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Volkswagen Workshop Service and Repair Manuals

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Servicing injection pump > < Servicing injectors

Golf Mk3

Diesel Injection and Glow Plug System
Servicing fuel injection system
Checking injector nozzle valve tip for damage, injection pressure and for leakage.

Checking injector nozzle valve tip for damage

(Visual check)

If the injector pin is damaged, e.g. broken or bent, replace the injector nozzle or the needle in the nozzle body.
 
V02-0184

→ Checking opening pressure

Warning!
When testing injectors ensure that the jet of fuel does not contact the hands as the high pressure will cause the fuel to penetrate the skin and may cause severe injuries.

Engine code AAZ

  • ● Pressure gauge on
  • ‒ Move pump lever down slowly. When spray begins, read off opening pressure. For deviations from specification renew injector.
         Specification:
         new injectors: 150 ... 158 bar
         Wear limit: 140 bar

Engine code 1Y

  • ● Pressure gauge on
  • ‒ Move pump lever down slowly. When spray begins, read off opening pressure and, if necessary, correct by replacing the shim.
    Specification: (excess pressure)
         new injectors: 130 ... 138 bar
         wear limit: 120 bar

Note:

When servicing used injectors adjust breaking pressures to specifications for new injectors.

  • ◆ Thicker shims increase breaking pressure.
  • ◆ Thinner shims decrease breaking pressure.
  • ◆ Increasing spring compression by 0.5 mm increases breaking pressure by 5.0 bar

Adjustment shims are available from 1.00...1.95 mm thick and increase by 0.5 mm. Use box 3065 to store shims.

Checking for leaks

  • ● Pressure gauge on
  • ‒ Move pump lever down slowly and maintain a pressure of approx. 110 bar for 10 seconds. No fuel should leak from the nozzle tip.

Servicing injection pump > < Servicing injectors