I did a GM alternator swap and wired according to tech link here. I also added an electronic ignition from J.T. Outfitters and added a tach. Now my battery is dead if I dont drive it every couple of days. My question is...Is there a way to hook some sort of guage up that will let me know when i find what is drawing the current when I have the ignition off??
battery always dead (1 Viewer)
- Thread starter 74cruiserintexas
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Just put a test light between the negative terminal on the battery and the disconnected negative cable end. If there is a draw, the light will light. Disconnect the stuff you did most recently first, then start pulling fuses. When you find the draw, the light goes off.
Good luck
Good luck
Hi, My first thought is: Did you use a used alternator? Even if you used a re-man try disconnecting the battery, disconect the large wire on the alt., keeping it isolated untill you reconnect the batt. then touch the wire to the terminal on the alt. and check for sparks. If you see a spark, the alt. has a bad diod and is draining your batt. Hope this helps, as the dist. is wired to the ignition switch, and cant do a drain! Earl
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Gumby, awesome advice! Never thought about checking it that way. I guess you DO learn something new every day 
- Thread starter
- #5
Thanks....I will try the test light and find the problem. I usead an alternator from O'Reiley auto parts but I suspect it will probably be the problem.
- Thread starter
- #6
Well, the alternator is the problem. I remove the large charge wire and the draw quits.  oes this mean I have a bad diode?
oes this mean I have a bad diode?Like the others said you can have a bad diode that will allow current flow but the alternator will still charge. It's not real common but it can and does happen.
Many rebuild shops don't change out the diodes as long as the alt. puts out.
Before I buy a rebuilt alt. I always look inside and you can tell if the diodes have been changed out buy observing one thing.........They always sandblast the alt case and diode-trio assembly. If your diodes have a sandblasted finish( grainy and not smooth) then you're getting used ones.
If your rotor and stator are good, and they usually are, you can rebuild your own GM/Ford/Mopar alternator for about $12 in parts, excluding the regulator.
Then you'll know you have new bearing, diodes and brushes.
Paul
Many rebuild shops don't change out the diodes as long as the alt. puts out.
Before I buy a rebuilt alt. I always look inside and you can tell if the diodes have been changed out buy observing one thing.........They always sandblast the alt case and diode-trio assembly. If your diodes have a sandblasted finish( grainy and not smooth) then you're getting used ones.
If your rotor and stator are good, and they usually are, you can rebuild your own GM/Ford/Mopar alternator for about $12 in parts, excluding the regulator.
Then you'll know you have new bearing, diodes and brushes.
Paul
