Volkswagen Workshop Service and Repair Manuals

Servicing ignition part=>Repair group 28

Notes:

• ◆ Fuel hoses in engine compartment must only be secured with spring type clips. The use of clamp or screw type clips is not permissible.
• ◆ The control unit for the fuel injection and ignition system is equipped with a fault memory. Before carrying out repairs, adjustment work and fault finding the fault memory must be interrogated and the vacuum connections checked (outside air).
• ◆ Components marked with * are checked via the self diagnosis.
  , interrogating and erasing fault memory
• ◆ Components marked with ** are checked via the final control control diagnosis => Page 01-12 .
• ◆ For trouble-free operation of the electrical components a voltage of at least 11.5 V is necessary.
• ◆ Do not use sealants containing silicone. Particles of silicone drawn into the engine, will not be burnt in the engine and damage the Lambda probe.

Safety precautions

Rules for cleanliness => Page 24-24

Technical data => Page 24-25

Self diagnosis and electrical check of the injection and ignition system => Repair group 01

Checking intake system for leaks (unmetered air) => Page 24-54

•      I -     Removing and installing air cleaner and air flow meter
  => Page 24-7
•      II -     Removing and installing throttle valve housing and idling stabilization valve
  => Page 24-10
•      III -     Removing and installing fuel manifold and intake manifold => Page 24-16
•      IV -     Removing and installing control unit, Lambda probe and coolant temperature sender => Page 24-19

Removing and installing air cleaner and air flow meter

•      A -     => Page 24-16

• Filter element
• Air cleaner upper part
• CO Potentiometer (G74)*
• ◆ Checking resistance
  , Test step 10
• ◆ The resistance is altered with the CO adjustment screw during idling adjustment
• O ring
• ◆ Renew if damaged
• CO Adjustment screw
• ◆ Idling speed check
  

• Plug
• Air ducting
• 5 Nm
• Seal
• ◆ Renew if damaged
• Connector
• Air mass meter*
• ◆ With sender for intake air temperature (G42) and potentiometer (G19)
• ◆ After renewing:
  Match Digifant control unit to engine by completing idling check
  => Page 24-26
• Metal plug
• ◆ Do not pull out

• Intake hose
• Hose
• ◆ To exhaust manifold
• Temperature regulator
• ◆ For intake air preheating
• ◆ Installation position: brass hose connection at bottom
• ◆ Checking intake air preheating
• Vacuum unit
• ◆ Checking intake air preheating
• Retaining ring
• Packing
• Air cleaner lower part

Removing and installing throttle valve housing and idling stabilization valve

•      B -     => Page 24-16
•      C -     To activated charcoal filter cut-off valve
• ◆ => Page 24-59 , vacuum hose connection diagram
•      D -     => Page 24-16

• Intake hose

• Throttle valve housing
• ◆ Throttle valve basic setting => Page 24-56
• ◆ After basic setting:
  Match Digifant control unit to engine by completing idling check
  => Page 24-39
• ◆ After renewing:
  Match Digifant control unit to engine by completing idling check
  => Page 24-39

• O ring
• ◆ Renew if damaged
• Connector
• Throttle valve potentiometer (G69)*
• ◆ 3-pin connector for injection and ignition system
• ◆ 4-pin connector additional on vehicles with automatic gearbox to control unit for automatic gearbox (J217)
• ◆ Checking => Page 24-38
• ◆ After renewing:
  Match Digifant control unit to engine by completing idling check
  => Page 24-39

• Bolt
• ◆ Lock with paint
• Seal
• ◆ Renew
• Intake manifold
• To activated charcoal filter cut-off valve
• ◆ => Page 24-59 , vacuum hose connection diagram
• Plug
• CO take-off pipe
• 10 Nm
• Plug
• For air conditioner
• To brake servo

• Bracket
• ◆ For vacuum booster
• Vacuum booster
• ◆ On vehicles with automatic gearbox
• M6 = 10 Nm
  M8 = 20 Nm
• Temperature switch
• ◆ For fan run-on, to cool the injectors
• ◆ Checking:

=> Repair Group 19; removing and installing parts of cooling system; checking radiator fan run-on

• Support bracket
• Idling speed stabilization valve (N71)**
• ◆ Checking idling stabilization
  
• ◆ Resistance: 2...10 ω

• 20 Nm
• Bracket
• ◆ For throttle closing damper
• Throttle closing damper
• ◆ Only on vehicles with manual gearbox
• ◆ Checking and adjusting
  
• Idling adjustment screw
• ◆ Idling check
  

Removing and installing fuel manifold and intake manifold

•      A -     => Page 24-7
•      B -     => Page 24-10
•      D -     => Page 24-10

• Connecting hose
• ◆ To crankcase breather
• Crankcase breather pressure regulating valve
• Bracket
• Warm air collector plate
• 25 Nm
• 20 Nm

• Return hose
• ◆ Blue or blue markings
• ◆ Secure with spring-type clips
• Retaining clip
• Supply hose
• ◆ Black or white markings
• ◆ Secure with spring-type clips
• O ring
• ◆ Renew if damaged
• Fuel pressure regulator
• ◆ Checking fuel pressure regulator and holding pressure => Page 24-45
• Seal
• ◆ Renew if damaged

• Fuel manifold upper part
• ◆ Removing and installing:
  => Page 24-48 , removing and installing injectors
• 10 Nm
• Injectors (N30...N33)
• ◆ Removing and installing
  => Page 24-48
• ◆ Checking => Page 24-51
• Sealing plug
• ◆ For test connection
• Fuel rail
• ◆ Removing and installing:
  => Page 24-48 , removing and installing injectors
• Intake manifold
• Seal
• ◆ Renew

Removing and installing control unit, Lambda probe and coolant temperature sender

• Connector
• ◆ Only disconnect or connect with ignition switched off
• Digifant control unit (J169)*
• ◆ For injection system, Lambda regulation, engine speed governor via fuel pump relay, ignition and self diagnosis
• ◆ After renewal:
  Match Digifant control unit to engine by completing idling check => Page 24-26
• Bracket

• Connector
• ◆ For Lambda probe and Lambda probe heating
• ◆ Check Lambda probe heating voltage supply between contacts -1- (red/white) and -2- (brown/black) with engine running:
       Specification:
       approx. battery voltage
• ◆ Check Lambda probe heating at Lambda probe connector (white wiring) for continuity
• ◆ Contact 3 - Lambda probe screening
• ◆ Contact 4 - Lambda control

• Lambda probe (G39)*, 50 Nm
• ◆ Fitting location: catalyst
• ◆ Grease only the threads with "G5"; "G5" must not get into the slots on the probe body
• ◆ Checking Lambda probe and Lambda control
  => Page 24-32
• ◆ Note various versions
  => Page 24-23 , Fig. 1
• Earth wire
• Retaining clip
• Connection
• O ring
• ◆ Renew if damaged

• Coolant temperature sender (G62)*
• ◆ With coolant temperature indicator sender (G2)
• ◆ If necessary before removing, release pressure from cooling system
• ◆ Resistance values
  => Page 01-28 , Fig. 1
• Connector
• 10 Nm

→ Fig. 1     Types of Lambda probe

•      1 -     Heated Lambda probe
• (A - drilling) for vehicles without catalyst
•      2 -     Heated Lambda probe
• (B - slot) for vehicles with catalyst