
DVOM during test procedures indicate area of fault.

         TEST PROCEDURES

         Intermittent Simulation
         To reproduce the conditions creating an intermittent fault,
use the following methods:

      *  Lightly vibrate component.
      *  Heat component.
      *  Wiggle or bend wiring harness.
      *  Spray component with water.
      *  Remove/apply vacuum source.

         Monitor circuit/component voltage or resistance while
simulating intermittent. If engine is running, monitor for self-
diagnostic codes. Use the test results to identify a faulty component
or circuit.  For system or component testing refer to the appropriate
I - SYS/COMP TESTS article in this section. See the menu below:

      *  For Cabriolet, see:  I - SYSTEM/COMPONENT TESTS
      *  For Corrado SLC, see:  I - SYSTEM/COMPONENT TESTS
      *  For EuroVan, see:  I - SYSTEM/COMPONENT TESTS
      *  For Fox, see:  I - SYSTEM/COMPONENT TESTS
      *  For Golf, GTI, Jetta, see:  I - SYSTEM/COMPONENT TESTS
      *  For Passat GL 2.0L 4-Cylinder, see:

 

 

 

 

 

 

 

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