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Fuel pump/fuel pressure - check
Fuel and exhaust systems / Fuel pump/fuel pressure - check


Warning: Petrol is extremely flammable, so take extra precautions when you work on any part of the fuel system. Dont smoke, or allow open flames or bare light bulbs, near the work area. Dont work in a garage where a natural gas-type appliance (such as a water heater or clothes dryer) with a pilot light is present. If you spill any fuel on your skin, rinse it off immediately with soap and water. When you perform any kind of work on the fuel system, wear safety glasses, and have a Class B type fire extinguisher on hand.

Fuel pump operation check 1 Switch on the ignition and listen for the fuel pump (the sound of an electric motor running, audible from beneath the rear seats). Assuming there is sufficient fuel in the tank, the pump should start and run for approximately one or two seconds, then stop, each time the ignition is switched on. Note: If the pump runs continuously all the time the ignition is switched on, the electronic control system is running in the backup (or limp-home) mode referred to by Ford as Limited Operation Strategy (LOS).

This almost certainly indicates a fault in the ECU itself, and the vehicle should therefore be taken to a Ford dealer for a full test of the complete system, using the correct diagnostic equipment; do not waste time trying to test the system without such facilities.

2 Listen for fuel return noises from the fuel pressure regulator. It should be possible to feel the fuel pulsing in the regulator and in the feed hose from the fuel filter.

3 If the pump does not run at all, check the fuse, relay and wiring (see Chapter 6).

Fuel pressure check
3 A fuel pressure gauge, equipped with an adaptor to suit the Schrader-type valve on the fuel rail pressure test/release fitting (identifiable by its blue plastic cap, and located on the union of the fuel feed line and the fuel rail) is required for the following procedure. If the Ford special tool 29-033 is available (see Section 2), the tool can be attached to the valve, and a conventional-type pressure gauge attached to the tool.

4 If using the service tool, ensure that its tap is turned fully anti-clockwise, then attach it to the valve. Connect the pressure gauge to the service tool. If using a fuel pressure gauge with its own adaptor, connect it in accordance with its makers instructions (see illustration).

8.4 A fuel pressure gauge, equipped with an adaptor to suit the Schrader-type
8.4 A fuel pressure gauge, equipped with an adaptor to suit the Schrader-type valve on the fuel rail pressure test/release fitting, is needed to check fuel pressure

5 Start the engine and allow it to idle. Note the gauge reading as soon as the pressure stabilises, and compare it with the pressure listed in this Chapters Specifications.

(a) If the pressure is high, check for a restricted fuel return line. If the line is clear, renew the pressure regulator.

(b) If the pressure is low, pinch the fuel return line. If the pressure now goes up, renew the fuel pressure regulator. If the pressure does not increase, check the fuel feed line, the fuel pump and the fuel filter.

6 Detach the vacuum hose from the fuel pressure regulator; the pressure shown on the gauge should increase. Note the increase in pressure, and compare it with that listed in this Chapters Specifications. If the pressure increase is not as specified, check the vacuum hose and pressure regulator.

7 Reconnect the regulator vacuum hose, and switch off the engine. Verify that the fuel pressure stays at the specified level for five minutes after the engine is turned off.

8 Carefully disconnect the fuel pressure gauge. Be sure to cover the fitting with a rag before slackening it. Mop up any spilt petrol.

9 Run the engine, and check that there are no fuel leaks.


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