FSE Fuel Pressure Valve

On a Fuel injected car the fuel is held at pressure behind the injectors to produce the spurt of fuel into the chambers when the injector opens. Now the fuel pump is running all the time and hopefully can produce more fuel than the engine requires (You have a problem if it doesn't). So there is a return pipe that send the excess fuel back to the tank. The Fuel pressure valve is the valve that sets the fuel pressure at the rail and allows the excess to return. The standard valve is set in pressure (nominally 3.2 bar in the Zetec 2.0L).

If you modify the engine for power it will require more fuel to release that energy. This means the injectors will open for longer to allow more fuel to flow. If the fuel requirements exceed the speed at which the fuel pump can replenish the plenum or more like likely the pressure in the plenum drops and alters the flow then you may loose power and develop flat spots.

Below is my FSE valve, note the adjustment knob on top and the Omex twin coil adapter sitting behind it (yellow wires to coil, blue to unit)

This is what happened to me after I fitted the K&N filter. There are 2 solutions to this

1.    Up rate the fuel pump so it can provide more fuel faster

2.    Increase the pressure in the fuel plenum so there is a greater reserve (also the injectors squirt more fuel in a shorter time)

As you have probably realised by now the FSE fuel Pressure valve tackles the last solution

The kit that comes contains all that you need to remove the old Ford valve and fit the adjustable valve. It mounts external to the engine block and the kit contains the blanking plates you need.

A warning: Ford uses a Fuel line that is lined by plastic. It will not fit over the FSE valve fittings that assume normal fuel line. I replaced the Ford lines with new heavy gauge fuel line.

Fitting the valve immediately removed the flat spots so it works as advertised. It will not produce any more power but but may allow more fuel in quicker and hence enhance performance. Itg can certainly allow you to burn more fuel quicker if required, but will not increase fuel consumption normally as the same amount of fuel is being used.

Drawbacks: I have noticed 2 problems with the valve

1. Fuel pressure tends to creep up with time (1 year), the FSE is supposed to raise the pressure by 150% roughly i.e. around 5 bar), but mine had drifted up to 6 bar at the end of the year resulting in the second problem
2. The increased back pressure strains the plenum area. My old 100k jets were dribbling fuel even when closed (giving high emissions), resetting the fuel pressure to 4 bar cleared this up and did not result in flat spots. I would advise anyone to slowly turn down the Fuel pressure until the problems come back and then raise it just enough to get rid of the flat spot

So, mine works and does what it says, but has to be used with caution