Second Alternator failure !

M

mabo

Club Member
Nov 13, 2011
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south wales
So, I had the flickering light problem and did the alty fix linking one of the wires to the alty output.
Then a few months later on a trip to Italy the Cougar died, flat battery. Jump started by French RAC equivilant, loaded onto a beaver tail and deposited at the nearest ford main dealer. They said alty knackered, I said carry on, change it. We picked up a fiesta hire car and continued to Italy. 7 or so days later we hear the Cougar is fixed. We return to the dealer, drop off the Fiesta, pay the bill and drive away with a new Ford Alty and Ford battery. It cost me for the install etc but I probably saved half of that amount in fuel, and I didn't have the dreaded job of changing thing.
Back home I noticed the lights flickering, turns out they hadn't connected the extra wire, so I did. Job done.
18 Months later she's done exactly the same thing again, flat battery, not charging. I've dropped the alty off and it's a brand new Ford labelled one ( she has only done a couple of thousand on it ) I've doubled checked my "alty fix" wiring and it's as it is supposed to be. Over the next few days I'll take the almost new ford alty to a reputable electrical specialist to see what they have to say. Incidentally all of the fuses in the box under the bonnet are good and it is a silver nitride battery or whatever super dooper type it is supposed to be.
So why the heck is my lil Cougar eating Aternators ?
Over to you.......:(
 
Hi Quicksilver, I can't say I did and thanks for the reminder. The cut end was well insulated and tied back into the loom at the back of the rear cylinder head so I'm sure that ain't shorting anywhere. Will pull it out tomorrow, hard to see how that would cause the alty to fail tho. I'm not familiar with the circuit but a stray live insulated end taking out the alty ?
 
I'm not suggesting it would cause the alty to fail. The advice to remove the fuse was included in the info from the Ford TSB associated with the alty fix where the method detailed was to splice an extra tail for the main alty connector into the red wire rather than cutting the red wire. Splicing into the red wire would leave the circuit complete unless the fuse was removed. As you have cut the wire, whether the fuse is in or out, is probably immaterial.
 
Failure mode? If we're talking about code here then I haven't a clue.
First sign of a problem on both occasions has been the ABS warning light coming on then various other warning lights illuminating. Just managed to limp the car home this second time. After giving the battery a boost for an hour she started happily enough but a multimeter set on volts across the battery with the engine running showed less than 12v, I believe 14v or more is normal. Hence my diagnosis of a knackered alty. Incidentally this is exactly what the french Ford dealer did in front of me to diagnose the knackered Alty.

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Quicksilver said:
I'm not suggesting it would cause the alty to fail. The advice to remove the fuse was included in the info from the Ford TSB associated with the alty fix where the method detailed was to splice an extra tail for the main alty connector into the red wire rather than cutting the red wire. Splicing into the red wire would leave the circuit complete unless the fuse was removed. As you have cut the wire, whether the fuse is in or out, is probably immaterial.
Click to expand...
Thanks again Quicksilver, Seems you confirm the result would be the same either way, and not cause alty failure.
 
What I mean is, has the alternator cooked the battery, have the windings shorted, has the regulator failed, is the internal resistance of the battery huge and over-loaded the alternator?

All are different cause/effect.
 
benham said:
What I mean is, has the alternator cooked the battery, have the windings shorted, has the regulator failed, is the internal resistance of the battery huge and over-loaded the alternator?

All are different cause/effect.
Click to expand...

Hi Benham and thanks for your interest. I'll drop the Alty to a local reputable auto elec co. next week so I'll know more then.
But the present guess work is...
Has the alty cooked the battery, ? Dunno, hopefully not but seems possible.
Have the windings shorted, ? Dunno, but it seems unlikely but I'll know more after the experts check it out.
Has the regulator failed ? My guess is yes but as above to be confirmed.
Is the internal resistance of the battery huge and overloaded the alternator. Dunno, seems unlikely. The present battery was installed when the alty was changed in France in 2013. As the breakdown incident was identical on both occasions and both alty and battery where changed after that first failure I'm looking for a common factor, ie something on the car that isn't alty or battery that is causing the failure, hence my original suspicion that maybe I'd got the alty flickering light fix wrong.
As a solution, admittedly an unlikely one, I'm even wondering if it's possible to mount the regulator away from the alty and therefore more access able but need to prove that is the failed part. But that is treating the problem, really I want to fix the cause.
 
My next step would be to assess the battery, might give you a clue.

Bench charge it if you can then get it to any reasonable motor factor for a condition test.

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My next step would be to assess the battery, might give you a clue.

Bench charge it if you can then get it to any reasonable motor factor for a condition test.
 
