Haltech E6K - Manual (Page 121)

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B.3.3 Synchronising
To be able to synchronise the injectors with the motor, the E6K needs a Synchronisation
Event, usually in the form of a ‘Home’ Trigger to operate in sequential mode. The Home
trigger is separate from the main trigger and it tells the ECU that the next injection is to be for
channel 1. Each injection is calculated from a main trigger. The first trigger after a Home
trigger calculates injection for channel 1. Each main trigger after that will sequence through
the channels in the order mentioned earlier. i.e. the order will be channels 1, 2, 5 and lastly 4
(if all four are used). If the Home trigger does not occur, however, injections will continue,
but injector synchronisation cannot be assured until the home pulse is received again.
B.4 Multi-tooth Triggers
The E6K is capable of triggering from multi-tooth pickups, as used on a number of production
vehicles. The E6K 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 E6K then performs ignition (and possibly injection) in the same
fashion as the standard trigger.
After recognising the synchronisation event, the E6K 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 E6K 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 100° 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.
Due to the high frequency of multi-tooth signals the maximum Rpm to which the ECU will
operate is 10,500 rpm.