303-04A Fuel Charging And Controls- 4.0L: Description And Operation (page 3 of 3)

 
Each fuel rail maintains a constant fuel pressure of 4.5bar (65 psi) and is attached to each cylinder head with two bolts. 
Three fuel injectors are installed in each cylinder head and connected to the fuel rail. 'O' ring seals are used to seal the 
injectors in both the fuel rails and cylinder heads. A quick release coupling connects the feed pipe from the fuel tank to the 
fuel rail via the fuel jump hose. 
 
A flange with two threaded holes on the rear of the LH and RH fuel rails provide attachment for the fuel supply pipe. The 
fuel supply pipe has two metal-flanged ends, which locate on the fuel rail. A seal prevents leakage and each flange is 
secured with two bolts. 
 
A fuel pressure regulator is attached to the front end of the RH fuel rail and a Schraeder valve is installed in the front end 
of the LH fuel rail to provide a pressure test connection for maintenance. 
 

INJECTORS 

Six injectors are held between the fuel rails and each cylinder head. The injectors are sealed to the fuel rail and cylinder 
head by 'O' ring seals, which should be renewed whenever an injector is refitted to an engine. A small amount of engine 
oil can be applied to the 'O' rings to aid installation. No other form of lubrication should be used. Each injector sits on an 
insert that also needs to be renewed each time an injector is replaced. 
 
Each injector contains a solenoid-operated needle valve, which is closed while the solenoid winding is de-energised. The 
solenoid winding is connected to a power feed from the main relay and to an earth through the ECM. The ECM switches 
the earth to control the opening and closing of the needle valve. While the needle valve is open, fuel is sprayed into the 
cylinder inlet tract onto the back of the inlet valves. The ECM meters the amount of fuel injected by adjusting the time that 
the needle valve is open. For additional information, refer to   

Electronic Engine Controls

 (303-14A Electronic Engine 

Controls - 4.0L) 
 
 

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Injectors (6 of)