System Pressure Test

1. Fuel pressure gauge and valve (VW 1318/5) installed between fuel distributor test port (1) and cold-start valve supply line (2, removed from cold-start valve). Gauge valve is open in position and closed in position B.

Fig. 1 Fuel Pump Relay Bypass:

2. Remove fuel pump relay, and install a jumper wire with in-line switch, Fig. 1.
3. Disconnect the plug from the differential pressure regulator.
4. With the gauge valve open, activate the fuel pump and read the pressure. System pressure should be 5.2 - 5.6 bar (75 - 82 psi).

5. If pressure is below the specified value:
a. Test output quantity of fuel pump, (see "FUEL PUMP").
b. If fuel pump output is OK, replace pressure regulator.

6. If the fuel pressure is greater than specified:
a. Disconnect fuel tank return line from pressure regulator.
b. Activate the fuel pump and read the fuel pressure. (Only a slight seepage should occur at the open return line). System pressure should be 5.2 - 5.6 bar (75 - 82 psi).
c. If the pressure is OK, check for blocked fuel return line.
d. If pressure is still incorrect, replace the pressure regulator.

NOTE: System pressure is not adjustable.