Haltech S4 Hall Effect Sensor - Manual (Page 8)

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 a
re 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 sys tem 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 E6K do not need to be accurately timed. All it does is tell the
ECU that the next main trigger is significant. Usually, but not n
ecessarily, 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). 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 a cam angle sensor for 4 cylinder with a home trigger
occurring every cam revolution.