6425 Datasheet, PDF (2/20 Pages) Alpha Wire – CUSTOMER PRODUCT SPECIFICATION

2
INSTALLATION INSTRUCTIONS
LED INDICATOR
A red LED is located on the top of the MSD 6AL. It is used to monitor the current status of the 6AL
ignition.
Key power ON-engine
OFF
Key power ON-engine
OFF
Key power ON-engine
cranking
Key power ON-engine
cranking
One long flash
One long flash + 5
short flashes
Continuous flashing
No flashing
6AL box is
functioning Normal
6AL box is
functioning Normal
6AL box is
functioning Normal
6AL box is
functional
Rev Limiter verification
function active (ON)
Rev limiter verification
function deactivated (OFF)
LED flashes each time the
ignition fires
Check Power, ground and
crank sensor connections
Note: When the engins is running, the LED will appear to be ON. This is normal and is due to the
rapid flashing of the LED on each ignition firing event.
Note: Solid Core spark plug wires cannot be used with an MSD Ignition.
Note: Do not use digital or dial-back timing lights.
REV LIMITER
The Digital 6AL features a built-in Soft Touch Rev Control that provides a smooth and accurate rev
limit by dropping the spark to individual cylinders. The Soft Touch produces a load-free rev limit that
is within 1% of the selected rpm.The rpm limit is adjusted in 100 rpm increments with the sealed
rotary switches under the black cover on top of the 6AL.
CYLINDER SELECT
The MSD is programmed at the factory for use on 8-cylinder engines. If you are installing it to a different
engine you will have to program the Ignition. This is easily achieved through the cylinder select wire
loops on the side of the ignition. Page 5 outlines setting the cylinder select.
GENERAL INFORMATION
BATTERY
The Digital 6A and 6AL will operate on any negative ground, 12 volt electrical system with a distributor.
The MSD can be used with 16 volt batteries and can withstand a momentary 24 volts in case of jump
starts. The Ignition will deliver full voltage with a supply of 9 - 18 volts.
If your application does not use an alternator, allow at least 15 amp/hour for every half hour of
operation. The MSD uses about .9 Amps for every 1,000 rpm. If the engine is cranked with the same
battery or other accessories such as an electric fuel or water pump are used, the amp/hour rating
should be higher.
COILS
The Digital 6A and 6AL Ignition can be used with most stock coils and aftermarket coils designed to
replace the stock coils. The line of MSD Blaster Coils are great for street and mild racing. For extended
high rpm operation the Blaster HVC, PN 8252 or HVC II, PN 8253, are recommended. For more
information on recommended coils, check with our Customer Service Department at [phone].
TACHOMETERS
The MSD Ignition features a Gray Tach Output wire that provides a trigger signal for tachometers, a
shift light or other add-on rpm activated devices. The Tach Output wire produces a 12 volt square
wave signal with a 20% duty cycle.
Some vehicles with factory tachometers may require a Tach Adapter to operate with the MSD. For
more information on Tachometers and MSD Tach Adapters, see the Tachometer Section on page 6.
If your GM vehicle has an in-line filter it may cause the tach to drop to zero on acceleration. If this
occurs, bypass the filter.
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