Leak Test On High-Pressure Side

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Information

Check that the tool fittings are clean before starting the leak test.
Blow out the tool fittings before assembly using gentle bursts of pressure to prevent dust and foreign bodies from getting into the high-pressure system during the leak test.
Ensure that the tools for the leak test remain clean and free of dirt when stored.

Tools:

Fig 1: Identifying Leak Test Tool

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Air-spring strut - filling unit VAS 6231 WE 1282
Commercially available pressure gauge (pressure reducer) fitted on filling unit.
Adapter no. 7 from tool set K-Jetronic Tester VAG. 1318 WE 1291
Adapter no. 14 from K-Jetronic Tester VAG. 1318 WE 1291
O-ring (e.g. 8.3 x 3.05 O-ring from 997 Turbo fuel injector, part number 999.707.573.40)
Short connecting line no. 17 from tool set K-Jetronic Tester VAG. 1318 WE 1291

Information

The use of unapproved test gases results in incorrect test results. Only approved test gases guarantee comparability with fuel high-pressure systems at pressures of up to 10 bar .

Materials:

MATERIALS SPECIFICATION

Test medium	Designation	Composition/purity
Helium He (gaseous, compressed)	4.6 (minimum quality) 5.0 etc. not balloon gas	99.996 volume % (4.6) He 99.999 volume % (5.0) He
Forming gas	Forming gas 5	95% nitrogen N₂ and 5% hydrogen H₂
Leak-locating spray	e.g. TEGA test spray TPS 674	Request safety data sheet Address: Technische Gase u. Gasetechnik GmbH, Werner-von-Siemens-Strase 18, 97076 Wurzburg

WARNING: Highly inflammable or explosive materials

Danger of fire or explosion

→ Avoid contact with hot parts or sources of ignition.

→ Use suction to remove ignitable vapors.

→ Attach warning sign in a clearly visible position.

Attach warning sign in a clearly visible position on the vehicle or position in the immediate working area.

Fig 2: Example Of Warning Sign
Courtesy of PORSCHE CARS NORTH AMERICA, INC.
WARNING:
Leaking fuel supply lines
- Emerging fuel
- Risk of fire
→ Perform leak test.
Connect adapter hose to rapid-action coupling of low-pressure line -arrow- .
1. 2.1. Connect air connection of filling unit -2- to adapter -1- .
  
  Fig 3: Locating Adapter Connection In Engine Compartment
  Courtesy of PORSCHE CARS NORTH AMERICA, INC.
Fit pressure reducer -2- onto gas bottle and connect to connecting line of filling unit -3- .
1. 3.1. Check threaded connections on pressure reducer are seated securely.
2. 3.2. Check air adapter is seated securely -4- .
3. 3.3. Screw gas bottle onto screw plug -1- anti-clockwise by 2-3 turns.
  
  Fig 4: Connecting Tester
  Courtesy of PORSCHE CARS NORTH AMERICA, INC.
CAUTION:
Test pressure is exceeded
- Risk of damage to high-pressure pump
→ The test gas test pressure must not exceed a maximum pressure of 10 bar.

→ The setting is made at the pressure reducer.
Set the test pressure on the pressure reducer to between 7 and 9 bar (corresponds to a flow volume of approx. 26 - 28 liters of test gas -arrow- ).

Fig 5: Setting Test Pressure On Pressure Reducer To Between 7 And 9 Bar
Courtesy of PORSCHE CARS NORTH AMERICA, INC.
Using the test gauge -1- apply the ideal pressure to the closed fuel system.

Fig 6: Applying Ideal Pressure To Closed Fuel System Using Test Gauge
Courtesy of PORSCHE CARS NORTH AMERICA, INC.

→ Pressure: 8 bar+/-1 bar
Coat connections with commercially available leak-locating spray (see recommendation).
1. 6.1. Leaks are identifiable from bubbling and can also be heard as a hissing sound.
2. 6.2. There must be no pressure drop at the test gauge.
Leaks could be caused by a damaged sealing cone, loose connections or incorrectly fitted union nuts (damaged thread), for example.
1. 7.1. Determine causes and correct immediately.
Remove test tools.
1. 8.1. The test gases evaporate after a short time.