The fuel injectors are of the slim five-hole type (pencil fuel injector) located centrally over the piston recess. The injectors are retained to the cylinder head by clamps.
The fuel injector tips are insulated from direct contact with the cylinder head by copper heat shield washers. New washers must be installed every time the injectors are removed.
The best possible mixture formation is achieved by the intake of turbulent air and a high fuel injection pressure.
Fuel Injection Pump
The Ford Focus has a Bosch VP-30 distributor type fuel injection pump. The fuel injection pump is chain driven from the crankshaft and incorporates a pump control unit located on the top of the pump.
The pump control unit receives data from the rotation angle sensor located within the fuel injection pump and the powertrain control module (PCM). The pump control unit calculates the actuation signals for the high-pressure solenoid valve and the fuel injection timing solenoid valve, in order to control the fuel delivery through the high-pressure solenoid valve.
The fuel system incorporates a feature that prevents the fuel tank running dry and consequently drawing air into the system. The first stage of run dry strategy is to illuminate the low fuel warning indicator when the fuel level in the fuel tank reaches 9% of a full tank. When the fuel level in the fuel tank reaches 4% of a full tank the engine will start to misfire and the maximum engine speed will be reduced until the engine stalls.
A new fuel injection pump may be supplied in a locked or unlocked position. This can be determined by inspecting the fuel injection pump driveshaft locking bolt. A locked fuel injection pump is fitted with a hexagon head bolt and supplied with a spacer. An unlocked fuel injection pump is fitted with an allen key bolt and no spacer. The fuel injection pump driveshaft must not be turned while locked.
The fuel system must be bled when a new fuel injection pump is installed.
New fuel injection delivery pipes must be installed if they are disconnected at either end or removed completely as correct seating cannot be guaranteed.
