[oldguy]

The past: My alternator was not putting out the required voltage and had the battery light on the dash showing. I replaced the alternator with a brand new one and the battery is a new AGM.

Now currently while driving the battery light will come on and stay on, sometimes for a few minutes and as long as 15 minutes. Shutting it off and restarting the car if it stays on will shut the light off.

While the alternator was off I cleaned the terminals wires before installing the alternator.

Additionally I have checked the ground and cleaned it on the bellhousing to chassis mount. Also cleaned and checked the battery connections.

As another measure I popped a voltmeter in the lighter socket to monitor. When driving and the light pops on the voltage with the battery fully charged is between 13.1-13.5 volts.

Anybody have any thoughts? Is there an additional ground somewhere that needs checking? What am I missing?

Thanks!

 

[Jason@ Enzo`s Atlanta]

Sounds like a defective alternator....Dealer new or Ebay New??? Jason

 

[oldguy]

OEM Dealer, Scuderia Parts, New in Box

 

[Jason@ Enzo`s Atlanta]

It looks like it is charging, but the output needed to put that light out does come from the alternator itself.....sorry....Even new OE stuff can fail....Jason

 

[oldguy]

Thanks Jason


As you know its a 3-4 hour slog to do it. At least I am now practiced :-0

 

[Catmanv2]

Be worth reading the codes? Also, what does your gearbox do when the light comes on. The 6HP has a specific response to voltage issues which may help diagnosis.

As ever, though, I agree with Jason!

C

 

[DSGT]

oldguy - if you don’t mind my asking, what was the price of the new alternator from the dealer ?

These cars are too new for this to happen anytime soon, but for example on some older Porsches ( mid-90s ) the dealers sell only rebuilt alternators which have been factory certified ( whatever that means ..) they are sold as “ new “ and in the original box with Porsche label on it but they are not newly manufactured, all are rebuilt . Not that that means much, in most cases rebuilt ones are as good as brand new ones .

And as Jason pointed out you can get a brand new part which is faulty. It’s rare perhaps, but definitely possible. I’ve seen that with water pumps , alternators, and batteries .

Just wondering how many more years it’ll be until we can no longer buy brand new alternators and only rebuilt ones will be available for our cars ..?

 

[oldguy]

Be worth reading the codes? Also, what does your gearbox do when the light comes on. The 6HP has a specific response to voltage issues which may help diagnosis.

As ever, though, I agree with Jason!

C

Nothing else is affected, voltage remains good, 13.0-13.4 it's just the light pops on and off.

 

[oldguy]

oldguy - if you don’t mind my asking, what was the price of the new alternator from the dealer ?

Have to look it up

 

[Catmanv2]

Nothing else is affected, voltage remains good, 13.0-13.4 it's just the light pops on and off.

Seems unlikely that the voltage is stable, given the light is coming on and off, if you get my point.

A code read might give you a better idea, but....

C

 

[DSGT]

Nothing else is affected, voltage remains good, 13.0-13.4 it's just the light pops on and off.

Those voltage reading measurements are both taken after start up while the car is idling, or do you mean the 13.0 is the battery reading when the engine is off , and 13.4 is at idle once you start up the car ? The latter would be normal, but if it’s the first scenario I believe a 0.4 variance is a fairly significant fluctuation and maybe indicative the voltage regulator is not functioning perfectly . Just IMO based on very similar issues / symptoms I have experienced with my other car , and replacing the voltage regulator solved the problem. ( fortunately on that car the vr is removable and replaceable separately and you dont have to get a whole alternator , but I recall reading here that in our GTs , that’s an integrated part and cannot be changed separately ..? )

 

[oldguy]

The voltage when the car is running/driving is 13.0-13.4 volts when the light comes on and I glance at the voltage meter to check it. New alternator, looks like it might be the VR

 

[ErikDiSomma]

oldguy - if you don’t mind my asking, what was the price of the new alternator from the dealer ?

These cars are too new for this to happen anytime soon, but for example on some older Porsches ( mid-90s ) the dealers sell only rebuilt alternators which have been factory certified ( whatever that means ..) they are sold as “ new “ and in the original box with Porsche label on it but they are not newly manufactured, all are rebuilt . Not that that means much, in most cases rebuilt ones are as good as brand new ones .

And as Jason pointed out you can get a brand new part which is faulty. It’s rare perhaps, but definitely possible. I’ve seen that with water pumps , alternators, and batteries .

Just wondering how many more years it’ll be until we can no longer buy brand new alternators and only rebuilt ones will be available for our cars ..?

So interesting you say this!

I bought a BRAND NEW A/C compressor at Ferrari/Maserati Central Florida. Once installed, I spun the pulley/clutch and it wobbled. I pulled it off the car again to inspect it and sure enough, there was a "REBUILT" sticker from a place in UK who specializes in rebuilding. You can see there was some minor case damage underneath the silver refinishing, but you'd need to have a reason to look for it.

This was a fully sealed part in a Maserati box.

Honestly, for all the interchangeable parts (Ferrari-Maserati), I just buy from the Ferrari side. In more cases than one, I've seen higher levels of quality control from Ferrari.