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Old 05-11-03, 06:31 PM
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Unhappy Alternator problem

Just a few days ago i bought a 91 convertable rx-7 in excellent shape with 100,000 miles for 400 dollars. The original owner was tired of the alternator burning up and basically gave the car away. He put a new alternator on the car and before he got home that night it droped from 14 volts to 11 volts. (basically it quit charging) I have performed the test to check for a short in the system and it showed i had a short. I pulled all the fuses one at a time to see if i could find the curcuit that was shorted and none of them indicated any type of problem. I have removed all of the after market neon lights and other junk he had installed. I am completely stumped now. I have heard of the fuseable link going bad and doing the same thing. I have searched for the link and cant find it. The Haynes manual tells you where to look and also says "if equipped". Can anyone offer some help or tell me if the 91 convertables had fuseable links? Any information is greatly appreciated.
Old 05-11-03, 06:38 PM
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NEON lights??? damn good job taking them off. Try looking at the FSM it is probably better than the Haynes. www.fc3s.org or www.iluvmyrx7.com have them on-line.
Old 05-12-03, 02:34 PM
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You are doing it right. Be patient if it's intermittant.

To cook an alternator that quick without burning a shorted wire somewhere says it's well upstream, near (or in) the battery or near the main fuse block.
Old 05-12-03, 09:04 PM
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make sure theres not a bad cell in the battery, most places check it for free.Also start the car and unplug the pos side of the battery if the car still runs it may not be your alternator
Old 05-12-03, 09:22 PM
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Originally posted by SureShot
To cook an alternator that quick without burning a shorted wire somewhere says it's well upstream, near (or in) the battery or near the main fuse block.
I went through this not too long ago. I was toasting alternators left and right. The battery was shorted and couldn't hold a charge so the alternator was having to work that much more harder. You should take your battery and get it tested to see if it can hold a charge. Even though the battery reads 12volts, it can still be shorted.
Old 05-12-03, 11:58 PM
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Ill have the battery tested but it is a pretty new red top optima. I wouldnt think it would go bad this soon but anything is possable. I checked the output of the alternator and it is only showing like 12volts. It should read 14 to 14.5 volts. I am still researching the fuseable link idea. Does any one have any comments on the fuseable link. The haynes manual says it is located between the alternator and the strarter selonoid. But where?????? The manual says it will act the same way if it goes bad. I am looking into the fsm manual tonight to see what it says. I performed the check where you use a test light on the negative post and the negative cable and shows i have a short. I pulled all the fuses individually and the light never went out. This leaves me to beleive the short is before the fuse box. Can someone comment on this tell me if i need to do something different. Thanks for all the comment and help so far. It is all very usefull
Old 05-13-03, 12:59 AM
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Originally posted by 1987RX7guy
NEON lights??? damn good job taking them off. Try looking at the FSM it is probably better than the Haynes. www.fc3s.org or www.iluvmyrx7.com have them on-line.
SEE?!??! Whats wrong with NEON LIGHTS?
Old 05-13-03, 07:38 AM
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Originally posted by 91 rotary
I checked the output of the alternator and it is only showing like 12volts. It should read 14 to 14.5 volts.
Oops - cooked another one.
Aint warranty's great..
Old 05-14-03, 11:19 PM
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Alright heres the deal. I had the battery tested when i went to get the new alternator. The test said to recharge and test again. The guy told me it was probably good. Soooooooo i went and put the alternator on and started the car. When i disconnected the negative from the battery the cars idle jumped up. So i tested the alternator. A strong 14.7 volts. When i reconnected the battery it dropped to 12.2 volts. So i went to autozone and baught a Duralast (just a cheap regular battery) When i put the new battery in, the car tested (while running) 14.5 volts at the alternator and battery. I drove the car for about an hour or so and it never dropped. I hope this can be of some useful information. I know i wouldnt buy another red top optima for any of my vehicles. The red top is just a starting sereis battery any ways it is not designed to be drained fully and recharged multiple times. This one was and i beleive it killed it. Any way, so far the car is running great and thanks for all the advice !!!!!!!!!!!!!
Old 05-15-03, 11:13 PM
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Speaking of Optima Redtop, can they be recharged with a regular battery charger?.. I bought mine with a very low charge and when i went to autozone to get it recharged they used a slow charger and it never charged.
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