Some tuners like to use the EGO sensor at higher engine loads. This is not necessarily a bad idea,
but the limitations of an EGO sensor must be realized. As long as the Desired Air Fuel Ratio Table has
appropriate values at the higher load points, it should not be too much of a problem. Keep in mind that
high loads require richer mixtures. Most engines will detonate severely if a 14.64:1 AFR is used under
high load. When tuning the EGO in this mode, it is best to start with extremely rich numbers in the AFR
Table (like 11:1) to prevent lean-out problems.
C. Direct Fire Units (DFU’s)
Introduction
DFU’s are made by Electromotive in two variants: 2-coil and 3-coil. Each coil drives two spark
plugs in waste-spark ignition setups. Eight cylinder engines will use two 2-coil DFU’s. 2-rotor engines
will use 4 single tower coil units. Two cycle applications will use single tower coils as well.
The DFU’s are driven by a 12volt charging system housed in the
TECgt
ECU. For the
Electromotive DFU wiring requirements, refer to
Figures C.1.1-5
below.
•
2-Coil DFU’s (Part Number 070-33400)
The 2-coil DFU’s utilize three of the four terminals in their yellow connector. Here is the pin out:
Terminal A
Ground Pulse for Coil A
Terminal B
Ground Pulse for Coil B
Terminal C
Unused
Terminal D
Full-Time +12 Volt Source (9 amps)
On a standard inline 4-cylinder four-stroke application, this DFU will be used. On dual-plug 4-cylinders
two of these DFU’s will be used. Refer to
Figure C.1. 2
for terminal locations.
•
3-Coil DFU’s (Part Number 070-33600)
The 3-coil DFU’s utilize all four of the terminals in the yellow connector. Here is the pin out:
Terminal A
Ground Pulse for Coil A
Terminal B
Ground Pulse for Coil B
Terminal C
Ground Pulse for Coil C
Terminal D
Full-Time 12 Volt Source (9 amps)
On a standard 6-cylinder even-fire application, this DFU will be used. Refer to
Figure C.1. 4
for
terminal locations.
•
4- Coil DFU’s (Part Number 070-33400)
The 4-coil DFU is actually two 2-coil DFU’s. When this part number is specified, two 070-33400 DFU’s
will be used. The first DFU should be wired in the same manner as part number 070-33400. For the
second DFU, connect the coil output wires from the
TECgt
to the following terminals:
Terminal A
Ground Pulse for DFU 2 Coil (A2)
Terminal B
Ground Pulse for DFU 2 Coil (B2)
Terminal C
Unused
Terminal D
Full-Time 12 Volt Source (9 amps)
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TECgt Manual Version 2.0
- Page 36 -
©2008 Electromotive, Inc.