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Checking commencement of injection valve N108 > < Checking needle lift sender G80

Polo Mk3

Checking injection timing control range
Checking injection timing control range
Special tools and workshop equipment required
t  Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with diagnosis cable -V.A.G 1551/3-
t  Adapter cable (68-pin) -V.A.G 1598/18A- or adapter -V.A.G 1598/22-
t  Hand multimeter -V.A.G 1526C- or multimeter -V.A.G 1715-
t  Auxiliary measuring set -V.A.G 1594C-
t  Current flow diagram
Engine codes AGD (with 68-pin control unit), AHG
Engine codes AGD (with 80-pin control unit), AKU → Anchor
The control range of the injection timing adjuster can be checked with the aid of the final control test and the simultaneous call-up of measured value block 04. To do this the control element for commencement of injection valve -N108- must be activated and the final control test then exited by pressing button “C”. Using this procedure the commencement of injection valve -N108- remains pulsed so that the control range of the injection timing adjuster can be read with the aid of measured value block 04 (display zone 3).
Test procedure
–  Connect fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- and select engine electronics control unit with “address word 01”. Engine must be idling. (Connecting fault reader and selecting engine electronics control unit → Chapter.)
   
Indicated on display:
–  Press buttons 0 and 3 for function “Final control diagnosis”.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
  Note
The individual control elements are activated for 30 seconds only. In the subsequent procedure you must make several entries within this period on fault reader -V.A.G 1551- and must also read off measured values. Therefore read through the subsequent steps first and become conversant with the procedures before starting tests.
–  Confirm entry with Q button.
  
Rapid data transfer                    Q
03-Final control diagnosis
Indicated on display:
–  Press the C button.
–  Press buttons 0 and 8 for function “Read measured value block” and confirm entry with Q button.
  
Final control diagnosis               ->
Commencement of injection valve N108
Indicated on display:
–  Press buttons 0, 0 and 4 for “Display group number 4” and confirm entry with Q button.
  
Read measured value block           HELP
Input display group number XXX
Appears on display
The displays in display zones 3 and 4 must fluctuate within following control range:
–  Specification in display zone 3, lower range 1° ATDC…5.0° BTDC, upper range 14.0…17.4° BTDC
–  Specification in display zone 4, lower range 2...5.0%, upper range 90...95%
The measured values which are displayed vary extensively due to the sluggishness of the fault reader -V.A.G 1551- display. Therefore, ensure that the lowest numerical value in display zone 3 lies between 1.0 and 5.0 and the highest between 14.0 and 17.4, and lowest numerical value in display zone 4 lies between 2 and 5 and the highest value between 90 and 95.
If the specifications are not achieved:
–  Press → button.
–  Press buttons 0 and 6 for function “End data transfer” and confirm entry with Q button.
–  Switch off ignition.
–  Check commencement of injection valve -N108- → Chapter.
Engine codes AGD (with 80-pin control unit), AKU
Checking the function of the injection timing control range is undertaken in function 04 (Basic settings). Using this procedure, the commencement of injection valve -N108- is pulsed so that the extreme values for advanced (early) and retarded (late) positions for the injection timing device can be read in display zone 3 of measured value block 004.
Test procedure
–  Connect fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- and select engine electronics control unit with “address word 01”. Engine must be idling. (Connect fault reader -V.A.G 1551- and select engine electronics control unit → Chapter.)
  
Read measured value block 4          ->
840 rpm   0.9° BTDC    0.9° BTDC     3%
Indicated on display:
–  Press buttons 0 and 4 for function “Initiate basic settings” and confirm entry with Q button.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press buttons 0, 0 and 4 for “Display group number 4” and confirm entry with Q button.
  
Basic setting                       HELP
Input display group number XXX
Indicated on display:
Specification in display zone 3: 6.5...9.5° BTDC
After approx. 10 seconds the timing device is moved to the retarded (late) position.
  
System in basic setting 4            ->
   861 rpm   advanced  7.9° BTDC     47%
Indicated on display:
Specification in display zone 3: 2.5...5.5° BTDC
If the specifications are not achieved:
–  Press → button.
–  Press buttons 0 and 6 for function “End data transfer” and confirm entry with Q button.
–  Switch off ignition.
–  Check commencement of injection valve -N108- → Chapter.
  
System in basic setting 4            ->
   861 rpm   retarded  4.4° BTDC     32%

Checking commencement of injection valve N108 > < Checking needle lift sender G80