Haltech E8 - Manual (Page 158)

Haltech E11/E8 Instruction Manual
more information on S3 and S4 Hall effect trigger systems.
Multi-Tooth Trigger
These triggers are typically found on Toyota, Honda and Mazda rotary engines.
The ECU is capable of triggering from multi-tooth pickups, as used on a number of production vehicles.
The ECU employs software signal conditioning to convert the multi-tooth trigger to standard form. This is
done by counting teeth from a “synchronisation event” (or Home signal), until a certain tooth is reached
which corresponds to the engine location specified as the Trigger Angle. The ECU then performs ignition
and possibly injection in the same fashion as the standard trigger.
After recognising the synchronisation event, the ECU will locate the first “standard” engine trigger by the
tooth indicated as Tooth Offset in the Ignition Set-up page. To find the remaining “standard” engine
triggers, the ECU counts a number of teeth equal to the total teeth in one CAM revolution, divided by the
number of cylinders.
For Example a 4-cylinder engine with a 24-tooth wheel on the cam and a corresponding home would have
the following setup values:
Trigger Angle: 65° (10° to 90° as required)
Trigger Type: Multi-tooth
Total Teeth: 24
Tooth Offset: 2 (1 to Total Teeth)
With these setup values, when the Home signal occurs the ECU will start counting the trigger teeth (24-
tooth wheel), when it reaches the tooth offset it will operate as a standard trigger. The position of the
remaining triggers is determined by taking the number of teeth in the trigger wheel (24) divided by the
number of cylinders (4). This number (6) is the number of teeth that is counted between triggers.
In this case the triggers will occur at the following teeth: 2,8,14,20. Each trigger occurs 65° (Trigger
Angle) BTDC of the current cylinder and will perform ignition based on this angle.
Nissan Trigger
The Nissan optical trigger sensor is used by almost every ECU controlled Nissan engine. It is a sensor
that spins at half the engine speed, and is therefore able to measure the engine cycle position. It can be
used as a trigger for direct fire and sequential injection applications. The sensor consists of two signals
that will from now on be referred to as home and trigger.
The trigger signal consists of 360 evenly spaced pulses, where each falling edge represents 2 degrees of
engine movement.
The home signal consists of the same number of pulses as the engine has cylinders, so on a 4 cylinder
there are 4 pulses, and on a 6 cylinder there are 6 pulses. The rising (leading) edge of each slot is evenly
spaced, but the falling (trailing) edge is not evenly spaced. The differing pulse widths enables the ECU to
determine which pulse occurs immediately before cylinder number 1, the ECU does this by counting the
number of 360 pulses that occur during the trigger pulse.
There are 3 common patterns for Nissan triggers, but for each pattern, there is always a unique window.
You do not need to know what the patterns are, but you need to know which unique window size to use for
a given sensor. The sizes are described by the number of small teeth that it inside of the window of the
large slots. The following styles of Nissan sensor have been recognised:
Pattern 1 – The unique slot sizes are of pattern 8,2,2,2 for a 4-cylinder engine. Typically these are found
on early generation Nissan motors such as FJ20, RB30ET.
Pattern 2 – The unique slot sizes form pairs with two unique slots at opposite ends. Typical patterns are
4,8,12,8 for a 4-cylinder motor. For 6-cylinder motors of this pattern type, typical patterns are
4,8,12,16,12,8. These patterns are typically found in CA18 and RB20 motors.
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