Altenator Problem-Help and Advice
Thread Starter
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
Altenator Problem-Help and Advice
I just got in from 100* heat, jumping the car, and getting it home. I loaned my 1989 Coupe to my girlfriend to go shopping which turned out to be a huge mistake. She called from an entrance ramp on I-40 in a town 40 miles away, of course, and said it died and won't start.
I jumped and started it and the dash volt readout was 11.4v and dropping. So I figure alternator bit the dust. I drove quickly to Aotozone which was just closing and they check and verified the 11.4 and it dropped to 10.7v during his test on the car.
So I figure I'm running on battery only. I decide to charge it a while and try to make it home 40 miles. So all electricals shut down here I go.
About half way home the engine stutters very briefly and the dash read out jumps to 13.0v and holds! Long story short, I made it home O. K. and am typing and drinking a cold beer.
What do you think I should look for? I've only had the car a month and it has been running great. Could it just be a bad connection to the altenator?
I jumped and started it and the dash volt readout was 11.4v and dropping. So I figure alternator bit the dust. I drove quickly to Aotozone which was just closing and they check and verified the 11.4 and it dropped to 10.7v during his test on the car.
So I figure I'm running on battery only. I decide to charge it a while and try to make it home 40 miles. So all electricals shut down here I go.
About half way home the engine stutters very briefly and the dash read out jumps to 13.0v and holds! Long story short, I made it home O. K. and am typing and drinking a cold beer.
What do you think I should look for? I've only had the car a month and it has been running great. Could it just be a bad connection to the altenator?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
It could be a poor connection from alternator to the battery. Check the resistance from alternator output to the positive terminal on the battery, it should be the same as touching the ohmeter probes together. If any resistance shows, it could be a damaged fusible link in the alternator output wire. You should have noticed the red battery symbol light on the dash lit showing that the alternator was not charging the battery. It also is fairly common to find a broken connection inside the alternator to the output bolt and yours may have made connection on the way home. Another explanation is worn out brushes that no longer allow field current that got bumped enough on the way home to make connection to the slip rings. Any dash voltmeter reading in the 12's, then you are running only on the battery. Unplug the connector on the alternator and look at the condition of the contacts and spray with electrical contact cleaner if they aren't bright.
Last edited by jfb; Jul 1, 2006 at 07:26 PM.
Thread Starter
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
Yes, I did see the battery light on the dash. After the engine stuttered, and the output jumped to 13.0v on the dash, the light went out. I bought one of those "lifetime" reman. alternators from AZ just in case. This kind of stuff always seems to happen on a holiday when you can't get parts.
Thread Starter
Le Mans Master
Joined: Jun 2006
Posts: 5,642
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From: One day you're a Comet...the next day you're dust... Arkansas
I think you are right. The alternator in the car is OEM original. I bought an AZ today so I would have it if I need it. Thanks for the input! Basically I will check and clean all the connections and if I can't get the output up to spec I will replace.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Time to pull the alternator, I bought one of the new alternators at AZ, don't care for the rebuilt vs new cost, not that much difference in price. Once I was having a conversation with Gordon Killebrew and he told me running on a bad alternator can also cause damage to our digi dashes. Of course you've checked to make sure your battery terminals are clean and tight?
Just saw your response to another thread, I don't think the Duralast Gold is a rebuilt is it?
Just saw your response to another thread, I don't think the Duralast Gold is a rebuilt is it?
Last edited by rick lambert; Jul 2, 2006 at 10:14 AM.
Thread Starter
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
No, it is NEW. I thought I was buying a reman. for $110. The thing carries a lifetime warranty and is new! Hard to believe, but I'm looking at it as I type. Go figure!
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Thread Starter
Le Mans Master
Joined: Jun 2006
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From: One day you're a Comet...the next day you're dust... Arkansas
Well the saga continues. I went out this morning after slow charging the battery over night. I cleaned and tightened all the connectors and cables I can reach. I started the car and the dash readout climbed from 13.5v to 14.1v. and held. This is after the final readout yesterday being 13.0v.
What do you guys think? Just a bad connection? Should I ride around for a while with the new alternater in the back of the car?
What do you guys think? Just a bad connection? Should I ride around for a while with the new alternater in the back of the car?
Team Owner
Joined: Jun 2005
Posts: 46,295
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From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
Well, 14.1 isn't bad at all. Maybe do some trips right around the house, nearby. Then if things hold, go for a little longer, straight line trip where you know if things go bad, you've got plenty of places to pull over and park. And of course, stay in the left lane so you don't have to pull a maneuver in traffic with failing/failed power. Don't do this at night.
Thread Starter
Le Mans Master
Joined: Jun 2006
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From: One day you're a Comet...the next day you're dust... Arkansas
O. K. that's a plan. The 14.1 was at idle so it will be interesting to see what happens on the road. It may get up to the 14.5 it was reading last week.
Drifting
Joined: May 2005
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From: Chicago Executive Airport, formerly known as Palwaukee
No-IL Events Coordinator
St. Jude Donor '12-'13-'14-'15-'16-'17
Did you follow all the cables coming off the positive end of the battery? You might find two smaller cables that go to junction blocks. Take those apart and clean all the eyelets.
Also, take the cables off the starter when you have a chance. Cleaning the starter connections will keep your starter zininging like it should!
SAVE THE WAVE!
Also, take the cables off the starter when you have a chance. Cleaning the starter connections will keep your starter zininging like it should!
SAVE THE WAVE!