i have a query on behave of a friend that's playing with an old Mustang. seems i have heard of his trouble here b4 but i don't find what i think i read about in my searches.

he has an MSD system that is problematic. drives the car 300-500 miles a year. every 3 years, the MSD box quits. he says it gives no voltage to the coil. he says MSD tech support is blaming the failure on the process by which he disconnects his battery charger.

the charger story sounds like a lot of malarkey to me.

wasn't there something like this run thru here a few years ago? he says he's been thru 3 boxes. guess he's had the car awhile.

D~~~!

Sounds like typical MSD "reliability" to me. Send your friend over to read about the HEI upgrade, which is just as easily done on a Ford as on a Mopar; he'll wind up with equal or better spark quality and greater reliability.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Has he ever sent a box back to MSD for diagnosis and repair? I'm thinking this Mustang likely has an electrical problem. I would start checking over the charging system and grounds.

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Joshua

How does he disconnect the battery charger?

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

3 answers)


@ Josh. . .
as i understand it he has sent the box back in. and it cost him more in repair charges.

@ EMS. . . .
as for the battery charger. the issue is as to whether he removes the positive post 1st, or not. i know i don't pay much attention to that detail when i use a charger. he doesn't either, but now he's thinking about it.

@ Dan. . . .
i'll point him that way, but i think he's got enuff $$$ into his setup that he's not going to eagerly abandon it.

D~~~!

Add a mechanical relay so the MSD box only gets power on the main power lead if the ignition is on.

Normally the MSD is constantly hooked up to power and has another (smaller) lead to turn it on (it's either a internal relay or most likely a solid state relay (MOSFET))

I did this with my MSD because I didn't like the idea of it always being supplied with power and haven't had any problems with it for 20 years.


Also, with the mechanical relay, the charger disconnect wouldn't matter because it won't be online when your connecting or disconnecting the charger.


And put it on a 20 amp fuse (before the relay) I'm assuming a 6A for the fuse, contact MSD if not a 6A for correct rating..

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yes, they charge for repairs, but what did they fix inside the unit? Knowing what failed may give a good indication as to why it failed.

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Joshua

Doing the same thing again and again, expecting a different result, is a good working definition of insanity.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

i'll sse if he has the details as to what the fixed.

BTW, I repaired a very old MSD-7 box of Charlie S'. MSD told Charlie they couldn't fix it because they couldn't get parts. Liars. I went right to Allied Electronics' web site and ordered everything I needed. I paid twice for shipping what the actual parts cost. Two power transistors, two resistors and a diode was all it took if memory serves. Props to the person who worked up a schematic of the MSD-6 and put it on-line as his MSD-7 is schematically very much like the analog MSD-6.

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Joshua

I couldn't be happier, it is still working, and the price was a lot better then a new box.
PS: It is old, purchased about 1975

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

msd must be junk just like mopar gold race box, i have been racing the same box for 12yrs now and i can`t seem to break it so i can move on to the top line chevy gear!!!!!!!

Yes, well, things do have a tendency to work differently in Newfoundland, don't they.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

it has been for longer than i am here