Engine management system - V8 (Fuel injectors): Description and operation (page 2 of 3)

There are eight fuel injectors one per cylinder that the ECM operates sequentially. All the injectors are fed from a common fuel rail as part of the returnless fuel system. Fuel pressure is maintained at a constant 3.5 bar (52 lbf.in²) by a regulator that is integral with the fuel pump. FUEL DELIVERY SYSTEM - V8, DESCRIPTION AND OPERATION, Description.

Input/Output All eight fuel injectors are supplied with battery voltage via fuse number 1 located in engine compartment fuse box. The ECM controls the individual earth path for each injector via its own pin at connector C0636 of the ECM multiplug. This facility allows the ECM to control the fuel injectors so that sequential fuel injection can take place.

Typical hot engine injector pulse width values: l Idle = 2.5 ms. l Peak torque (3000 rev/min) = 7 ms The ECM controls injector earth as follows: l Cylinder No 1 - pin 41 of connector C0636 of the ECM multiplug. l Cylinder No 2 - pin 1 of connector C0636 of the ECM multiplug. l Cylinder No 3 - pin 27 of connector C0636 of the ECM multiplug. l Cylinder No 4 - pin 40 of connector C0636 of the ECM multiplug. l Cylinder No 5 - pin 2 of connector C0636 of the ECM multiplug. l Cylinder No 6 - pin 15 of connector C0636 of the ECM multiplug. l Cylinder No 7 - pin 14 of connector C0636 of the ECM multiplug. l Cylinder No 8 - pin 28 of connector C0636 of the ECM multiplug.

Individual injectors can be measured for resistance using a multimeter. An acceptable injector resistance is as follows: l 14.5 ± 0.7 ohms at 20 °C (68 °F).

The fuel injectors can fail in the following ways or supply incorrect signal: l Injector actuator open circuit. l Short circuit to vehicle supply. l Short circuit to vehicle earth. l Blocked injector. l Restricted injector. l Low fuel pressure.

In the event of fuel injector signal failure any of the following symptoms may be observed: l Rough running. l Difficult starting. l Engine misfire. l Possible catalyst damage. l High emissions. l Adaptive fuelling disabled. l Adaptive idle speed control disabled.

The ECM performs three types of fuel injector diagnostic check: l Output short circuit to earth l Output short circuit to battery voltage l Output open circuit

Should a malfunction of the component occur the following fault codes may be evident and can be retrieved by TestBook: