battery death by MSD?

1984 GT · 11-20-2003, 06:51 AM

Does anyone have any experience with an MSD 6al draining the battery?

I installed a 6al on my 84 Mustang and it seems to perform fine. Three days after the install my battery was dead. I replaced the battery and now three days later my new battery is dead. Could it just be a coincidence that my charging system started having problems at the same time I did the MSD install?

Any help is appreciated.

tmoss · 11-20-2003, 08:33 AM

Could be your alternator too. If you want to experiment, remove the large charging cable from the alternator and let it sit for 2 days and see if it drains. If it doesn't, pull the main 12v feed to the MSD and let it sit whichever eliminates the loss of charge is it.

1984 GT · 11-20-2003, 08:46 AM

Thanks. When the new battery went in I read voltage at the battery with the car running and it was about 14 volts would this not indicate that the alternator and voltage regulator are working OK?

Mustang_289 · 11-21-2003, 03:39 PM

If you put a meter across your battery while the motor is running and you see voltage higher then 12.5 you're charging system is working fine. Normally you'll see in the 14.something range.

1984 GT · 11-21-2003, 04:00 PM

Thanks for the info, I had already checked at the battery to see if my alternator was working and it was, the next time I checked it wasn't.

I've given up and taken it to a shop where they tell me there is something shorting out the alternator...they replaced it and burned out the new one.

They are looking for the short as we speak.

dragstang86 · 11-22-2003, 12:01 AM

My MSD 6al drains my battery down if it sits for awhile without being started. I am sure it is the MSD because if i disconnect the hot wire to the MSD box when it sits for awhile the battery holds the charge fine. But if i leave the hot wire on there after a week or so its dead as can be.

bigred90gt · 11-22-2003, 05:26 PM

I dont think it is the msd. I leave mine all hooked up and dont drive it for 2 or 3 weeks at a time, and it cranks immediately every time.

NO SLO PK · 11-22-2003, 08:59 PM

I don't think it's the MSD either. I barely drive my LX (maybe 300 miles a year). I only start it to move it around. I start it maybe once every two weeks.

Not once has the battery drained.

1984 GT · 11-24-2003, 07:39 AM

OK, my problem was a short in the signal wire from the ignition switch to the voltage regulator. So, the alternator was not getting the message to start charging the battery when the car was running.

I couldn't locate exactly where the short was so I ran a new wire from a switched source to the voltage regulator, so far so good.

While trying to figure this out I did have a conversation with the MSD help line and was told there is a posibility of a bad capacitor in the box that could cause a voltage drain to the system.

tmoss · 11-24-2003, 08:26 AM

Yeah, they use elctrolytic capacitors and they can go bad. If you have a 6A and their not going to repair under warranty, you can take the back cover off as see the capacitors - the electrolytics often leak and go bad. Not hard to replace, just have to have the millifarad and voltage rating to replace it. I have a 6M in my boat that wnet bad - it's potted in expoxy, so no repairs possible.

11-20-2003, 06:51 AM	#1
1984 GT Registered Member Join Date: Mar 2002 Location: Gainesville, Fl Posts: 59	battery death by MSD? Does anyone have any experience with an MSD 6al draining the battery? I installed a 6al on my 84 Mustang and it seems to perform fine. Three days after the install my battery was dead. I replaced the battery and now three days later my new battery is dead. Could it just be a coincidence that my charging system started having problems at the same time I did the MSD install? Any help is appreciated. __________________ If not now, when?

11-20-2003, 08:33 AM	#2
tmoss Registered Member Join Date: Mar 2003 Location: Saint Louis, MO Posts: 634	Could be your alternator too. If you want to experiment, remove the large charging cable from the alternator and let it sit for 2 days and see if it drains. If it doesn't, pull the main 12v feed to the MSD and let it sit whichever eliminates the loss of charge is it. __________________ Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/

11-20-2003, 08:46 AM	#3
1984 GT Registered Member Join Date: Mar 2002 Location: Gainesville, Fl Posts: 59	Thanks. When the new battery went in I read voltage at the battery with the car running and it was about 14 volts would this not indicate that the alternator and voltage regulator are working OK? __________________ If not now, when?

