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Fuel Pressure Test

  1. Release fuel line pressure. See FUEL PRESSURE RELEASE  . Remove fuse No. 17 (15-amp) from fuse holder. Connect remote control (VW 1348/3A) using adapter lead (VW 1348/3-2) and adapter cables from (VW 1594) between fuse No. 17, terminal 2 and battery positive (+) terminal. Vehicles with A/C, connect clip to remote starter aid connection in engine compartment. See Figure .
  2. Disconnect vacuum hose from fuel pressure regulator.
  3. Place a cloth under and around area where fuel gauge will be connected to fuel line to catch residual fuel.
  4. Connect pressure gauge (VW 1318) into fuel supply line between (A) Fuel supply line from tank and (B) Fuel line to fuel rail. Use adapters (VW 1318/7 and VW 1318/15). Pressure gauge shut-off valve must be in the "OPEN" position (lever in direction of flow). See Fig 1 .
    Fig 1: Identifying Installation Of Fuel Pressure Gauge & Adapters
    G00177383Courtesy of AUDI OF AMERICA, INC.
  5. Activate remote control briefly. Fuel Pump (FP) should operate. If fuel escapes during the following pressure check out vacuum connection at the fuel pressure regulator, replace the regulator.
  6. If fuel pump does NOT operate: Check fuel pump. See FUEL PUMP  .
    7. NOTE: If NO fuel pressure has built up, check whether fuel hoses (i.e. supply and return) have been transposed.
  7. Activate remote control, until pressure no longer increases. See FUEL PRESSURE SPECIFICATIONS  table.
  8. If specified value is NOT obtained: Check fuel pump. See FUEL PUMP FEED RATE  under FUEL VOLUME CHECK .
  9. Check fuel supply line for leaks or damage, such as pinching along vehicle body routing. Repair as necessary.
  10. If specified value is still NOT obtained: Replace fuel pressure regulator and repeat pressure check. If specified value is exceeded: Check return line for damage, such as pinching along vehicle body routing. Repair as necessary.
    11. WARNING: Excessive fuel pressure may create risk of explosion, rupture the fuel pressure regulator diaphragm and cause fuel to enter engine via fuel pressure regulator vacuum hose.
  11. If specified value is exceeded: Check return line for damage, such as pinching along vehicle body routing. Repair as necessary.
  12. Disconnect remote control and install fuse No. 17. To test fuel pressure regulator. See FUEL PRESSURE REGULATOR  . If testing is completed, remove fuel pressure gauge and any shop towel from engine compartment. Connect vacuum hose to fuel pressure regulator.
FUEL PRESSURE SPECIFICATIONS

Application psi (kg/cm 2 )
Engine Off
Activating Fuel Pump Circuit With Remote Control 58-61 (3.9-4.2)
Immediately After Fuel Pump Circuit De-energized 49-54 (3.3-3.7)
Residual Fuel Pressure (1)
Cold Engine 36 (0.17)
Warm Engine 41 (0.19)
(1) Measured 10 minutes after engine shut down.
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