System Pressure, Fuel Pressure Regulator And Residual Pressure, Checking

WARNING: This page is about a different variant/trim than selected.

NOTE:

Fuel pressure regulator is integrated in fuel filter and cannot be replaced individually.

Special tools and workshop equipment required

Hose clamps up to 25 mm dia. 3094
Fuel Inj. Pressure Gauge-CIS K-Jetronic V.A.G 1318 with adapters V.A.G 1318/11, V.A.G 1318/17 and V.A.G 1318/23

Test Conditions

Fuel Pump (FP) Relay OK.
Fuel Pump (FP) OK, checking DIAGNOSIS AND TESTING .
Fuel filter OK.
Battery voltage at least 12.5 V.

Test Sequence

Fig 1: Fuse Holder In Driver Side Instrument Panel

Courtesy of AUDI OF AMERICA, LLC

Measuring fuel pressure:

-- Pull off cover over fuse holder in left instrument panel and pull out Fuse 27 (on fuse panel C) SC27.

WARNING:

Fuel system is under pressure! Before opening system, place clean rags around the connection. Then release pressure by carefully loosening the connection.

-- Disconnect fuel supply line -2- at right rear in engine compartment, to do so pull up release button.

Fig 2: Fuel Lines

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NOTE:

Ignore -1-.

-- Disconnect fuel supply line -arrow- on fuel rail line.

Fig 3: Fuel Supply Line On Fuel Rail Line

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-- Install a fuel-resistant assisting hose on fuel rail line.

NOTE:

Use hose clamps -arrows- to secure assisting hose.

Fig 4: Connect Fuel Inj. Pressure Gauge-CIS K-Jetronic V.A.G 1318 With Adapters V.A.G 1318/11, V.A.G 1318/17 And V.A.G 1318/23

Courtesy of AUDI OF AMERICA, LLC

-- Connect Fuel Inj. Pressure Gauge-CIS K-Jetronic V.A.G 1318 with adapters V.A.G 1318/11, V.A.G 1318/17 and V.A.G 1318/23.

-- Open shut-off valve of pressure gauge set.

The lever points in the direction of flow.

-- Start engine and let run at idle.

-- Measure fuel pressure.

Specified value: Approximately 4.0 bar positive pressure

-- Switch off ignition.

If specification is not obtained:

-- Check delivery quantity of Fuel Pump (FP) DIAGNOSIS AND TESTING .

Checking seal and residual pressure:

-- Check for leaks and for residual pressure by observing pressure loss on the pressure gauge.

After 10 minutes there must be a residual pressure of at least 3.0 bar.

If residual pressure drops below 3.0 bar:

-- Start engine and let run at idle.

-- Wait until pressure has built-up, and then switch off ignition. Simultaneously close shut-off valve of pressure gauge K-Jetronic V.A.G 1318.

Fig 5: Closing Pressure Gauge Cut-Off Valve

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Lever stands perpendicular to direction of flow -arrow-.

-- Observe pressure drop on pressure gauge.

If pressure drops again:

-- Check line connections and O-rings on the fuel rail and fuel injectors for leaks.

-- Check pressure gauge for leaks.

If pressure does not drop:

-- Open shut-off valve of pressure gauge (lever in direction of flow).

-- Remove rear seat bench Removal and Installation .

-- Unclip catches -arrows- of right connector flange cover.

Fig 6: Identifying Cover From Fuel Delivery Unit

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-- Disconnect fuel return line -arrow- by pressing release button.

Fig 7: Disconnecting Fuel Return Line By Pressing Release Buttons

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-- Connect adapter piece 1318/17-1 to fuel return line.

Fig 8: Connecting V.A.G 1318/17-1 Adapter Piece To Return Line

Courtesy of AUDI OF AMERICA, LLC

-- Clamp off adapter piece using a Hose clamps up to 25 mm dia. 3094.

NOTE:

Hose clamps up to 25 mm dia. 3094 must not be placed directly on fuel line, otherwise it may be damaged.

-- Cover return line connection with a cloth.

-- Start engine and let run briefly at idle.

-- Wait until pressure has built-up, and then switch off ignition.

-- Observe pressure drop on pressure gauge.

If pressure does not drop now, check-valve of fuel pump is malfunctioning.

-- Replace fuel pump REMOVAL AND INSTALLATION .

If pressure drops again:

-- Replace fuel filter with integrated fuel pressure regulator Removal and Installation .

NOTE:

Before disconnecting pressure gauge, release pressure by opening shut-off valve. Hold a container in front of connection for this.

-- Assembly is in reverse order of disassembly, noting the following:

-- Insert Fuse 27 (on fuse panel C) SC27 again in fuel holder in left instrument panel.

-- Install rear seat bench Removal and Installation .