75 won't start... electrical issues.
Thread Starter
3rd Gear
Joined: Jun 2008
Posts: 3
Likes: 0
From: Denver CO
75 won't start... electrical issues.
Hi all.
I have a 75 corvette that just recently quit running. A couple weeks ago the alternator was replaced because the battery lost charge after being drivin from Albuquerque, NM to Denver, CO. A day after replacing the alternator, I took the car out and after a short distance, maybe 1/8th of a mile, the car died (lost all power) and smoke came out from the hood and through the dash. It smelled electrical, but when checked, no burnt wires or disconnections could be found anywhere under the hood or car. Right now, there is no electrical power in the car at all. I have also checked the fuse box and everything looks good.
I've been told it's possible that the alternator is putting out too high of an output. The salesman assured me that the output was the same as the original, however I'm not positive. I would appreciate any feedback or input! Thanks!
I have a 75 corvette that just recently quit running. A couple weeks ago the alternator was replaced because the battery lost charge after being drivin from Albuquerque, NM to Denver, CO. A day after replacing the alternator, I took the car out and after a short distance, maybe 1/8th of a mile, the car died (lost all power) and smoke came out from the hood and through the dash. It smelled electrical, but when checked, no burnt wires or disconnections could be found anywhere under the hood or car. Right now, there is no electrical power in the car at all. I have also checked the fuse box and everything looks good.
I've been told it's possible that the alternator is putting out too high of an output. The salesman assured me that the output was the same as the original, however I'm not positive. I would appreciate any feedback or input! Thanks!
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
The smoke you saw was probably the fusible link burning up, down by the starter.
When you installed the new alternator did you disconnect the battery first? Did you maybe accidentally spark something when it was being installed?
The alternator can put out a high voltage if the regulator is bad, but it won't over power your car unless something is drawing that power, and it gets that function from the sense wire.
You'll need to check that fusible link to see if that's what burned, and get it replaced. Check all the harnesses very carefully as it may have been under wrap.
When you installed the new alternator did you disconnect the battery first? Did you maybe accidentally spark something when it was being installed?
The alternator can put out a high voltage if the regulator is bad, but it won't over power your car unless something is drawing that power, and it gets that function from the sense wire.
You'll need to check that fusible link to see if that's what burned, and get it replaced. Check all the harnesses very carefully as it may have been under wrap.
Thread Starter
3rd Gear
Joined: Jun 2008
Posts: 3
Likes: 0
From: Denver CO
Thanks Durango boy. We took a peek under the hood but aren't sure what the fusbile link is. Would you know how to identify it? We also checked the assembly manual with no luck. By under wrap, does that mean unwrapping all of the wires?
The battery was disconnected while installing the alternator so that shouldn't have caused any problems.
Thanks a bunch!
The battery was disconnected while installing the alternator so that shouldn't have caused any problems.
Thanks a bunch!
Safety Car
Joined: Oct 2007
Posts: 4,394
Likes: 1,775
From: Seattle Area Washington
Hard to get a good shot of them,
Actually there are two, at least on my 77. Look at the 2 red wires heading down towards the starter from the plastic flex conduit. The fuse links are the white capsules right before the starter solenoid.
Actually there are two, at least on my 77. Look at the 2 red wires heading down towards the starter from the plastic flex conduit. The fuse links are the white capsules right before the starter solenoid.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Actually the white capsules are wire connectors.The fusible link is the WIRE that runs from the white caps down to the solenoid.
Pro
Joined: May 2007
Posts: 593
Likes: 0
From: Warrenville IL
Good correction DWncchs. After 30 years the spot where those connectors meet with the wire is usually very brittle also. We pulled the cables off my starter ('75 Coupe) and both wires sheared from their connectors.
NAPA sells replacable fusable link wire. Basically you need about 6-8 inches (match it up to the same length you have there already). A fusable link is a section of wire that melts and disconnects in order to protect electrical equipment like the starter. Your alternator may have put out too much current and the links melted thus disconnecting the starter to protect it.
Since I just did this on mine and have plenty of left over wire let me know if you want me to cut off a foot or two and send it to you. I'm sure we can work something cheap out.
NAPA sells replacable fusable link wire. Basically you need about 6-8 inches (match it up to the same length you have there already). A fusable link is a section of wire that melts and disconnects in order to protect electrical equipment like the starter. Your alternator may have put out too much current and the links melted thus disconnecting the starter to protect it.
Since I just did this on mine and have plenty of left over wire let me know if you want me to cut off a foot or two and send it to you. I'm sure we can work something cheap out.
Thread Starter
3rd Gear
Joined: Jun 2008
Posts: 3
Likes: 0
From: Denver CO
Got under the hood this evening and this is what we saw... they are connected but in pretty rough shape. The red wire on the left is in really rough shape and the copper wire inside is exposed in a few places (as you can see). Is it likely this wire may have grounded out? I didn't see anything that looked burned though. Could this be the cause? Thanks again.
Last edited by skizzy84; Jul 1, 2008 at 12:58 AM.
Pro
Joined: May 2007
Posts: 593
Likes: 0
From: Warrenville IL
That exposed wire requires attention period.
Since you have no power it is a very strong possibility you blew one or both of the fusable links. Check your battery for power. If you have power there, put the keys in and turn them to the 'on' position and check for power in the fuse block. If you don't have power to more than one fuse on the fuse block, you blew one or both of those fusable links. Replace them both, it is a very easy job, maybe 30 minutes of actual work if that.
Since you have no power it is a very strong possibility you blew one or both of the fusable links. Check your battery for power. If you have power there, put the keys in and turn them to the 'on' position and check for power in the fuse block. If you don't have power to more than one fuse on the fuse block, you blew one or both of those fusable links. Replace them both, it is a very easy job, maybe 30 minutes of actual work if that.
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Instructor
Joined: Jan 2005
Posts: 172
Likes: 2
From: Cumming GA
I had a very similar situation occur on my 82 not long ago. Check the ring terminal with the large red (battery) wire on the back of the alternator. The one on my alternator had been over tightened or not tightened correctly, and allowed the connector and stud to short against the case of the alternator. Smoke big time for about 5 seconds until the fusible link blew. Because you just had your alternator replaced, it could be a similar problem. Hope this helps.
Andy
Andy