Residual Pressure, Checking

Test sequence

-- Watch pressure drop on gauge. After 10 minutes pressure must not drop below a 4.0 bar decrease.

If pressure drops below 4.0 bar:

-- Operate Hand held remote starter (jumper) while doing this, observe display of pressure tester.

Fuel pressure must increase up to a maximum pressure of 6 bar.

-- Release control button of Hand held remote starter (jumper) and immediately close shut-off valve of pressure tester. Then lever the points perpendicular to flow direction -arrow-.

Fig 1: Closing Pressure Gauge Cut-Off Valve

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

NOTE:

When releasing control button of Hand held remote starter (jumper), fuel pressure decreases to approx. 5.6 bar.

If pressure drops below 4.0 bar again:

(Leak on fuel tank side)

-- Check connections to fuel tank for leaks.

If no malfunction can be found:

-- Check fuel filter for leaks.

-- Check fuel line to sensor flange for leaks.

-- Check all additional fuel lines in fuel tank for leaks.

If no malfunctions are found on fuel line:

-- Pressure relief valve in fuel delivery unit flange faulty.

-- Replace sensor flange which contains the pressure relief valve.

Delivery Rate, Checking

-- Remove high pressure in fuel system.

WARNING:

Fuel supply line is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully loosening the union nut.

-- Connect Pressure Gauge with adapter, as shown.

-- However, do not connect ends of Hose to fuel rail connector.

-- Hold end of Hose in a measuring container.

Fig 2: Connecting Pressure Tester VAG 1318 With Adapter VAG 1318/7, Adapter VAG 1318/10 And Adapter VAG 1318/13

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Open shut-off valve of pressure gauge. The lever points in direction of flow.

-- Switch ignition on.

-- Operate Hand held remote starter (jumper). Slowly close shut-off tap, until pressure gauge shows 4 bar fuel pressure. From this point on do not move position of shut-off tap.

-- Do not operate Hand held remote starter (jumper) any more.

-- Empty measuring container.

-- Operate remote control for 15 Seconds.

-- Compare quantity of fuel delivered with minimum delivery rate in diagram (cm³ /15s).

Fig 3: Delivery Rate Diagram

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

NOTE:

Voltage at fuel pump with engine stopped and pump running is approx. 2 volts less than battery voltage.

If minimum delivery rate is not attained:

-- Check fuel lines for possible restrictions (kinks) or blockages.

If lines are OK:

-- Replace fuel filter.

-- Repeat test.

If specified value is again not obtained:

-- Fuel Pump (FP) faulty, replace fuel delivery unit.

If delivery rate has been attained but specified value is intermittent:

-- Check Fuel Pump (FP) current draw. Refer to FUEL PUMP, CHECKING .