Can an ECU burn out a coil or is it vice versa?

[Just 6T9 CHGR]

Long story short....  Cruising along the '69 decided to sputter & stall out....crank no start on the side of the road.

Checked the obvious wiring etc & all looked good.  Unplugged my FBO ign module & plugged in my spare orange box with a ground lead....car fired right up.

Swapped in the orange box permanently on the side of the road....no start again!   This time I swapped in a spare coil....car fired right up with spare coil & module.

For shitz & giggglez & re-swapped back in the FBO module on the side of the road & nothing...crank no start.

Get the car home for more diag work.  Now I swapped back in the FBO coil....starts no problem now.  WTF?? 
Swapped in the FBO ECU...no start.

So now my dilemma....whats up with the coils?  When I got home after the ordeal the Mopar resto coil was really hot....I am running the MSD ballast that FBO provides with their kit....need to go back to a "stock" ballast to keep "stock" coil cool?

[Troy]

The stock coil needs the regular ballast or it will overheat. Your after market coil probably doesn't - or it at least uses a smaller one. Not sure why the FBO coil wouldn't still work when you first switched the boxes.

I've been fighting electrical problems for two weeks so be glad yours worked with a couple swaps...

Troy

[Just 6T9 CHGR]

Thanks Troy, figured that...I think the MSD unit that FBO provides with their ign kit is .8 ohms?  The stock one is either .25 or 1.0 ohms...cant remember.

I am so done with "modifying" shit & having it fail (although this stuff lasted 5 years)

[Troy]

I think stock would be a higher number than what you have (I pulled one that's 1.25 ohms). The .8 is recommended for electronic conversions with the stock points distributor and the .25 is recommended for the chrome box I believe. It gets a little fuzzy when you mix and match parts (ie my coil is rated for 12 volts all the time so it technically doesn't need a ballast).

Troy

[nascarxx29]

I have had these issues before with electronic ignition
If you didnt have a spare control module . With key on you could remove black yellow trigger wire from coil- terminal and put it back on and off.This sometimes re activates the module

[Charger-Bodie]

Do you have good clean contact on your engine to body ground?

[Just 6T9 CHGR]

Do you have good clean contact on your engine to body ground?

As far as I know Brian yes....new engine has been in for 4+ years now... I will double check.

Curious as to what would cause the coil to work when I initially tried the spare module and then for it not to work when I mounted the spare module securely.  Then for it to work again when I got home?
Regardless Im not going to trust that coil anymore....sad because I have a lot of work into re-lettering the FBO coil to "look" like a stock unit 

[y3chargerrt]

This is the coil I have been running for 5 or so years. Well with the sticker removed and painted black.

http://cgi.ebay.com/ebaymotors/MSD-8203-Blaster-2-Coil-W-Ballast-Resistor-/140556120850?pt=Motors_Car_Truck_Parts_Accessories&hash=item20b9cc3312

I like how the ballast resistor looks. Not stock but with the bracket it looks closer to stock then that all ceramic Mopar one.

[Just 6T9 CHGR]

I think thats the same coil that the FBO system used...I was running that same MSD resistor (.8 ohms).

For now I have reverted back to my chrome box, resto coil & stock ballast (.6ohms)

[Rolling_Thunder]

could a coil possibly overheat - causing it not to function - then after cooling off it works again ?

If so - then your FBO coil could have cooled off on the ride home then work when you hooked it back in ? 

just throwing things out there - I've never had such an issue...       I do however think Nacho is responsible 

[Just 6T9 CHGR]

     I do however think Nacho is responsible 

I concur! 

[Nacho-RT74]

     I do however think Nacho is responsible 

I concur! 

[elacruze]

could a coil possibly overheat - causing it not to function - then after cooling off it works again ?

If so - then your FBO coil could have cooled off on the ride home then work when you hooked it back in ? 

just throwing things out there - I've never had such an issue...       I do however think Nacho is responsible 

Coils can and do break down from heat (old lucas coils were not only famous for, but absolutely certain to) depending on the insulation/wire they can either short internally or open circuit and re-insulate or re-connect when they cool off, from changes in the insulation or expansion/contraction. I'll have a coil in my spares for sure. Even on my build, I went with 'stock' Chrysler coil and box instead of MSD or pertronix, because I know all the parts will work together and are available cheap at any corner parts store. Not high tech, but I'm targeting reliability. I have my ignition module mounted on the engine at the rear valley plate, where the ground can never be suspect-if it was on the firewall, I'd run a ground strap to a wiper motor stud or something to insure the chassis doesn't lose ground through paint or corrosion.

[Just 6T9 CHGR]

Thats where I have mine mounted as well....