So the latest news..
Dropped the Alty to a reputable Auto Elec Co today. They soon called me to say initially it was functioning but suddenly the output failed this makes it sound like a Diode failure. Further diagnosis was a knackered regulator and gave me a cost to replace it. Initially I said carry on but then had a rethink. We agreed they would get the rectifier in and we'd have a look at both tomorrow to see if there is any way it can be remote mounted from the Alty to facilitate easier replacement next time it fails. No hints yet as to the cause other than these things are made for peanuts in the far east and quality isn't anything special. If I'd bought a cheap unit from Ebay I would be less surprised but the alty looks like a genuine Ford component, I seem to recall it was also marked made in Korea. I'm off now to google pics of the alty and regulator to see if there is any mileage in my crazy remote mount idea !

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benham said:
What I mean is, has the alternator cooked the battery, have the windings shorted, has the regulator failed, is the internal resistance of the battery huge and over-loaded the alternator?

All are different cause/effect.
Click to expand...

Hi Benham, thinking about your list above you mention high battery resistance as possible cause of failure. The cougar had recently been into my local garage for an MOT, they did some bits to help it to pass. Afterwards I found that the neg terminal on the battery was loose. I don't know why they would have had the terminal off, maybe they didn't. BUT a loose battery connection would be similar to the high battery resistance you mention. Is this a likely cause of the failure of the rectifier ?
 
yep a bad battery connection will defo bugger up ur regulator after a while..im sure benham would agree ya:geek:

you can get separate regulators but the only trouble u will have is the brushes and regulator are all one unit and youd need to bypass the old one somehow...but then u can change the regulator without removing the alty from the car ,u do still have to get under it though and its tight space near the manifold.
 
Oh I agree, if you've got any high resistance connections in the system they'll add undue load on to the alternator, especially the battery terminals which I guess in a way are the cardinal connections. You could (I imagine) have quite a volt-drop with poor battery terminal connections, I'm going to have a play in my car in a bit to see how bad I could make the situation.

Rotating electrics aren't my area of knowledge (indeed, it's all pretty sketchy!) but I can't see why an external regulator would be an issue, in fact many older cars have regulators separate to the dynamo, but here's the rub.....

Dynamos had the useful feature of working like a little DC motor you'd find in a Mechano set and are about as simple as they come, it's just(1) a basic DC motor that's spun by the engine, output is in DC and the regulator just keeps things running sweetly at 12v, the regulators were quite a basic bit of discreet electronics(2) - keep everything running just nicely to top the battery up..... They couldn't produce a lot of power at low RPM, that's why vintage cars often have headlamps that dim and flicker at idle and 6v systems were not uncommon.

Alternators are much smarter, they're three-phase generators - great as even at low-RPM there are three phases working to keep the lamps sparkly, but the output directly from the alternator is 12v(3) 3-phase AC which means that to move the rectifier somewhere else would require some meaty cabling to move all three phases (as it's going to DC it's balanced so we don't require a neutral conductor) to "somewhere else" - it's certainly doable beyond a shadow of a doubt, but it's going to be a minimum of three fairly substantial cables you'll need to run to the location of the external rectifier -> regulator. You'll also be trunking a fairly substantial AC cable-set across the engine bay which I think could mean you potentially might have to think about the implications of interference too.

If the rectifier has failed they can be simply repaired with bits from Maplins for the cost of a few pounds, but why did it fail, that's probably the more important question.

I hope that this isn't coming across as a smart-arse answer (indeed somebody beyond my wit will probably tear it apart!) but yes it's doable, but it's a fair bit of work!

1) I can hear the itching teeth
2) More often than not, electro-mechanical
3) For the purposes of this conversation, three-phase equations get complex quite quickly.
4) 12v is nominal.
 
Hi Benham. We seem to have agreed on the most likely cause of the failure, the loose battery connection, I'll have to keep an eye on that one.
I had a chat with the guy in the workshop and in all honesty it wouldn't be too difficult to remote mount the rectifier unit. The rectifier and brush unit seem to be two components and the joining method is also the elec connection between the two and only two cables. So the brush could be on the alty, a plate made up to carry the connections ( maybe made from the duff regulator ? ) then cables from the two fixing point up to where ever the rectifier was mounted. The 3 pin would need to be extended too but again hardly rocket science. The new loom could be routed up the inner wing maybe away from the heat of the rear down pipe. I reckon that's half the problem. Ford decided it would be a good idea to mount the electronic components on the back of the alty nice and close to the down pipe cat that is designed to run nice n hot.
So I've decided for now to put everything back as ford design but if the reg fails again anytime soon then I'll def modify it next time the alty is out. Thanks for your help to all that have replied and hopefully my experiences will add to the general knowledge of the forum. Cheers Mabo.
 
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