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Checking fuel pressure regulator and holding pressure > < Checking injectors

Golf Mk4

Checking injectors for leaks and quantity injected
Checking injectors for leaks and quantity injected
Test prerequisite
l  The fuel pressure must be OK, checking → Chapter.
Test procedure
–  Remove intake manifold → Chapter.
–  Now remove complete fuel rail (fuel lines remain connected) → Chapter.
Checking for leaks
–  Remove fuse holder cover.
   
–  Pull fuse No. 28 out of fuse holder.
–  Connect remote control for V.A.G 1348 -V.A.G 1348/3A- with adapter cable -V.A.G 1348/3-2- to contact 28a of fuel pump and battery positive (+).
–  Operate remote control.
If fuel pump runs:
–  Check injectors for leaks (visual check). No more than 1 to 2 drops per minute must escape from each valve when fuel pump is running.
If the fuel loss is greater:
–  Switch off ignition.
–  Replace defective injector with new one for engine codes AQP, AUE and BDE → Item, or for engine codes BFH, BJS and BML → Item
Pay attention to the following when installing the injectors:
t  Renew O-rings on all injectors and lightly moisten with clean engine oil.
t  Insert injectors vertically and in the correct position into the fuel rail and secure with retaining clips.
t  Locate fuel rail with injectors installed and secured on lower part of intake manifold and press in evenly.
Checking quantity injected
  N20-0212
–  Connect 121-pin adapter cable -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.
–  Detach injector connectors.
  N24-0943
–  For engine code BFH you must press connector catch in direction of arrow.
–  Switch on ignition.
–  Bypass sockets 2+65 of 121-pin adapter cable -V.A.G 1598/31- with test cables from auxiliary measuring set -V.A.G 1594C-. Fuel pump must start up.
  Note
This step serves only to have the fuel pump running when the engine is stopped.
–  Insert injector to be checked into measuring glass from injection rate tester -V.A.G 1602-.
  A24-0450
–  Connect a contact of injector to be tested to engine earth using auxiliary cables from auxiliary measuring set -V.A.G 1594C-.
–  Connect second injector contact with auxiliary cable to remote control for V.A.G 1348 -V.A.G 1348/3A- using adapter cable -V.A.G 1348/3-2-.
–  Connect crocodile clip to battery (+).
–  Operate remote control for V.A.G 1348 -V.A.G 1348/3A- for 30 seconds.
–  Repeat check on other injectors. Use new measuring beakers.
–  After all injectors have been activated, place measuring beakers on level surface and compare volume injected. Specification for:
AQP, AUE and BDE: 110-130 ml per valve
BFH, BJS and BML: 128-140 ml per valve
If the measured values of one or more injectors are above or below the prescribed specifications:
–  Switch off ignition.
–  Renew defective injector.
Pay attention to the following when installing the injectors:
t  Renew O-rings on all injectors and lightly moisten with clean engine oil.
t  Insert injectors vertically and in the correct position into the fuel rail and secure with retaining clips.
t  Locate fuel rail with injectors installed and secured on lower part of intake manifold and press in evenly.
  A24-0079

Checking fuel pressure regulator and holding pressure > < Checking injectors