Recomended Alternator troubleshooting

[timspu]

Hope all readers have had a great Christmas.
My 1988 Turbo is only charging 13.25 volts and then 12.75 volts with everything switched on. The battery is new and fully charged.
Battery earth terminal has been cleaned. I have not yet checked starter cables but the engine starts fine. I am about to rip the alternator out but just curious if this is a regulator issue or an alternator issue?
Any hints would be appreciated.

Thanks and Happy New Year to all

[Rawknees'Turbo]

That charging voltage is well within acceptable ranges for a 911 of any kind, considering the many feet of wire between the alternator and battery - in fact that is on the extremely good side of "acceptable".

Even with a new, high amp alternator, I never see charging voltage much higher than than, and often see it on the lower end of 12v at idle with all accessories on (including additional electric fans for my a/c system) and when hot. And despite that, the battery resting voltage is always 12.4-12.6, which is spot on for a 12v battery.

In other words, your numbers are perfect.

[timspu]

Thanks very much for the response, I thought it was quite low when my bike and my Ford charge at 14 volts.
Good info, will save me a large job.

Cheers

Tim

[miquel]

14.1 ok

[T77911S]

take it some place like advance, they will check the system for.........freeeeeeeee. (adam sandler voice)

[timspu]

Gents,
Just a follow up to my post. I did have the unit checked out and the voltage regulator required replacing. On inspection of the regulator it was fine, brushes had good length etc but it failed the running bench check. Bearings replaced and unit ready to re fit.
Cheers

Tim

[Ken911]

check the blue wire circuit. if the alt light bulb is burnt out it will not charge correctly. could also be a bad diode in the same circuit.

[timspu]

Gents,
Just to close out my issue, the replacement of the voltage regulator on the alternator rectified my defect.
I am now charging 14.18 volts at idle. With all electrical users energised and the indicator (turn signal) on, the tacho remains steady.

Thanks for all the inputs.

Regards

TIM

[Noah930]

Thanks for the follow-up. One of us will really appreciate it sometime in the future when we have the same problem.

[T77911S]

tiim, were you looking for headlights for a Volvo?

[Dmitry at Pelican Parts]

For anyone still looking for a guide to troubleshoot alternator issues - I've attached a DIY tech article from our site that should be quite helpful. If you still have a question or need more detailed info, please feel free to post a Comment just below the article and someone will get back to you with specifics.

Alternator Troubleshooting and Replacement


-Dmitry