Question about alternator backfeed correction...
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Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
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Question about alternator backfeed correction...
Fixed the alternator backfeed , that kept the engine running even though you turned the key to the "off" position, by putting a diode on the hot wire to the ignition box. It works perfectly now.
Apparently the diode keeps the electrical current going in one direction, preventing alternator backfeed.....my question is this....Is this diode "masking" a bigger problem with the electrical system OR is it the correct fix for alternator backfeed? My mechanic (who has been working on Corvette since I owned it in 2001), tested & checked every wire, connector and function that dealt with the ignition. and everything checkout OK. I've had it a week and I, too, have put it through the ringer and everything has worked perfectly. I'm just concerned because the original problem (ignition wire from the alternator burned, see my previous post) happened without any warning or symptoms.
Any thoughts will be appreciatated!
Apparently the diode keeps the electrical current going in one direction, preventing alternator backfeed.....my question is this....Is this diode "masking" a bigger problem with the electrical system OR is it the correct fix for alternator backfeed? My mechanic (who has been working on Corvette since I owned it in 2001), tested & checked every wire, connector and function that dealt with the ignition. and everything checkout OK. I've had it a week and I, too, have put it through the ringer and everything has worked perfectly. I'm just concerned because the original problem (ignition wire from the alternator burned, see my previous post) happened without any warning or symptoms.
Any thoughts will be appreciatated!
Safety Car
Joined: Sep 2012
Posts: 4,688
Likes: 41
From: Palm Harbor, Florida
if that fixed it, and your mechanic did what you said. now when the car starts up on its own, then you really got problems worth exploring, but then you'll need an exorcist and not a mechanic
Advanced
Joined: Nov 2006
Posts: 89
Likes: 0
From: angola new york
alternator feedback
you have a bad diode (diode trio) in your alternator which will feedback through your wiring until your battery is dead.
remember,if the factory didn't install it,even after a "recall" it doesn"t need it. A diode in the wiring harness is a fix, but not the right fix.
in fact i literally just rebuilt my alternator for the exact same thing on my 73 camaro.
it's a very inexspensive fix.
remember,if the factory didn't install it,even after a "recall" it doesn"t need it. A diode in the wiring harness is a fix, but not the right fix.
in fact i literally just rebuilt my alternator for the exact same thing on my 73 camaro.
it's a very inexspensive fix.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
The wire to the alternator should come from the accessory side of the ignition. The reason is that when the key is off, the ign and acc circuits are separated and the alternator cannot feed the ignition. Once the engine has been started and the alternator excites and begins to charge, it produces voltage at the small plug, brown/white wire, and continues to have this voltage till the alternator stops turning. So to cure the run on problem, make sure the wires in the alternator plug are oriented correctly or you will have the same issue, or make sure that the alternator small wire(brown/ white) has power when the key is on accessory and when on. If it only has power when the key is on and not when turned to acc, then you will know its not on the accessory circuit as it should be. In short, no need for a diode if its wired up correctly.
77 and later cars with a gen or alt light are wired differently so the same test does not apply to them, they have the brown wire wired through the gauge fuse via the gen lite which will not allow sufficient current to cause the run on.
77 and later cars with a gen or alt light are wired differently so the same test does not apply to them, they have the brown wire wired through the gauge fuse via the gen lite which will not allow sufficient current to cause the run on.
