Haltech E6X Manual DOS Version - Manual (Page 109)

E6X Manual
109
The ECU must calculate the time at which to switch the coil on to maximise energy stored in
the coil just before the spark is to occur. The coil’s charge time can be determined from the
coil negative signal: when the coil switches on, the coil negative voltage drops to zero, as the
coil energises the voltage rises slightly until a sharp rise where the ignitor current has reached
the upper limit. When the current ceases to increase the coil has maximum energy and any
more energy applied by leaving it switched on will be wasted as heat. It is at this point that
the coil is switch off and the coil is fired.
Note: For safety and reliability, always use igniters that are internally current
limited.
B.7.2 Alternate Ignition Systems
The output of the Haltech Ignition Module can be used to trigger after-market ignition
systems such as MSD or Jacobs. There are several reasons why it is not normally possible to
directly connect the ignition output of the E6X ECU to the trigger input of one of these
systems. The main reasons are lack of dwell control and the signal polarity is the inverse of
the polarity required by most of these systems. It is possible to invert the ignition output of the
E6X through the Ignition Set-up [4.6.1], which makes the output suitable for ignition systems
that do not need dwell control.
G.M. Direct Fire Ignition
The G.M. Direct Fire Ignition module (DFI), as used in the V6 Buick, can be connected
directly to the E6X ECU. This module serves both as a trigger device and as an igniter. The
DFI module has an ignition bypass input from the ECU. This input tells the DFI module to
ignore the ECU’s timing signal and fire its own spark at 10° BTDC. This gives a more
reliably timed spark for cranking. This input is controlled by the E6X through the Aux. Out
Function. To use the bypass, this function should be set in the Identification to Bypass. See
Chapter 3 [3.1]. The bypass will allow the DFI module to control spark below 450 rpm.
Ford Thick Film Ignition (TFI)
The Ford TFI module is fitted to distributors used with Ford’s EEC IV engine management
computer system. The E6X ECU can connect directly to this module; however, the TFI
module requires a trigger signal, called the SPOUT (see below), that has a 50/50 duty cycle,
which is not the standard 70/30 duty cycle of the E6X. To use the Ford TFI module you will
have to adjust the Ignition Output Duty Cycle in the Ignition Set-up (see Chapter 4 on
Accessing the Ignition Map) to 50.
Signal Names for TFI Module
PIP
Profile Ignition Pickup Output
(trigger pulses from the Hall Effect Sensor)
SPOUT Spark Out (Igniter output from the ECU) Input
POWER + 12 volts from starter circuit Input
POWER + 12 volts from ignition switch Input