Smoked another Alternator

[Vince13]

It seems to be the spring of electrical gremlins. The original alternator gave out 3 weeks ago, I figured it was due as it still looked like the original one. I replaced it with a Napa 140 amp and drove the car a couple times a week with no problems 13.5 - 14 volts worked good.

Today I notice the volt gauge dropping under 12 volts and pull over and pop the hood and c an see the smoke coming out of the alt and the case too hot to touch. I checked the positive cable and all looks good it is tight and does not look like it is touching the frame or block. The fuel pump hot wire has a 30 amp fuse and it is not blowing same with the dual fans. Before I disturbed anything I disconnected the negative and checked the resistance of all the connections at the back of the alt to see if I had a short to the frame and everything checked out ok.

Any ideas ?

 

[Ktbregal]

Very interested my alternator gets really also.

 

[turbofabricator]

New alt and check amperage draw. Wire in an amp gauge between the output terminal and all the wires that hook to the hot terminal of the alt. Might just be a poor rebuild.

 

[scgnx2]

Bring it back to Napa and have them test it. They have a pretty good warrant policy.

 

[Vince13]

I am going to give that a try, where can I find cheap ammeter?

 

[Vince13]

Update
I pulled the positive cable out checking for rub through or potential shorts, I checked all the fusible links for the same following them all the way up behind the head and into the harness. All looked good, no chafes or rub through. I replaced the alternator to battery charge wire to a heavier gauge and replaced the eyelets for the hot wired fuel pump and dual fans. They were pretty toasty from the last time the alt overheated.

Napa replaced my 140 amp Impala SS alternator under warranty and I got that installed.

I had access to an AVR machine and everything checked out fine. At idle with the fans on, headlights on high and defroster fan on full it was pulling 28 amps according to the AVR machine. Brake torqued the motor to see if anything was touching in that situation and no change.

Load tested the alt and it easily put out 120 amps and the battery checked out fine also. Voltage drop on the negative cable was .002 volts.

The car runs good, let's see how long that alt lasts. My mechanic friend said it is a crap shoot with the rebuilds having to change it twice is not uncommon.

Time will tell.

 

[TurboBuRick]

Running a volt booster?

 

[Vince13]

No volt booster.

 

[Phoneguy]

I just had a 3 week old alternator start dropping voltage at high rpms. Luckily I was able to see it in my XFI logs. Dropped to 10.5 volts
Try explaining that to a counter guy at Autozone. ..
He said if it passes on my tester then I can't warranty it.
One of the managers has seen me in there for years and knows my car, he finally stepped in and told the guy to cover it.

Bryan

 

[NY_GN]

Do you have the caspers ALT field fix? Had the same problem, went thru 3 alternators until I got the field fix. Now I've had the same alternator for 4 years, no issues. Well worth it.