Haltech E6A - Manual (Page 118)

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E.3 Synchronisation Events
Synchronisation Events (Sync Events) are required for sequential and direct fire systems. The
Sync Event gives the ECU in indication of the engines position. The most common form of
Sync Event is a Home Trigger. Other Sync Events are the missing teeth on multitooth triggers.
A Home Trigger is usually a separate trigger from the main trigger, but some special trigger
sensors, such as the Haltech Hall Effect Sensor, can generate both signals from the one sensor.
For a direct fire system the home trigger tells the ECU that the next trigger is for coil one
(which is usually connected to cylinder one). The ECU then cycles through its ignition outputs
until it expects a Home trigger again. If it receives a Home it will cycle again. If it does not
receive a Home before the next trigger, it will not output a spark until the Home is received.
Home triggers for the E6A do not need to be accurately timed. All it does is tell the ECU that
the next main trigger is significant. Usually, but not necessarily, the significance is that the next
main trigger is for cylinder one. Therefore, the Home trigger must occur before the main
trigger for cylinder one and after the main trigger preceding the cylinder one trigger. (See
figure 6 over the page). The Home trigger should not occur at the same time as any other
trigger. Check that the trigger and Home Edges are set correctly.
Figure 6. Home Trigger position on cam angle sensor for 4 cylinder with a home trigger
every cam revolution.