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| Set valve -D- to „Test“. |
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| Observe pressure gauge -C- and flow meter -E-. When the throughput quantity decreases and the pressure increases to 10 in. H2O (25 mbar), the fuel system is filled. |
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| Once pressure has stabilised, set valve -D- to „Hold“. |
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| After 5 minutes the pressure must not drop below 8 in. H2O (20 mbar). |
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| If the pressure no longer drops, renew fuel system diagnostic pump -V144-. |
| If the pressure is not held for at least 5 minutes or does not build up, localise leak as follows: |
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| Fill fuel system with smoke, set valve -D- again to „Test“ for this. |
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| While fuel system is being filled, press button -I- for smoke generator for approx. one minute. |
| The fuel system is now pressurised and filled with smoke. |
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| Check whether smoke escapes from any fuel system line or hose. Also check fuel tank cap. |
Note | t
| Light up the components and hoses with a strong floodlight. In the floodlight, smoke is more visible. |
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| For leak detection in accessible areas, also use ultrasonic detector or commercially available leak detecting spray. |
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| Depending on how long the fault finding takes, it may be necessary to press the smoke generator button from time to time. This ensures that sufficient smoke is present in the fuel system. |
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| To inspect flanges for fuel pump and fuel filter, open assembly opening in vehicle interior. |
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| Renew leaking hoses or components. |
| After completing work, perform guided function „checking fuel tank ventilation system for leaks“ using Vehicle diagnosis tester. |
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