I got a project car a couple months back and I’ve been slowly working on the things that I know are issues.

Right now, the alternator is baffling me.

For context, I have fixed from a non-working state:

• Headlights
• High beams
• Hazard lights
• Daytime running lights
• Windshield wipers
• Brake lights
• Distributor
• Starter solenoid
• Alrernator
• Several spark plug wires, and insulation sleeves
• All spark plugs
• Temperature sender
• Water temperature gauge
• Battery (with remote disconnect)
• Water pump
• Thermostat
• Door latches, locking mechanisms, window alignment

in addition to all this, checked or repaired the entire vacuum system. Also, Engine was running way too rich/flooding, but is good now.

So this is the problem:
After about 50 miles of owning the car, the alternator died in some stop and go traffic. I realized there was a problem and the battery died, and I pulled over to inspect the cause. I tried to jump it, and the alternator started smoking. I know alternators can’t smoke if they are shorted or if the diodes are bad or cooked or whatever.
So I replaced the alternator. Well after less than 20 miles, the car started stuttering at idle— I turned it off, opened the hood and saw the new alternator smoking. So it appears that the same thing has happened again. Something is cooking my alternator, and I don’t know what to check because I don’t totally understand what variables and nuances can affect the charging system.

I did notice the two wire connection to the alternator is brittle and loose, and I have a replacement to change it with.

So I guess my question is what kind of things could make the alternator fry multiple times? Brand new battery, grounds in the car are decent! Very little corrosion or rust anywhere! The car still needs a lot of electric work (radio doesn’t work, none of the convenience lights are hooked up, none of the sensors for stuff like door, ajar, parking brake, key in ignition— none of that stuff is functioning right now)

One friend told me my first replacement alternator was a low quality one even though it was one of the more expensive ones I could find quickly for this year.

Any ideas what I can look for? I’m not looking forward to frying any more alternators and possibly doing damage to the electrical system in other places because of it.

 

Replace Both + POS and - NEG battery cables. AND thoroughly clean - NEG cable Ground Point on chassis near battery.
Battery Cables DO corrode Inside-beneath insulation; 'hidden' cancer. They're relatively cheap to purchase but that Long Positive cable is a chore to R&R (through tunnel & above trans).

 

Possible causes, high output alternator installed without upgrading wiring. Possible wiring incorrect at the 2 wire plug.
My best suggestion to you is to go to Mad electricals Web site. Go to there tech pages. Read the articles about the differences in 1 and 3 wire alternators. Read the article about upgrading the wiring for a higher output alternator.
You'll find the articles are written for the novice. Like automotive wiring for dummys.
madelectrical.com

 

per your profile; this car has MSD Ignition. Perhaps something amiss within or in how it's wired into your vehicle. OR, not related to charging issues at all.

Dunno which or how many MSD you may have (there are Many)
Suggest you download MSD instructions (with install-wiring diagrams) for each MSD device you're running.
Unless you're an EE or ET, suggest use MSD diagrams to help you verify all your MSD devices are installed per MSD specs.

 

You stated the 2 wire connection is in bad shape. That connector goes to the voltage regulator. Without the regulator knowing the alternator output the voltage will spike burning out the alternator.

 

I will look this up and read up! Thanks for the helpful reply.

 

So I replaced the connector and it definitely seats more solidly than before. Although I haven’t put many miles on this thing since the alternator was swapped, momentary loss of voltage regulation burning up the alternator makes sense I think.

 

I honestly assumed since the last owner redid the ignition, it was in good shape— as in not the first thing that I would check since everything looks new. I can see how that could be a bad assumption.

as far as what it has MSD:

• digital 6a ignition control
• corvette v8 tach drive distributor w/vacuum advance
• Blaster 2 red ignition coil

I will be reviewing the wiring diagrams and figure out if this stuff is up to par soon as well. great suggestion!!

 

Did you test the alternator output with a voltmeter?

 

First, NOT suggesting that MSD TD distributor itself is contributing to charging failures. But the following is simply a head-up on special conditions.
Sadly, MSD TD distributors (as well as some other MSD dist) have a history of gross corrosion of metal parts under cap and inside dist bowl (housing). Not all have the corrosion problems, but many do. It'll be worth your while to periodically pull cap and closely inspect throughout dist for signs of corrosion. It seems that venting the dist helps to prevent/minimize that corrosion. There are vented marine-grade caps available. Also, the bowl/housing can be vertically drilled for 1 or 2 small vents (some later GM dist have OE bowl vents). It's a mystery to me how and why some guys have MSD dist corrosion issues while others have none at all. Well-established fact that all distributors make a fireworks show under the cap; and those sparks ionize any humid air to produce an acidic, corrosive environment. Again, this NOT to suggest your distributor itself is causing charging failures.

 

Very good to know! I will take a look soon at this!

 

I just swapped out the new alternator, and once I get it running, then I will test voltage out. shouldn’t be too much longer.

 

When you get a chance show us some pictures of your connections at the alternator.

 

^^^^this^^^^