Ford Mondeo III (2000 - 2007) - 2002 2.0tddi - alternator problem

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Wed 22 Oct 2008 20:52
2002 2.0tddi - alternator problem - marc1972
my battery went dead so i bought a recon alternator i put it on it turned over with a bit of help i tested the battery and it was chargeing ok then it said alternator faulty over chargeing after about 5 mins the car died and a bad smell came from the alternator now it wont charge is there a relay on the car anywhere that u have to change as well as the alternator thanx for your help

Edited by Dynamic Dave on 23/10/2008 at 00:34

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Wed 22 Oct 2008 21:59
02 2.0 alternator problem 2002 diesel tddi mondeo - Screwloose
marc

If you don't recharge the battery; it's common for the new alternator to burn out shortly after fitting - particularly on a car with a smart charging system.
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Thu 23 Oct 2008 19:49
02 2.0 alternator problem 2002 diesel tddi mondeo - TurboD
Bad smell is the burnt out windings- they are coated in a sort of lacquer.
Just like cheap and nasty electrical tools from discount stores
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Thu 23 Oct 2008 20:04
02 2.0 alternator problem 2002 diesel tddi mondeo - 659FBE
Any properly designed automotive alternator is fully self-protected against burn out due to overload. This is achieved by a combination of armature reaction which incresingly neutralises the field flux as the output current increases and the rising reactance of the stator which again limits the current as the frequency (revs) increases. This is why car alternators don't have a current regulator - unlike the old DC systems.

I wonder if the Ford bean counter division has done to alternators what it did to diesel fuel systems?

659.
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Thu 23 Oct 2008 20:32
02 2.0 alternator problem 2002 diesel tddi mondeo - Screwloose
659

I've never seen stator windings fry under those circumstances either.

The cheap and nasty output diodes in a re-con unit are a different matter altogether.
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Thu 23 Oct 2008 22:55
02 2.0 alternator problem 2002 diesel tddi mondeo - marc1972
hi thanx for all your help took altinaor back today got another recon same thing happend took it off took it to ford garage he said is it putting out to much amp it should be putting out 90 amp im takin it back tommoz he said he had a new one for £95 plus vat but someone said to me it could be the battery any ideas i havnt got a clue cheers
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Thu 23 Oct 2008 23:16
02 2.0 alternator problem 2002 diesel tddi mondeo - Screwloose
marc

Maybe some testing and diagnosis would have been worthwhile before fitting parts.

Have you recharged the battery.
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Thu 23 Oct 2008 23:25
02 2.0 alternator problem 2002 diesel tddi mondeo - cheddar
Could the battery be the culprit after all?

Screwloose, are you saying that a new alternator will burn out if the battery is not recharged, what about if the battery is flat due to leaving the lights on etc and the car is started via a jump from a good battery?
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Thu 23 Oct 2008 23:38
02 2.0 alternator problem 2002 diesel tddi mondeo - marc1972
the battery needed to be jumped yesterday but was put on charge all night from what was put on here it fired up streight away today then after a few seconds went to altinator fauty over chargeing sorry if i am driving people mad i feel like driving it off a cliff with me in it thats what my wife said lol HELP and thanx
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Thu 23 Oct 2008 23:43
02 2.0 alternator problem 2002 diesel tddi mondeo - Screwloose
marc

The alternator is a slave unit of the engine ECU. Get the fault-codes read next to see if the demise of the first one damaged the ECU.

While they're at it; get them to check the voltage drop in the alternator's output circuit.
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Thu 23 Oct 2008 23:40
02 2.0 alternator problem 2002 diesel tddi mondeo - Screwloose
cheddar

Nearly all replacement alternators have a warning in their fitting instructions concerning recharging the battery before fitment. It's a question of cushioning the initial running of a new alternator.

An existing unit is well-settled and can withstand the period of high load more easily. New diodes seem very vulnerable to high load until thay have bedded-in through a few heat-cycles.

This known problem is magnified several times by the high initial voltage of this car's smart charging system - the first few minutes are at around 16 volts.

Jump-starting has it's own dangers - as discussed many times - but alternators rarely seem to fail.
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Fri 24 Oct 2008 10:13
02 2.0 alternator problem 2002 diesel tddi mondeo - cheddar
Thanks Screwloose.
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