Fuel Injector Timing and Duration

PURPOSE
The Engine Control Module (ECM) contains memories for the basic discharge durations at various engine speeds and manifold pressures. The basic discharge duration, after being read out from the memory, is further modified by signals sent from various sensors to obtain the final discharge duration.



ADDITIONAL FUEL INJECTOR CONTROL
During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at speeds over 1,100 rpm.

Fuel cut-off action also takes place when engine speed exceeds 6,500 rpm regardless of the position of the throttle valve to prevent the engine from over-revving.



When the engine is started, the ECM provides a rich mixture by increasing fuel injector duration. Additional air is introduced into the intake manifold to raise idle speed for smooth operation after start.