11-21-2003, 04:00 PM	#5
1984 GT Registered Member Join Date: Mar 2002 Location: Gainesville, Fl Posts: 59	Thanks for the info, I had already checked at the battery to see if my alternator was working and it was, the next time I checked it wasn't. I've given up and taken it to a shop where they tell me there is something shorting out the alternator...they replaced it and burned out the new one. They are looking for the short as we speak. __________________ If not now, when?

11-22-2003, 12:01 AM	#6
dragstang86 Registered Member Join Date: Sep 2002 Location: baltimore, md Posts: 220	My MSD 6al drains my battery down if it sits for awhile without being started. I am sure it is the MSD because if i disconnect the hot wire to the MSD box when it sits for awhile the battery holds the charge fine. But if i leave the hot wire on there after a week or so its dead as can be. __________________ 90 LX Hatchback 306, AFR 165's 58cc, E303, 1.6 roller rockers, 70mm throttle body, cobra intake, bbk fenderwell, bbk longtubes, x-pipe, flowmasters, pullies, msd 6a, crane ps-92, stock MAF sensor, electric fan, No AC, No air pump, flaming river quick ratio rack C-4, 3500 stall, 373's, aluminum driveshaft SSM Lift bars, , sub frame connectors, strut tower brace 12.57 @105.12mph w/ 1.686 60ft before bbk longtubes (with equal shorties) ----------------------------------------- 86 tube chassis coupe - the trailor queen

11-21-2003, 03:39 PM	#4
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	If you put a meter across your battery while the motor is running and you see voltage higher then 12.5 you're charging system is working fine. Normally you'll see in the 14.something range.

11-22-2003, 05:26 PM	#7
bigred90gt 2 Stangs in the Stable Join Date: Apr 2002 Location: Baytown, TX Posts: 1,209	I dont think it is the msd. I leave mine all hooked up and dont drive it for 2 or 3 weeks at a time, and it cranks immediately every time. __________________ '90 GT Under construction Best E.T. = Fast @ High Speeds - OK So I Lie. So What!!! 04 F-150 STX 4.2L 5 spd Rice Haters Club Member #128

11-22-2003, 08:59 PM	#8
NO SLO PK Registered Member Join Date: Mar 1999 Location: Arcadia, CA, USA Posts: 731	I don't think it's the MSD either. I barely drive my LX (maybe 300 miles a year). I only start it to move it around. I start it maybe once every two weeks. Not once has the battery drained. __________________ Russ L '91 LX - 331 w/ Procharger '03 Cobra Convertible - Pullied '94 Lightning '65 Mustang Coupe

11-24-2003, 07:39 AM	#9
1984 GT Registered Member Join Date: Mar 2002 Location: Gainesville, Fl Posts: 59	OK, my problem was a short in the signal wire from the ignition switch to the voltage regulator. So, the alternator was not getting the message to start charging the battery when the car was running. I couldn't locate exactly where the short was so I ran a new wire from a switched source to the voltage regulator, so far so good. While trying to figure this out I did have a conversation with the MSD help line and was told there is a posibility of a bad capacitor in the box that could cause a voltage drain to the system. __________________ If not now, when?

11-24-2003, 08:26 AM	#10
tmoss Registered Member Join Date: Mar 2003 Location: Saint Louis, MO Posts: 634	Yeah, they use elctrolytic capacitors and they can go bad. If you have a 6A and their not going to repair under warranty, you can take the back cover off as see the capacitors - the electrolytics often leak and go bad. Not hard to replace, just have to have the millifarad and voltage rating to replace it. I have a 6M in my boat that wnet bad - it's potted in expoxy, so no repairs possible. __________________ Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/

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