5
Part #FAST4-101
Revised 7/9/07
FAST™
3400 Democrat Rd.
Memphis, TN 38118
Phone: (901) 260-3278 Fax: (901) 375-3408
www.fuelairspark.com
In the case of a “waste spark” setup (one coil for every pair of companion cylinders), the same
principle is used to determine where EST/COIL output A will be wired. It goes to the coil that fires the
cylinder associated with the first crank signal after the cam input. Unlike a “coil per cylinder” setup,
the number of EST/COIL outputs used is only equal to half the number of cylinders. On a “waste
spark” V8, the XIM™ fires the first four EST/COIL outputs and then starts back over at A. The
sequence is: A–B–C–D–A–B–C–D-…
OE CRANK TRIGGER:
The OE Crank Trigger ignition strategy is designed for crank trigger wheels and pickups whose output
(1, 2, 3 or 4 evenly spaced pulses per revolution) occurs just ahead of TDC – as is the case with many
older factory ignition systems.
This ignition strategy is the same as the Crank Trigger ignition strategy except that it is intended for
use with a crank input between 1 and 10 degrees BTDC. The cam input still needs to occur between 10
and 80 degrees before the crank input. The EST/COIL outputs still fire in alphabetical order starting
with output A and EST/COIL output A still goes to the cylinder associated with the first crank signal
after the cam input.
= TDC (compression)
for each cylinder
Crank
Input
Cam
Input
50*
BTDC
TDC #1
60-130*
BTDC
(Shown at 90*)
A
B
C
D
E
F
G
H
EST/COIL
Output
1
8
4
3
6
5
7
2
= Spark, approx.
30* BTDC
XIM™ – Crank Trigger Ignition Strategy
(One complete engine cycle shown for Small Block Chevy with 1-8-4-3-6-5-7-2 firing order)
