Next time you have the undertray off....

I just had a minor incident that could have had major consequences. I was driving back from a local car event and just as I was getting close to my house I smelled something burning. I looked in my rear view mirror and the engine compartment was lightly filling with smoke. I immediately pulled over and grabbed the fire extinguisher but fortunately there were no flames and the smoke immediately stopped. Once we got it up on the lift and took the under tray off we found the large wire coming out of the back of the alternator had started to burn (sorry I spaced and didn't take any pics). Upon further inspection we could see that corrosion had built up inside the wire causing resistance which turned into heat which would not have ended well had we not caught it so early. Interesting thing is the car has very rarely been in any kind of elements and kept in a garage. The good news is the damage seems to be limited to the alternator wire and it took the battery with it but no other systems seem to have been impacted. New wire and new battery and the car is back to its fun self.

Just a word of advice that the next time your car is up on the lift and you have the undertray off for any type of oil service, etc. take a good hard look at that wire. It wasn't readily apparent unless you could see the bulge in the wiring. Had that same thing happened when the car was at speed it would have very likely turned into a true fire and you can imagine what can happen from there.

I hope this was just a very unique incident but thought it was worth sharing with the community just in case.

 

Thanks for sharing. Which wire?

 

Yes this a known flaw in the alternator cable. It's 2,200 usd to buy the replacement and about 800 to put it in (dealer prices). You may get lucky as I did and just crimp on a new unburnt end and add the extra heat shielding that should have been there in the first place. Good catch OP, you saved your ride from some extra downtime by finding it!

EDIT: anyone doing a PPI should have this checked and photographed. The suspect area is where it attaches to the alternator.

 

I don't agree it is a flaw in the cable. It is big enough gage to handle normal load. The only cars I have seen those be an issue is where the cable connections are compromised and there is high resistance causing too much heat and load or there is a problem causing the alternator to work at very high output levels constantly. All are known problems and the cable and often the alternator itself failing are just symptoms of the real problem. Cars with properly functioning and properly maintained systems never have the problem.

 

Wasn't there a later cable that has different end config?
My car was a garage queen with bone stock electrics. <9K miles and mine was shot. I thought that when I researched it the later cable had a nice rubber boot at the end and more robust heat shielding which lead me to believe it was an issue that they addressed.

 

Totally agree Brian. The biggest cause seems to be on barely used cars where the battery has been left to partially discharge. When it is started the alternator goes crazy and the cable overheats. These cars take a lot of juice to start from cold and if it isn't available then the inevitable happens...

 

Well that would make a bit of sense prior to my ownership. I am a user and caretaker of my car now so it is being used as designed which was not the case for the first owner.

 

Thanks for the great info everyone.

Does anyone have a photo for sharing so I know what to look for?

Dan

 

Which Fcar of yours; the 355 or CS?

 

Here ya go...notice how everything looks wonderfully new except the cable!

Pictures Ref:

1. In car found condition
2. Cable examination
3. Service Manual diagram
4. Ferrari Cable Part (complex = expensive)

Note: I think I was interpreting the cap over the starter motor end as a new configuration of the cable and after further review the alternator end looks the same.
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Thanks for the photos and info Kevin!

I am an electrical engineer by trade so what everyone said was true.

Overheating cables can be caused by: Improper crimp of the cable to the terminal lug thereby there is no solid connection and no stable transfer of power.
Loose connection / nut not fully tightened the lug nut to the alternator, starter, etc.

I will check mine this weekend. Thanks again for the info and photos.

Dan

 

How difficult is it to remove the undertray?

Dan

 

Can the cable not be repaired at the failed end?

 

It's not a difficult job but it's a bit of a PIA and you do need the right tools (jacks, stands etc)

It's not a a bad idea to have a helper to assist with the removal and re-install but it can be done solo with a little extra PIA.

I'm sure there must be details in one or more of the DIY threads and it's definitely in the WSM.

 

Thanks for the info.

I will do a search soon.

Dan

 

If you have one of those electric Dewalt drivers with a 10mm socket it can be off in 10 minutes! this redneck backs the car onto ramps (black plastic ones) and then reaches under with the driver and they just power right out. Unscrew at the rear and it drops down.

If the electrical system assumes zero or near zero resistance in the line from the alternator to the starter.. why no just clean off the terminal and run another thick line to the starter terminal. In essence another pipe for the electricity. If mine goes I'm doing this.

 

Is this limited to the 360 or does the 430 have the same issue?

 

It would seem an easy fix without having to spend mega$$ on an OEM cable. Cut off bad section and splice a new end on with soldered connections -- not crimped. Heat shrink.
Alan

 

The CS

 

I was out of town for a couple of days and just catching up on this.

The photos are exactly what my cable looked like but my car is probably a higher mileage CS with about 22K miles on it and I keep it on a battery tender when it's not being driven so the battery never really discharges.

There was very clear corrosion so I suspect this is a design issue and not a maintenance/use issue. I didn't realize this is a known problem but the responses to the post have been spot on regarding the design issues. When we put the section of cable in (did the splice) we probably went overboard on the prep and heat shrink but we didn't want a recurrence.

 

Thanks for the info Curt,

Yes, I own two power drill / drivers that I always use when removing lots of screws and bolts and always makes life easier.

You and Allan are also correct. No need to spend big bucks to fix this issue.

If there is enough slack on the cable we can cut off the original terminal lug and crimp or even better solder a new terminal lug for the most solid connection.

If there is not enough cable slack to put a new terminal lug in you can run a new cable in parallel to the original one.

I agree with the other post too. Corrosion is not good. Its usually sign of incompatible metals bonded together. I would remove the connection, clean it really well for a solid connection and even look into replacing the terminal lug with same metal its hooked up to.

Dan