Pinpoint Test D: Low Pressure Fuel Line Pressure Tests

WARNING: This page is about a different car, the 2019 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

D1: LOW PRESSURE FUEL LINE PRESSURE TEST 1

WARNING: This procedure involves fuel handling. Be prepared for fuel spillage at all times and always observe fuel handling precautions. Failure to follow these instructions may result in personal injury

NOTE: This procedure involves disconnection of fuel lines. Place suitable absorbent material around the fuel line to be disconnected, to absorb any spillage when connecting the fuel pressure gauge.

Make sure the vehicle is in Park and apply the parking brake
Set ignition status to OFF

Disconnect the fuel supply line from the low pressure fuel pump fuel supply connection

Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC

Connect the manufacturers approved fuel pressure gauge in the fuel supply connection on top of the low pressure fuel pump flange. Remove the absorbent material and dispose of safely
Set ignition status to ON
Record the fuel pressure reading

Is the fuel pressure >4.5bar?

Yes

GO to D2.

Remove the fuel pump module flange (to allow access to the fuel lines on the underside of the fuel pump module flange. (Refer to: LOW PRESSURE FUEL PUMP ASSEMBLY (G2767407) . Inspect the low pressure fuel pump internal fuel lines for any leakage, blockage or de-latching. Inspect the in-tank fuel filter for blockage. Check if the pump pressure relief valve is jammed open or leaking, fuel pump module pressure regulating valve jammed open or leaking. Repair as required. If no fault found, GO to PINPOINT TEST F .

D2: LOW PRESSURE FUEL LINE PRESSURE TEST 2
NOTE: This procedure involves disconnection of fuel lines. Place suitable absorbent material around the fuel line to be disconnected, to absorb any spillage when connecting the fuel pressure gauge.
1. Reconnect the fuel supply line to the low pressure fuel pump fuel supply connection
2. Disconnect the low pressure fuel supply line from the fuel filter
3. Connect the manufacturers approved fuel pressure gauge in the fuel line between low pressure fuel pump and fuel filter. Remove the absorbent material and dispose of safely
4. Set ignition status to ON
5. Record the fuel pressure reading
Is the fuel pressure >4.4bar?

Yes

GO to D3.

No

Inspect low pressure fuel line between low pressure fuel pump and engine mounted fuel filter. Repair as required
D3: LOW PRESSURE FUEL LINE TEST 3
1. Disconnect the pipe which connects the fuel filter and High Pressure (HP) fuel pump from the fuel filter
2. Connect the manufacturers approved fuel pressure gauge between the fuel filter and the pipe to HP fuel pump
3. Set ignition status to ON
4. Record the fuel pressure reading
Is the fuel pressure >4.3bar?

Yes

GO to D4.

No

Faulty fuel filter. Replace fuel filter
D4: LOW PRESSURE FUEL LINE TEST 4
1. Disconnect the fuel supply pipe from the High Pressure (HP) fuel pump
2. Connect the manufacturers approved fuel pressure gauge in the fuel line between the fuel supply pipe and the HP fuel pump
3. Set ignition status to ON
4. Record the fuel pressure reading
Is the fuel pressure >4.3bar?

Yes

Check the HP fuel pump inlet for any blockage due to debris. If no fault found, GO to PINPOINT TEST E .

No

Check the fuel line between the high pressure fuel pump and fuel filter. Replace or repair fuel line as necessary and retest