MSD junk or....

Twin_Turbo

Twin_Turbo

Der Maulwurf
Joined
Mar 5, 2008
Messages
7,575
Have a prob w/ an MSD 6 Digital. Installed it, worked fine. After a couple of times starting the car it's now dead. The engine is new, tuning the EFI so it only idled a bit and was running for some short intervals.

The led light does not always come on with the ign. key in the on position. I thought it was an ign. switched 12V problem but it isn't, it's also not a ground prob. The 6 is wired directly to the battery, all wiring is brand new, even the battery cables and all ground cables on the engine, all heavy oversized copper cables. All connections are weatherpack and soldered.

If I unhook the neg. battery cable and then hook it back up and then turn the ign. on the led illuminates. When cranking it flashes but when turning the key off and back on again the led never comes back on unless I remove the neg. cable again. It's like some internal component needs to bleed off (capacitor) or it won't work. With led flashing there is no spark. I have it wired so that I have a "plug" that I can plug in place of the weartherpack to the ignition so that it completely bypasses the msd system (have been stranded before LOL) and bypassing it the car runs just fine.

I'm 99.9999% sure the digital 6 is dead but I am wondering how this is possible. What would cause these things to just die? I've had it happen before with a msd 6 and a crane box. Are these things just not durable enough? Either they last for a long time or they die soon after installing. I think the crane one lasted 5 minutes. It was an older blue one, have used 3 of the black ones and never had a prob again.
 
:shocking: MSD makes crappy electronics, many complaints over the years, and including ONE example from me, and maybe 2 friends with same shit....

and IMO, the only thing MSD brought to the table was to smooth out a rich idle, other than that, I never noticed a dimes worth of difference...:shocking:

and with an HEI system, I never even noticed that much.....:beer::bomb:
 
Some guy here in NL was looking for old boxes, I had 4 lying aronud... all MSD. All have the same symptoms. Flashnig leds frmo crank signal but no spark or only low rpm multispark but missing and sputtering at higher rpms. Never had a prob w/ the mallory one, also sold as summit brand (never used summit brand however)
 
I remember messing with a basic old Mopar/Chrysler conversion on a Pontiac back in the mid 70's...in fact that is the system that introduced the kid's mom and me....:shocking:

but other than the MSD and that old setup, I never did any other ignition work except to convert everything to an HEI, which has NEVER missed a lick for me, nothing not easy enough to fix, anyway....

ONE time I had a HEI with a open coil primary...so no +12 on the tach output line, once glance, soldered the crimp terminals to the wires, ran for years....:shocking:
 
problem is, once you go to some higher comp. stuff and higher rpms the hei doesn't cut it and you are forced to run something else
 
Twin_Turbo said:
problem is, once you go to some higher comp. stuff and higher rpms the hei doesn't cut it and you are forced to run something else
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:shocking: I have heard yes, and no on that point, damn if I know, I don't race anymore, so 5k rpm is pretty tight for me, but I an old Pontiac driver, and 5k is about all one could get outta one of them old iron heads without going hog wild....so we all built them for TORQUE 550 ft lbs at idle....:devil: how in hell else to get 5500 lbs moving??

:beer:
 
Twin_Turbo said:
problem is, once you go to some higher comp. stuff and higher rpms the hei doesn't cut it and you are forced to run something else
Click to expand...

I would consider a slightly lower inductance aftermarket coil on an OEM distributor to help out the higher RPM spark demands. Better charging, and excellent reliability.

Regarding the MSD unit, is it possible to look inside it, or is it all encapsulated with epoxy?
 
I know how to test them by grounding the trigger wire, I went over it all a couple of times...it's not a connection, everything is wired OK, all brand new weatherpack and large battery cables..it's a perfect install. The digital 6 is of course fully potted but I don't want to pull it apart..maybe there's a warrenty on it...its brand new. It's said to have all kinds of smart electronics and self diagnosing...well, it won't diagnose its own death that's for sure.

A magneto is out of the question, it still has to idle OK. EFI depends on it.

Everyone always puts down those mallory unilites...I have never ever had a problem with one. This car has a unilite too, it works perfectly. If there is one system that is supposedly burnt out imediately with a bad ground or noisy voltage it's that so they say.....it's still alive and kicking.
 
Others say leaving them in the car when welding kills them.
 
No welding was done, just starting the car and adjusting the efi fuel mixtures...nothing out of the ordinary.
 
Ol' Red had the K-66 TI from the factory- the PO had bypassed it and installed a Chrysler module and rewired for that. I yanked that and used a SUmmit branded Mallory box (cheaper than MSD). Ran fine but seemed to not want to idle very well. Then I got curious if the old TI even still worked- rewired back to the factory stuff. Thing starts and runs better with that old TI system than it ever did with either the chrysler module OR the summit box.
I had some concern with the magnetic pickup in the dizzy- the lower bushing in the factory dizzy was worn out badly- so I got an MSD mag pickup dizzy with tach drive. Output of both the factory and the MSD dizzy is the same.

Speaking of that-- BIRD- you ever get that thing rebuilt??
 
Twin_Turbo said:
No welding was done, just starting the car and adjusting the efi fuel mixtures...nothing out of the ordinary.
Click to expand...

Possibly just "infant mortality", where a module passes final-assembly electrical tests prior to shipment, but an internal part fails shortly thereafter out in the field. Short of a 50 hour burn-in of every module prior to shipment, it's difficult to catch those parts. You have to rely on your parts supplier not sending you semi-faulty parts.

Outside of getting MSD to exchange the module on a real or "informal" warranty, I don't know what to suggest.
 
big2bird said:
rtj said:
Others say leaving them in the car when welding kills them.
Click to expand...

I would belive that.;)
Click to expand...

My welder buddy is really freqed out about that electronicus crappicus on board when he does his TIG machine....but the exhaust guy down the street does MIG all the time on exhaust systems....never an issue....so go figger...

:sos::(:stirpot:
 
Bad rev limiter plug in? It is doubtful that would fix it, but I've seen a lot of unusual failures over the years.
 
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