MSD 7720 Power Grid System - Ignition Control Only Installation - Manual (Page 5)

INSTALLATION INSTRUCTIONS 5
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PRESTART CHECKLIST
• The Power Grid 7, PN 7720, MUST be properly connected to the System Controller, PN 7730.
Consult the PN 7730 Quick Start Guide to ensure starting parameters.
• The only wires connected to the coil terminals are the MSD Orange to coil positive (+) and MSD
Black to coil negative (-).
• The MSD power leads are connected directly to the battery positive and negative terminals.
• The battery is connected and fully charged if not using a charging system.
• The engine is equipped with at least one ground strap to the chassis. Ground straps connecting
both heads to the block and then to the chassis are ideal.
TROUBLESHOOTING
Every MSD Ignition undergoes numerous quality control checks including a burn-in test. If you
experience a problem with your MSD, our research has shown that the majority of problems are due
to improper installation or poor connections.
The Troubleshooting section has several checks and tests you can perform to ensure proper installation
and operation of the MSD. If you have any questions concerning your MSD, call our Customer Support
Department at (915) 855-7123, 7 - 5 MST.
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 related. Most probable causes include 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.
• 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
10 volts during a race, the MSD output voltage will drop.
• Is the engine running lean or excessively rich? Inspect the spark plugs and 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 for spark. MSD also offers an Ignition
Tester, PN 8998. 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.