Duff Alternator? Hot wire/ smoke / melty bits

[Jemmo]

Hi all

Drove home from work a few nights ago and noticed that when I started the car, there was a sound that I hadn't noticed in the morning - it was a dull whiney sound.

Got home no problems, no warning light on the dash, but getting out of the car I popped the bonnet to check and there was bit of a burning rubber smell.

Went to start the car next morning and it was completely dead. Couldn't operate the central locking, and not even the time was showing on the LCD dash display.

Charged the Battery up all dat - the initial charge was reading at 7 Amps! Whenever I've charged a Battery before it starts off at perhaps 2.5 to 3 Amps.

So, put the charged up Battery on last night and started the car, went for a drive. Still had the dull whine to start with but it seemed to disappear after a short while.

Popped the bonnet when I came home and there was the slight smell of burning again.

Got a new battery today - checked the pd across the terminals prior to fitting - 12.7V. No problem.

Fitted it and started the car, no problem

Then after a short while there was the slight burning smell again.

I was just about to close the bonnet when I noticed a whiff of smoke.

It was coming from the sleeved wire that connects from the alternator around to the battery pos terminal.

It was coming from both ends.

The wire was very hot to touch and slight movement cased the wire to lose some of the plastic sheath.

Needless to say I have disconnested the battery.

I know little to nothing about car electrics but I am guessing this is symptomatic of a failed alternator?

Is the wire that is melting there to put some life back into the battery?

[Anthony Poli]

Hi, 

It could be the alternator the has bearing problems, the smoke and hot wire would suggest its drawing a large current from the Battery. The fact that you have put a new Battery in and it's the same, is a sign that alternator is your problem. Draining the Battery in the process.

 Best to get someone with car electrics to check that for you.

[+robster+]

if its the b+ terminal that goes to Battery pos this is alternator output to charge Battery and should read around 13.4 to 14.8v when engine is running

 

id be looking for a poor connection on this wire on an 18 year old motor as that can cause heat via excess current through a narrower conductive path.

 

cant say for sure though from this side of the screen. the dull whine sounds like alternator bearings or lock up and belt smokes?

[Jemmo]

Thanks guys - I had a pulley bearing replaced last November and new belts fitted.

When ai put a meter on the Battery with the engine running you could the voltage slowly rise - I didn't mesure from the wire to earth to see what was coming through.

I need to replace the sleeved wire back to the Battery as this is now showing bare wire. I'm not sure what terminal the wire connected to on the alternator as it looks like it ts connected behind a bigger one - same connection.

Have attached some pics of the offending wire connecting to the alternator, and looping around toward the Battery - melty black bits clearly visible.

Just a thought - the yellow connector at the alternator in the last pic - doesn't seem in keeping with being an original part. Does this look like a previous bodge or is this correctly wired and it's probeably just a replacement connector?

[+robster+]

in interest of safety and not going up in smoke. if you have any breakdown cover or even in with your insurance cover. get them out and put the ball in their court to look at it and fix it

 

somethings not right there and id think the fuses should blow before anything got to that stage if original

 

[+robster+]

the yellow eyelet is a bit big for that guage of wire and looks bodge.    it doesn't have a crappy amp or handsfree fitted aftermarket with too high a rated ( or none) fuse fitted !!!! does it.  follow that wire and see where it leads to , it may be a poor bypass for the failed original b+ wire???

[Jemmo]

That wire just goes straight back to the Battery pos terminal. That's the melted wire.

Just seems too coincidental that the whiny sound, flat Battery, and melted wire have all come at once.

Just found this in the web:

Sound: Drivers will sometimes complain about hearing a "growling" or "whining" noise before an alternator gives out. The alternator is driven by either an accessory belt or a serpentine belt in conjunction with the crankshaft pulley. The alternator pulley typically spins about two or three times faster than the crankshaft pulley to produce the power necessary at lower engine speeds, such as at idle. The alternator pulley spins on a shaft, which in turn is supported by either bearings or bushings. If the pulley is not in correct alignment with the belt, if it's canted on the shaft or if the bearings and bushing are worn out, the growling or whining noise will let you know there's a problem.

Smell: The scent of burning rubber or hot wires will often accompany alternator failure. A pulley that isn't in alignment or not turning freely will cause more friction on the belt, which creates heat and then the smell of burning rubber. The hot wire scent can be caused by an overheated alternator, one pushing too much power through the rotor and stator.

[+robster+]

if you can remove alternator you should be able to get it checked free and service exchanged at a auto electrician shop. the wiring still needs adressed

also turn belt inside out to check for cracks and brittle rubber by excess heat and replace if needed

[Konrad C]

I agree with Robbie about going to an auto electrician and having the alternator checked. 

As I sold my Mk1, I can't do the checks to confirm what should be happening.

I am surprised the fusible link did not melt!

 

[Jemmo]

Got the Green Flag chaps out today - diagnosed as a dodgy alternator - shorting out inside. Car now at the local garage - hopefully with their contacts they can quickly source a recon part.

 

Thanks for all the replies chaps.

[Jemmo]

UPDATE - got the car back with new alternator installed, BUT, apparentlty the alternator relay had melted so has been removed.

The melted wire has been removed and a new new fusible link has been fitted direct from the Battery pos to the alternator.

Now, I have no electrics - no indicators, brakes, radio, air-con, windows, rear lights, sun roof etc. The only things that work are the horn, the headlights, and the instrument panel.

One thing I did try was, switch ignition on, turn on wipers/indicators, and I just touched the original main connector to the new connection on the alternator. A few sparks but BINGO!

Not being an electrician, I am guessing that something major has been bypassed by the new fusible link.

Reckon I'm going to have to give them another shout tomorow

[Xmas]

If you detect a burning smell you should unmake the Battery earth connection immediate and then called your local auto service person.

You can attend a course on auto maintenance, there may be one on the web.

The risk is having to make a claim for fire on your auto insurance.

It is rare that an alternator fails with a short circuit but it creates a fire hazard when it does.