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-   -   Alternator/voltage help (http://forums.pelicanparts.com/porsche-911-technical-forum/967824-alternator-voltage-help.html)

shaunmbenson 08-25-2017 06:42 PM

Alternator/voltage help
 
So i have a refurb alternator that was installed about 9k miles ago and battery 11k ago

On drive home tonight seatbelt light would flick on and at stop light after hour drive the alt loght cane on briefly and flickered out

The batter voltage is 13.34 with car off and 15.54 at idle

Why would these numbers be too high and more inportantly - since mechanics all away for weekend

CAN I TRACK HER TOMORROW!!!

manbridge 74 08-25-2017 07:11 PM

Voltage regulator is likely dying. You can track it if you leave all your consumers on and voltage doesn't climb much above 15.5v. Ie, lights, AC, blower motor etc. Monitor voltage through cig lighter and tread carefully...

shaunmbenson 08-25-2017 07:17 PM

Thanks Manbridge
I think given your advice and a few other friends I will not track tomorrow - treading carefully around mosport is not fun and I've already trailered from there once when I didn't heed CHT sensor failing indicators.
Appreciate your input

86 911 Targa 08-26-2017 09:36 AM

Voltage regulator.
 
Please replace asap before other devices such as your battery fail.

Your VR should charge around 13.5/14.2 volts.

Good luck.

adias 08-26-2017 10:40 AM

I agree. VR is bad.

grizzfan 08-26-2017 10:57 AM

I don't think I'll ever live long enough to find happiness with the alternator - battery - voltage regulator lash up in these cars. (And they talk about the "triangle of death" for oil leaks!!!)

While the VR may turn out to be the culprit, IF that doesn't solve your problem it could be the diodes in the alternator that have failed (most rebuilders will honor another rebuild within one year) or a bunch of other things to include the grounding strap or insulation of some of the alternator innards.

I've found that replacing the VR is a challenge too. Your car might be new enough so that the VR part number is a valid fix. However the original alternator rebuild may have changed enough components to make that problematic too. I have experienced all of these problems.

I don't want to scare you to death, but once these symptoms start you are probably going to have more "fun" than you bargained for.

Good luck.

Tom

adias 08-26-2017 11:32 AM

The diodes most likely. I thought that the rectifier bridge was inside the VR. Apparently not.

And of course the major hurdle here is to access the alternator. - a major, tight space, working job.

darrin 08-26-2017 11:50 AM

sounds like the OP has a 3.2 carrera (head temp sensor), for future reference, the voltage spikes from a failing vr can also take out your tach and fry electronics (DME computer) -- best to avoid driving until fixed

93nav 08-27-2017 09:06 PM

As someone else suggested, get one of the volt meters that plug into the cigarette lighter socket. I had/have one of those, it was showing readings from 11 to over 17, replaced the VR (external), and all was good.

T77911S 08-28-2017 03:20 AM

is your MM a good one?

get a small (new) 9v battery and check the voltage to make sure your MM is working.
at 13.34 the battery could be bad. I think its called internal battery sulfation.

take the car to advance, they will check the charging system for FREEEEEE!


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