MALLORY IGNITION
550 MALLORY WAY, CARSON CITY, NV 89701
4
TACHOMETER COMPATIBILITY LIST
Aftermarket
White Wire
Magnetic Trigger
Tachometer
Trigger
Connector
Autogage
29074
29078
Autometer
Ford Motorsport
Moroso
Stewart
29074
29078
S.W. & Bi Torx
Sun
29074
29078
VDO
8910
29078
AMC (Jeep)
29074
29078
Chrysler
29074
29078
Ford (Before 1976)
29074
29078
Ford (After 1976)
29074
29078
GM
Bypass in-lin
Bypass in-line
filter
filter
Imports
29074
29078
TROUBLESHOOTING
This section offers several tests and checks you can perform to en-
sure proper installation and operation of the HYFIRE
®
VIA Ignition
Control. If you experience a problem with your HYFIRE
®
VIA, first
check for proper installation and poor connections. You can eliminate
many problems by checking these items. If you have any questions
concerning your HYFIRE
®
VIA Ignition Control contact the Mallory
Technical Service Department at 775-882-6600, Monday through Fri-
day, 8:00 am to 5:00 pm Pacific time.
Tach/Fuel Adapters
If your tachometer does not operate correctly, you probably need a
Mallory tach adapter. Consult the Tachometer Compatibility List at
right for common tachometers and compatible tach adapters.
No-Run on Foreign Vehicles
Some foreign vehicles with fuel injection systems may require a ta-
chometer/fuel injection adapter to run with the HYFIRE
®
VIA Ignition
Control. Often, the same trigger source is used to operate an ignition,
tachometer, and fuel injection. This results in a voltage signal that is
too low to trigger the fuel injection. A tach/fuel injection adapter will
usually solve this problem.
Inoperative Tachometers
If your tachometer fails to operate with the HYFIRE
®
VIA installed, you
may need a Mallory tach adapter. Before purchasing a tach adapter,
try connecting your tachometer trigger wire to the yellow wire of the
HYFIRE
®
VIA Ignition Control. This output produces a 12 volt, square
wave. If the tach still does not operate, you will need a tach adapter.
Two different tach adapters are available:
PN 29078
If you are using the magnetic pickup connector (green
and violet wires) to trigger the HYFIRE
®
VIA, you will
need this adapter.
PN 29074
If your tach was triggered from the coil negative termi-
nal (voltage trigger) and you are suing the white wire
to trigger the HYFIRE
®
VIA, you will need this adapter.
Ballast Resistor
If you have a current trigger tach (originally connected to coil (+) posi-
tive) and use the white wire of the HYFIRE
®
VIA for triggering, you can
purchase a Chrysler Dual Ballast Resistor (1973-76 applications). Wire
it as shown in Figure 3.
Engine Run-On
If your engine continues to run even when the ignition is turned off,
you are experiencing engine run-on. Usually, older vehicles with an
external voltage regulator are susceptible to this condition. Because
the HYFIRE
®
VIA Ignition Control receives power directly from the
battery, it does not require much current to keep the unit energized. If
you are experiencing run-on, it is due to a small amount of voltage
going through the charging lamp indicator and feeding the small red
wire (even if the key is turned off).
GM 1973-83 with Delcotron Alternators
GM Delcotron alternators use an internal voltage regulator. Install the
diode inline on the smallest wire exiting the alternator (see Figure 5).
It is usually a brown wire.
Most other applications: To eliminate run-on, place a resistor in-line to
the HYFIRE
®
VIA small red wire to keep voltage from leaking into the
HYFIRE
®
VIA Ignition.
SMALL RED
FROM HYFIRE® VIA
12 VOLT
IGNITION SWITCH
CHRYSLER DUAL
BALLAST RESISTOR
WHITE WIRE FROM
HYFIRE® VIA
FROM POINTS OR
AMPLIFIER
FIGURE 3
Early Ford and GM: To solve the run-on problem, a diode is supplied
with the HYFIRE
®
VIA Ignition Control. By installing this diode in-line
of the wire that goes to the charging indicator, the voltage is blocked
from entering the HYFIRE
®
VIA Ignition Control. Figure 4 shows the
proper diode installation for early Ford and GM vehicles.
NOTE: Diodes are used to allow voltage to flow only one way.
Make sure the diode is installed facing the proper direction, as
shown in Figure 4.
Ford: Install the diode inline to the wire going to the #1 terminal.
GM: Install the diode inline to the wire going to the #4 terminal.
VOLTAGE
REGULATOR
1 2 3 4
FOR EARLY GM VEHICLES
ATTACH DIODE TO
#4 TERMINAL
FOR FORD VEHICLES
ATTACH DIODE TO
#1 TERMINAL
1A-100V DIODE
TO CHARGING LIGHT
SPLICE HERE
FIGURE 4
DELCOTRON
ALTERNATOR
1A-100V DIODE
TO CHARGING LIGHT
SPLICE HERE
FIGURE 5