Fuel Injectors
Before working on any high voltage fuel injection system, be aware of the following procedures:
- Do not make contact with the fuel injection harness, engine control module (ECM) or fuel injectors while the ignition is ON or RUN positions.
- Wait 5 minutes after key OFF to allow the electronic control module (ECM) to discharge before attempting to disconnect or test engine control components.
- Do not use the electronic control module (ECM) case as a ground while jump starting.
Failure to follow the procedure exactly as written may result in serious injury or death.
The fuel injectors are located above each cylinder and deliver fuel directly into the cylinder. Each injector has a high pressure fuel pipe from the fuel rail and a return line.
The engine control module (ECM) supplies a high voltage supply circuit and a high voltage control circuit for each fuel injector. The injector high voltage supply circuit and the high voltage control circuit are both controlled by the ECM. The ECM energizes each fuel injector by grounding the control circuit and supplying each fuel injector with up to 250 V and 20 amps on the voltage supply circuit to activate the Piezo type fuel injectors. This is controlled by boost capacitors in the ECM. During the 250 V boost phase, the capacitor is used to charge the injector piezo stack, allowing for injector opening. The injector is then held open with this high voltage. At the end of the injection event the ECM closes the injector by discharging the injector piezo stack.