Fried my rebuilt alt.

[dweymer]

So I finally got around to getting a rebuilt alt; installed it on moving day, and promptly fried it. I charged the battery before install and it showed 12.65v before install. So what else could do this? Which wires should I chase first? If I recall correctly the isolation and exciter diodes on the old one were done, so I am thinking wire to the charge light, anybody....

Thanks

[RoninLB]

Originally posted by dweymer


and promptly fried it.

hooking ground and positive in reverse will fry it.

[dweymer]

It was installed per workshop manual. I don't have it here in front of me, but I double checked that before it went in.

[RoninLB]

so you didn't blow diodes? It's just not charging? Did you also replace the external regulator as is usually recommended?

[john walker's workshop]

a burnt out dash (battery) light will keep it from charging. how do you know it's fried?

[ruf-porsche]

I gave that same respond to another Pelicanite with alternator problems. Check da light bulb.

When the magic smoke comes out of the alternator that a good indication that it is fried. The other indication is a strong odor of burnt insulation.

[dweymer]

Ok, I don't know for sure it's fried I am just jumping to conclusions because that is how it has been here lately! I installed the rebuilt alt, turned the key, (dash light on); cranked and started, light went out, revved to around 3k, light flickered then stayed on. I have not had a chance to pull out the rebuilt alt, but I am guessing whatever destroyed the first one was not fixed. The car had this issue when I bought it. No like a jacka$$ I did not also replace the regulator, nor check all the wiring in and out for shorts. I did check the wiring inside the shroud and it all seemed ok.

[RoninLB]

Originally posted by dweymer
, light flickered then stayed on.

No like a jacka$$ I did not also replace the regulator,

I did check the wiring inside the shroud and it all seemed ok.

bypassing the regulator into a "full field" can be tricky with the CDI, although I would hook up a switched on/off if I was trapped somewhere. It's not needed here anyway imo.

wild guess is that you you need a regulator or a spare reg in the trunk to proceed further. Some guys have reported prob's with the solid state external reg's so get the simple mechanical one.

[dweymer]

ohh goody, more shopping...lol. Ronin, I will get my car back sometime this week and check the alt. Would it be easier to upgrade the alt to the later style with internal reg? (assuming mines fried again). Mechanical reg is what is here on PP right?

[RoninLB]

Originally posted by dweymer
Would it be easier to upgrade the alt to the later style with internal reg?

Mechanical reg is what is here on PP right?

the external regulator is what many track guys suggest due to claimed internal regulator failures from excess heat. I installed an internal regulator Valeo and have never had an issue with this on a street 911. afaik the internal reg is operational till it's 210degF. Operation at 220degF is a maybe. I also brought in a 50k mi Valeo for testing entertainment and it reached the claimed 90amps and held that for a couple of minutes till I said to the tech "good enough". My car came stock with an external reg.

There may also be a regulator "noise suppressor" installed into the external reg sitting close by. REMOVE IT. This suppressor can cause operational prob's.

I can't comment on the PP external reg. Call them.

Some guys have had problems with the solid state regulators. Get the mechanical operating reg. The only solid state regulators I have confidence in currently are expensive marine units.

when you say "fried" it makes me think of actual smoke from the winding's bakelite/whatever insulation. Some members call it the magic smoke that escapes leaving a "fried" unit.

[dweymer]

couldn't see the magic leave the unit from drivers seat, but I will check it when I get her to Orlando; and update the thread. Thanks