volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

Checking intake air preheating > < Checking fuel pressure regulator and holding pressure
Motronic fuel injection and ignition system ä 07.95
Motronic injection and ignition system
Checking intake air system for leaks (unmetered air)

Checking with engine leak detector spray G 001 800 A1

Special tools, testers and auxiliary items

  • ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
  • ◆ Engine leak detector spray G 001 800 A1

Notes:

  • ◆ The vacuum in the intake system will cause the leak detector spray to be drawn in with the outside air. The leak detector spray reduces the ignitability of the mixture. This leads to a drop in engine speed and to a significant increase of the CO content.
  • ◆ The safety precautions listed on the container must be adhered to.

Test sequence

  • ‒ Start engine and run at idling speed.
  • ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit (address word 01); carry out selection at idling.
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Input 08 for "Read measured value block" function and confirm with Q.
 
→ Indicated on display:
Read measured value block     HELP
Input display group number XX
  • ‒ Input 01 for display group 01 and confirm with Q.
 
→ Indicated on display:
(1...4 = Display zones)
Read measured value block 1     ⇒
     1     2     3     4

Note:

If something different is indicated on the display:

=> Fault reader operating instructions

  • ‒ Read and note Lambda probe factor in display zone 3.
  • ‒ Systematically spray parts of the intake system with engine leak detector spray.

If the engine speed drops or the Lambda factor voltage changes in display zone 3:

  • ‒ Check for leaks in the area of intake system sprayed and eliminate leak.

Checking intake air preheating > < Checking fuel pressure regulator and holding pressure