86 gt 5 speed. 2 months ago i replaced the alternator as it had gone bad and would not charge my battery now today out of the blue my battery gauge is showing 18 volts and i put an ohm meter on my battery and its showing 17.89 volts. did the voltage regulator go bad on my new alternator?
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04:51 PM
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Marvin McInnis Member
Posts: 11599 From: ~ Kansas City, USA Registered: Apr 2002
Yes, most likely, and 17.9 volts can quickly kill your battery. It is possible that the alternator sense wire is open or isn't making good contact at the small multipin connector on the alternator.
How old is the battery? Did you replace it when you replaced the alternator? While rare, a bad battery can kill a good alternator. What is the voltage at the battery terminals after the car has sat overnight?
[This message has been edited by Marvin McInnis (edited 10-04-2011).]
yes i replced my battery when i replaed my alternator. i only drove with it ovecharging for a few miles i hope my battery will live. the problem just happened about 2 hours ago so ill let it sit overnight and check it but when i get home i will check and see if the 2 pin connector is loose which is possible with the way i drve lol. thans for your reply
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James Bond 007 Member
Posts: 8872 From: California.U.S.A. Registered: Dec 2002
SI alt is great for having problem w/ side plug... Can cause issues w/ sense wire.
Don't guess! get the alt bench tested before you fix anything. Over charge will cause problem for battery and everything else.
If alt is really bad, then replace or upgrade with CS130.
see my cave, alt sense in charging section.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
ok so i took the alternator back and got a new one, on the old one when it was working when i started the car it would jump to 14v then come down to 13 after driving a while...now with the new alternator it just started at 12 and now its at 10.5 so im assuming the new alternator isnt charging, i hooked up the plug and bolted the power cable up to the thing and im at a little bit of a loss.
yes the volt gauge is working and the volt light is not on. i just ran the SL test on the ogres website and with the key off im getting voltage from the S terminal and with the key on im im getting voltage from the S and I terminals. i also checked the thick red wire that connectes to the lug below the c500 plug and im getting volts on that as well.
i jumped the car and let it charge for a while when i started it and removed the cables the volt gauge went from 13 to nothing in 30 seconds so i dunno if it is the battery or what but when i started the car i heard this wierd sound coming from alternator sorta like a whine...nothing ive heard before thats for shur... is there a chance i got a bad alternator?
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sardonyx247 Member
Posts: 5032 From: Nevada, USA Registered: Jun 2003
Take the alternator to a parts store and have them test it for free. And whenever you get a new one, or starter, or ign mod., anything they can test, ALWAYS have them test the new one before you walk out of the store.
ya i just took the alternator out and ill take it in tomorrow. if i have a bad alternator that was the replacement for another bad alternator im gonna suggest they give me a different brand lol. on the bright side im becomeing an expert on alt. removal :-P
got a wierd sneaking suspistion and looked at my alternator SL port.....and the prongs were bend so the connector wasnt in there. that will definatly cause the thing not to charge.....ill reinstall tomorrow morning and try again.
