I have two variables for this situation.

A couple days ago I jumped someone else’s vehicle with mine. Long story short I really didn’t want to but he wouldn’t leave me alone.

Following this I replaced my belt with an 85” Gates. Technically 85” 5/8 long. I found this recommended by forum members in old threads, a previous owner had ripped off the smog pump and threw it out I guess. So my stock belt was practically touching itself. The new Gates was a proper replacement and was still able to be tensioned. It is obviously much tighter.

I noticed on the way home my volts were low. 11.6-11.8 with the lights on. Today in the daylight I got as high as 12.8. Prior to these two occurrences with the vehicle I always held 14.4v. So it is somewhat charging but just barely hanging on. I see no bad fusible links.

Thoughts? Did I cost myself $160 by jumping someone’s vehicle? Or is a way tighter belt on an old alternator somehow a problem?

 

First, Welcome to the Corvette Forum RedAnt1984!

I would start by charging the battery up completely First. Then clean both connectors and the posts they attach to with a wire brush. Take the battery and go someplace where they will test it for you if you can. With a charged battery it will do better on the test...

Did the other car start "okay" when you jumped it? Did anything unusual happen while you were jumping it? If the engines were left running while the batteries were connected to each other you might have damaged your alternator. Never leave two batteries with different chargers connected to each other. When you jumped the other car where did you jump it from? Battery to battery or what?

When you car has the battery in it does it ever go above 13 volts anymore charging with the alternator in question?

Try and measure the output of the alternator in the Alternating Current (AC) Mode. IF there is any significant AC coming out of the alternator then your bridge diodes might have been toasted.

NEVER run a alternator with nothing plugged into it. Never unplug one while it is running either for that matter.

 

I would check voltage at the battery post too... Just to be sure. My dash reads somewhat lower than battery voltage. Otherwise, I would start checking what is listed above. Mine would sometimes work before I rebuilt it but a couple hard pulls above 4k would usually get it working again. I ended up rebuilding it with a new voltage regulator and it was fine after. hope it is something simple.

 

If you can get a 'carbon pile' test done on the electrical system with alternator in place it would be I'd think best advice. At the same time confirm battery condition, condition of the terminations to both battery terminals, the ground to frame rail etc.

An 'on the car' carbon pile device would be the BEST evaluation of the entire electrical.

 

Good advice above. With nothing electrical on except the engine, can you get to 14V at 1-2K RPM? If not, I'd have your alternator tested. Sounds like the culprit. If yes, then I would suspect your new belt is slipping when the alternator is under load. Generally, unless you accidently cross the polarity, jump starting shouldn't hurt anything.

 

Hey guys,
Well unfortunately this has been resolved. $130 for an alternator from O'Reillys. Checked everything over with the meter I have, the car did come with a new NAPA battery so I at least had that going for me. On a side note, the 'Ultima' brand alternator fit good and worked good. The only note on it is the top mounting hole was not threaded, so I had to go buy a longer bolt and a nut. I will be replacing my battery bolts since they are old and oxidized.

I did jump the cars from battery to battery. Years ago I never had any issues doing this on Volvos (only brand I owned for 7 years) and occasionally with our Chevy 'Park Truck' when campers killed their batteries running lights and whatever. That being said, for a decade I had a nice Die Hard jump pack because I still preferred not to use my actual car for fear one time something like this would happen. In the past with real dead cars I would leave the cables hooked up for a minute after because a couple times we pulled them off right away and the car being 'saved' would stall out. I honestly thought being my car is so old there wouldn't really be anything to get damaged, didn't think for a second it would take out my 120amp alternator. I don't think the other guys POS even needed a jump, it had loose battery terminals and started just fine. They likely got wiggled in place just hooking up the cables.

It is what it is. Lesson learned.

 

When I upgraded my car to a cs130 the hole also wasn't threaded so I just used a helicoil in it.

Anyway chances are it was already on its way out and the jump put the nail in the coffin. If it were the original alternator chances are it was just the regulator. The replacement parts are like 20$ and it takes maybe 45 minutes to test everything and double check but sometimes I just say screw it and put a new part in too because I'm tired of doing things like that. Glad it's fixed and was simple.