Charging system

[DSMDREAMER]

I have a problem with a 93TSI.
This is what I have done so far,
I have replaced the alternator at least 5 times(advance) it always passes the bench test I have also replaced the relay and all related buss fusses, and the battery(twice).
This is the problem if I disconnect the alternator lead at the battery and start the car I get 14.5v, as soon as I put it on the battery it drops to battery voltage. . I have checked everything for resistant and my connections are good. Does anybody know what the voltage readings would be on the plug that connects to the back of the alternator.(not the b+). also, after the voltage drops to the battery, if I disconnect the alternator cable it does not go back to 14.5v until vehicle is restarted. ( I know thats a no no but I am frustrated.) please HELP!! If you need any more info please post away

 

[super97gst]

voltage coming out of the alternator should be 13.8volts. it sounds like you have a ground somewhere in the system. not a full blown ground that would cause everything to completely ground, but an intermittent ground. these are rare but it does happen. my advice would be to start pulling cables off at each end and checking complete continuity. if you cant find the problem this way let me us know and i will try to figure something else out.

edit: also, you might want to check where each cable/wire grounds to the car. check for corrosion or loose cables.

 

[DSMDREAMER]

Thank you for your reply. I have removed all wires that have anything to do with the alternator. I also replaced the B+ cable. I have no resistance. I also check voltage at the plug that goes to the alternator and one is a 12v and the other is supposed to go thru relay, fuse, and a indicator lamp. Do you know where I could test that circuit or which fuse it is. I am wondering if I have a short there, since I have triple check everything else. I also do not have the cover to the fuse panel so a reference would be greatly appreciate it. again thank you for your help.

 

[super97gst]

Thank you for your reply. I have removed all wires that have anything to do with the alternator. I also replaced the B+ cable. I have no resistance. I also check voltage at the plug that goes to the alternator and one is a 12v and the other is supposed to go thru relay, fuse, and a indicator lamp. Do you know where I could test that circuit or which fuse it is. I am wondering if I have a short there, since I have triple check everything else. I also do not have the cover to the fuse panel so a reference would be greatly appreciate it. again thank you for your help.

you could test it at the fuse block, but since you dont have the cover that might pose a problem. i dont know where each fuse is located on a 1g. you could chase the wires back from the plug back to the fuse box, the one located in the engine compartment, but that will be pretty hard to do since it's all covered in shrink wrapping.

try pulling the relays out of the fuse box first. take each relay and test continuity between 85 and 87. if that shows nothing then the only thing left to do is start chasing wires. i know it will be a very time consuming job. just cut all the heat shrink off and when you get done chasing just cover back in wire loom or some more heat shrink if you've got some.

thats about all i can think of right now. i hope that is enough to get your car going.

edit: you might also want to post a new thread asking the location of all charging system fuses and relays inside the fuse box.

 

[TURFNNSURF]

DSMDREAMER,

Here this link may help you out. its a picture of the fuse block cover for the interior fuse panel. Hope it helps some. I think i read somewhere that if the indicator lamp burns out it could cause a problem like what you are experiencing.

http://www.dsmtuners.com/forums/attachment.php?attachmentid=19902