Battery/alternator question

BLDUN

MEMBER
CHEVROLET

Here we go. I bought a new chrome alternator for my '94 Z28 camaro. It began charging as expected at about 14 volts. Then drifted down to about 9.5 - 10.5 and would not come back up. Sent it back and they said they bench tested it and it was OK. When I put it back in the battery was dead so I jumped it. - Wrong thing to do - I took it to a local alternator shop that rebuilt it and tested it at 14. Put it in with batter fully charged and all I get is the same reading. Put brand new optima battery in - same thing; had my old alternator rebuilt today; put it in and same thing. Single wire that plugs into alternator is reading about 11.6 volts with key on. Battery reads about 12.6 across the connections. When car is running I can only get about 10.8 coming from the alternator. I have huge ground wires and have regroudned it 4 times. Any ideas where to go next?

2 Replies

SLAR69

MEMBER
5 POSTS

Sounds like the wire to the alternater on top is not exciting the field. Alternaters need current to begin charging. Check your voltage at the two wire plug. One should have 12.6 volts.

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Friday, December 22nd, 2006 AT 3:09 PM

BLDUN

MEMBER
2 POSTS

There is no 2 wire plug on a '94 Camaro. It is a one wire plug and according to the Helms manual should read close to the battery voltage. With the key on I get about 12.3 on the battery and about 11.6 on the single wire. Don't know if that's enough difference to cause the problem or not. I spoke with the alternator guy today and he said 11 volts should be enough to kick it in.
Also, I thought like you that maybe it needed more juice to I made a jump wire and tapped into a slot in the fuse box that is hot when the key is on and is reading battery voltage and then connected it to the alternator but still no help.