MoTeC M8 - Manual (Page 19)

MoTeC Installation 17
Engine Temp Sensor
The Engine Temperature sensor is mainly used for cold start enrichment.
The sensor contains a temperature dependant resistor and is designed for
water immersion.
The ECU Sensor Setup parameters must be set to indicate the particular type
of sensor.
Trigger Sensors (REF & SYNC)
The trigger sensors supply the necessary timing information to the ECU so
that it knows when to fire the fuel injectors and ignition system. Generally two
sensors are used, REF and SYNC.
Many different types of trigger sensors and chopper patterns may be used.
The wiring and ECU setup information for the trigger sensors are specific to
the particular system. Refer to the appropriate MoTeC drawing.
Home made sensor systems often cause problems. Do not use Chrome molly
for chopper disks as it is a non magnetic material. Runout of the disk,
imperfections and boltheads are also potential sources of problems. Where
possible it is best to use the manufacturers trigger system.
REF Sensor
Supplies the crank position information.
Some sensors supply one pulse per Top Dead Centre (4 pulses per engine
rev on a V8), others supply as many as 360 pulses per engine rev.
The Engine RPM is derived directly from this signal.
SYNC Sensor
Used to indicate each engine cycle, which is required for sequential injection
and multi coil operation.
Generally supplies one pulse per engine cycle (2 revs on a 4 stroke engine).
On some special trigger systems the ECU can be synchronised using the
REF sensor only (eg. Ford Narrow Tooth)
REF / SYNC Alignment
Most modern distributors supply both REF and SYNC signals in which case
the alignment is preset.