MSD 6520 Digital 6-Plus Ignition Control Installation - Manual (Page 9)

INSTALLATION INSTRUCTIONS 9
M S D
• W W W . M S D P E R F O R M A N C E . C O M • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • F A X ( 9 1 5 ) 8 5 7 - 3 3 4 4
MISSES AND INTERMITTENT PROBLEMS
Experience at the races has shown that if your engine is experiencing a miss or hesitation at higher rpm, it
is usually not directly ignition. Most probable causes include faulty wiring, a coil or plug wire failure, arcing
from the cap or boot plug to ground or spark ionization inside the cap. Several items to inspect are:
• Always inspect the plug wires at the cap and at the plug for a tight connection and visually inspect for
cuts, abrasions or burns.
• Inspect the Primary Coil Wire connections. Because the MSD is a Capacitive Discharge ignition and it receives
a direct 12 volt source from the battery, there will not be any voltage at the Coil Positive (+) terminal even with
the key turned On. During cranking or while the engine is running, very high voltage will be present and no
test equipment should be connected.
WARNING: Do not touch the coil terminals during cranking or while the engine is running.
• Make sure that the battery is fully charged and the connections are clean and tight. If you are not running
an alternator this is an imperative check. If the battery voltage falls below 9 volts during a race, the MSD
output voltage will drop and the current draw will increase.
• Is the engine running lean? Inspect the spark plugs and complete fuel system.
• Inspect all wiring connections for corrosion or damage. Remember to always use proper connections
followed by soldering and seal the connections completely.
If everything checks positive, use the following procedure to test the ignition for spark. MSD also offers an
Ignition Tester, PN 8998 or PN 8996. This tool allows you to check your complete ignition system while it is
in the car as well as the operation of rpm limits, activated switches and shift lights.
CHECKING FOR SPARK
If triggering the ignition with the White wire:
Figure 11 Checking for Spark
with the White Wire.
WHITE WIRE TRIGGER
Figure 12 Checking for Spark with
the Mag Pickup.
MAGNETIC PICKUP TRIGGER
1. Make sure the ignition switch is in the “Off” position.
2. Remove the coil wire from the distributor cap and set the terminal
approximately 1/2" from ground.
3. Disconnect the MSD White wire from the distributor’s points or
ignition amplifier.
4. Turn the ignition to the On position. Do not crank the engine.
5. Tap the White wire to ground several times. Each time you pull the
wire from ground, a spark should jump from the coil wire to ground.
If spark is present, the ignition is working properly. If there is no spark
skip to step 6 on page 10:
If triggering with the Magnetic Pickup:
1. Make sure the ignition switch is in the “Off” position.
2. Remove the coil wire from the distributor cap and set the terminal
approximately 1/2" from ground.
3. Disconnect the MSD magnetic pickup wires from the distributor.
4. Turn the ignition to the On position. Do not crank the engine.
5. With a small jumper wire, short the MSD’s Green and Violet magnetic
pickup wires together several times. Each time you break this short,
a spark should jump from the coil wire to ground. If spark is present,
the ignition is working properly. If there is no spark skip to step 6
on page 10.