MSD 6A Install

[bahamabecomb]

I had a new in the box MSD 6AL that I wanted to try on the 340 with a Chrysler Electronic conversion disturber. I started the car this morning before changing anything and it ran fine. Removed the Chrysler ECU, put a two pin trailer plug on the green and violet wires and plugged green to black and violet to orange on the distributer, orange and black to the MSD blaster coil which was existing and the smaller red wire to the brown wire that came off the coil, connected the heavy red and black from MSD to the battery. I also put a jumper on the ballast resistor. I had no spark when cranking the engine, so I then ran the smaller red wire directly to the battery and still do not have spark. I get a constant red flash and then five blinks on the box when the key is turned on. I purchased it about 6 months ago and it has never been out of the box, but I can't find any wiring issues. Any suggestions?

 

[jimjimjimmy]

if you want to check the system find the unused white wire turn the key on plug a spark plug into the coil wire ground it then strike the white wire to a ground and you should have spark at the plug if it is working or hooked up right . hope that is understandable .

 

[jimjimjimmy]

when i say turn the key on i mean power to the small red wire .

 

[Professor Fate]

A pic of how you jumpered the ballast would help.

 

[67Dart273]

There is or was a troubleshooting document on the 6 series at MSD or Holley or whoever it is now

You must have the white wire taped off. you must have the big black to a good ground, and the big red to constant "good" battery, such as say, the big stud on the start relay. The small red connects to switched 12V and works sorta like a relay trigger wire

So far as the resistor bypass, you can get into trouble with this. You MUST have the IGN2, usually but not always brown, jumpered to the blue "run" wire

When you twist the key to "start," the RUN circuit GOES DEAD. The only power to the ign system is the (normally brown) IGN2, which comes alive in "start" same as the yellow start wire. It is however, a separate switch contact in the ignition switch

Another issue is if the two pickup wires are not correct, this will move the timing AKA when the spark fires rotationally incorrect in relationship to the rotor/ cap contacts. Google search "rotor phasing" if you are not familiar

 

[Valman]

If you have an electric choke on the carb, don’t run it to the ignition coil positive if you’re using an MSD.

I had a similar issue once with an MSD, they can be very sensitive. Took the electric choke supply off, started.

 

[Bewy]

[1] The test in post #2 does not guarantee that the box is ok if grounding the white wire produces a spark. All it proves is that part of the circuitry is working. The mag trigger input may not be working.
Was the bal res shorted to supply the small red wire to the box?

 

[jimjimjimmy]

[1] The test in post #2 does not guarantee that the box is ok if grounding the white wire produces a spark. All it proves is that part of the circuitry is working. The mag trigger input may not be working.
Was the bal res shorted to supply the small red wire to the box?

whatever you say but that is the only test MSD recomneds to test the box . i talked to them about it not long ago .

 

[Demonx2]

whatever you say but that is the only test MSD recomneds to test the box . i talked to them about it not long ago .

I used that very test when I first wired up the avatar with an MSD6AL. No spark during crank but that test showed it would fire the plug. So I knew the next step was to look at the reluctor gap.

Yep, found it way too wide in my new distributor. Set it to .008" and the car instantly fired up. Been running fine ever since!

So try the test and move to the pickup/reluctor check next as appropriate.

 

[67Dart273]

If you have an electric choke on the carb, don’t run it to the ignition coil positive if you’re using an MSD.

I had a similar issue once with an MSD, they can be very sensitive. Took the electric choke supply off, started.

Heh. Well that is because MSD or any other CD DOES NOT have 12V or any DC running to the coil, and the coil NEG is grounded. This is part of why tachs don't work without special adapters. The way a CD works, is it charges up a big cap similar to a photoflash, and when triggered, discharges a big pulse from the cap to the coil to generate the spark.

On that note, with an MSD or other CD, DO NOT connect ANY OTHER wiring to the coil except the wires from the CD unit. This includes the original radio suppression cap, leave it unconnected.

 

[Scody21]

You could also have the polarity wrong on the distributor, how the violet and Green leads hook up, this puts you out a phasing.

If you get crafty, you can run a switch to turn the power on for the MSD box outside of the column so you don’t need the run circuit of the column to make the MSD box run. Just have to play with the run / start circuits so they’re wired together to operate the starter.

 

[Valman]

Heh. Well that is because MSD or any other CD DOES NOT have 12V or any DC running to the coil, and the coil NEG is grounded. This is part of why tachs don't work without special adapters. The way a CD works, is it charges up a big cap similar to a photoflash, and when triggered, discharges a big pulse from the cap to the coil to generate the spark.

On that note, with an MSD or other CD, DO NOT connect ANY OTHER wiring to the coil except the wires from the CD unit. This includes the original radio suppression cap, leave it unconnected.

Yeah I get that, it was purely an oversight at the time. Point I was making was to not have anything ‘auxiliary’ connected to the MSD.

 

[Valman]

Yep, found it way too wide in my new distributor. Set it to .008" and the car instantly fired up. Been running fine ever since!

I bought an MSD distributor that had a huge reluctor gap out of the box - like 1/8’’. I made a spacer for it to bring it back to spec.

 

[bahamabecomb]

Thanks for the help, electric choke wire was still connected to the coil and once removed it fired right up. Should have read the instructions closer where it says "NO OTHER WIRES TO BE CONNECTED TO THE COIL". Anyway glad to have it running now and hopefully it will dry out here soon so I can take it for a spin.