How to Check Your MSD Ignition Box
For the Racer who feels they have a failed MSD®Ignition, there is a simple test that walks you through to confirm a true failure of your MSD®Ignition.
First you will need a Volt/Ohm meter (this check can be performed with an analog or digital meter as well). The type of meter will not change the outcome of the test performed. Set your volt/ohm meter on the 1k ohms scale, then position the MSD®Ignition in approximately the same orientation as mounted in the vehicle. This is done to ensure that the MSD®Ignition is relatively in the same position as when the failure occurred. Next take either lead and attach it to a bare metal area on the MSD®Ignition. The second lead needs to be hooked to the Large Red wire that provides your main 12vdc input. In an Undamaged MSD®Ignition the needle will stay in the home position (i.e. max Ohms for scale chosen). A Damaged MSD®Ignition will show a reading of 3k ohms or lower.
The readings mentioned above are the result of experience with repairing MSD®Ignition systems. If you plan on testing your MSD®Ignition while it is still mounted in your vehicle PLEASE remove the LARGE RED wire (i.e. main 12vdc). Failure to do this will result in possibly damaging your meter while performing this test on your MSD®Ignition.
Troubleshooting MSD ® Ignition 6A, MSD ® Ignition 6AL, MSD ® Ignition 6T, MSD ® Ignition 6ALN, MSD ® Ignition 6TN, MSD ® Ignition HVC 6600, MSD ® Ignition 7AL-2
MSD ® Ignition High Speed Miss:
Check the main ground connection & + 12VDC connection on the MSD ® Ignition box for a good connection. Also look at the Orange & Black coil wire connectors coming out of the MSD ® Ignition for poor fit or wire corrosion. Check to make sure that the second trigger input out of the MSD ® Ignition is not shorting to ground. IE (the trigger you are not using). If you have taped it off make sure it is still clean and dry with no way to make a connection to ground!
MSD ® Ignition RPM limited / flat performance of a MSD ® Ignition:
Check the small Red wire coming out of the MSD ® Ignition for a loose connection or a poor wire connection at the switched +12vdc. A loose main Black ground wire out of the MSD ® Ignition to the chassis ground / Battery ground. Check to make sure you have a solid +12vdc to the MSD ® Ignition box. If the voltage drops below +10.35vdc the MSD ® Ignition can start to cause gremlin kind of issues. Check the Orange & Black ignition coil wires coming out of the MSD ® Ignition at the coil side for poor fit or bad crimping of the connector.
MSD ® Ignition will not start the vehicle:
You will want to start with the Basics. Make sure you have a solid +12vdc & Ground to your MSD ® Ignition check all connection points! Check the small Red wire coming out of the MSD ® Ignition box for breakage and poor connection at the switched +12vdc source. Make sure the+12vdc being supplied is not drifting around on your MSD ® Ignition, this will cause your unit to do dumb things. Remember if the voltage gets below the +10 volt range the MSD ® Ignition box will shut down period.
A 6A or 6AL either will work but if you want more punch on the output of the box then the 6al is the better choice. If you are you running with the Blaster 2 coil, you need to move up to either of the following coils - AutoZone C-839 or CarQuest FD-478. They are TFI type coils, they are quicker reacting then the Blaster2 and Do Not heat soak and lose output. And as a side benefit they are the units that MSD sells as the HVC stuff at a high price! These coils will get everything out of your MSD box there is to get, the only thing you will need to do is make a mounting bracket. Use aluminum L channel, a couple of bolts and Ny-lock nuts & ready to roll. Also these coils can be mounted in any orientation and still function they don't care.