famous bob
mopar misfit
will a msd 6 work at all if its bad, after up to operating temps , car is very undependable , cutting out, dieing ,but will restart -------------???
msd 6
- Thread starter famous bob
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Scody21
Just send it
Download the MSD manual and follow the test to check the box and also the coil test. Sounds to me like your coil is done..
I agree that the coil would be the first suspect. When an msd goes its usually sudden and doesnt work again. A coil typically fails slowly and symptoms start when it gets hot. Its not uncommon for a coil to fail but then work fine again once it cools off.
famous bob
mopar misfit
changed coils , a long while ago , still does it ----------------------? thanks tho
Have you confirmed a loss of spark when the car is acting up?
Scody21
Just send it
Have you ran an ohm meter on your spark plug wires? Also checked the pickup wires to the MSD, and to see if your getting voltage drop to the MSD box.
Dave999
Well-Known Member
old style MSD6 AL and derivatives with decrete components rather than the machine solderd ones of today occasionally corrode inside the case....well they do in the UK.... leaves a lot of dust floating about which if moist due to humidity or damp weather can cause intermittent shorts/arcing..... this is the type with the riveted-on flat plate backing, the holes down the middle of the rivets are used for mounting.... they are not particularly well sealed...
take it apart (4 rivets and a cable clamp) clean the oxide off the case. paint inside with transformer paint. scratch off varinsh on board to replace components with burn marks, look also for the 3 wire links,(fuses) replace if burnt through, re varnish... good to go... if the old style unit wistles or buzzes when both red wires have 12 volts its good, you may need a dog or small child to hear this for you....
not a lot in there, and only the choke/transformer has had its part number missed off/ removed everything else is general commodity electronic components
modern ones... same old 1968 design for the buisness end, just built by a robot not a person, with bells and wistles added via a micro chip based controller device, allows rev limit and launch rpm facilities. but delibertly not user servicable, no obvious part numbers on a good few vital 3 pin components, lots of wires to buttons and adjsuters on the outsde of the case, deiberatley made hard to understand to stop people copying.
Unless you have a microscope for eyes and tiny soldering irons for fingers... forget it mobile phone shop may be able to fix... they will have a workstation for doing micro soldering.
as with many things if the box doesn't have a good ground point...it dosesn't work as well as it should.
Dave
take it apart (4 rivets and a cable clamp) clean the oxide off the case. paint inside with transformer paint. scratch off varinsh on board to replace components with burn marks, look also for the 3 wire links,(fuses) replace if burnt through, re varnish... good to go... if the old style unit wistles or buzzes when both red wires have 12 volts its good, you may need a dog or small child to hear this for you....
not a lot in there, and only the choke/transformer has had its part number missed off/ removed everything else is general commodity electronic components
modern ones... same old 1968 design for the buisness end, just built by a robot not a person, with bells and wistles added via a micro chip based controller device, allows rev limit and launch rpm facilities. but delibertly not user servicable, no obvious part numbers on a good few vital 3 pin components, lots of wires to buttons and adjsuters on the outsde of the case, deiberatley made hard to understand to stop people copying.
Unless you have a microscope for eyes and tiny soldering irons for fingers... forget it mobile phone shop may be able to fix... they will have a workstation for doing micro soldering.
as with many things if the box doesn't have a good ground point...it dosesn't work as well as it should.
Dave
"as with many things if the box doesn't have a good ground point...it dosesn't work as well as it should."
MSD box itself does not need to be grounded. The ground is done with the black wire, the case is isolated. In fact, they ship with rubber isolators to reduce vibration.
MSD box itself does not need to be grounded. The ground is done with the black wire, the case is isolated. In fact, they ship with rubber isolators to reduce vibration.
famous bob
mopar misfit
have changed coils , first thing I thot about , also many other changes , runs like a 505 should till I hit a bump , then dies ...but will restart , suspect a wire grounding some where when I hit that bump...
Like I have seen, every racer has a extra box in their trailer. There's a reason for that yet many here have used MSD systems on their street cars for years with no issues. It's probably a box.
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