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 Alternator slowing engine? 
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Firing on two.
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Joined: August 19th, 2010, 10:44 pm
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Post Alternator slowing engine?
Help.I have just got Trevor on the road and have noticed a strange noise coming from the alternator.Its a new Valeo,also a new battery.If I dissconnect the grey wire from the ex. terminal on the alternator,the noise goes and the revs pick up quite a bit.Checked the voltage on a meter,and it seems to be putting out 15 volts on idle :o .I have got 12v on the grey wire with the ign. on,but when the engine is running,it fluctuates,and is in rhythm with the noise I can hear.(a sort of rubbing noise).The alternator seems to be working overtime at idle,slowing the engine.
Any ideas?

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June 5th, 2011, 4:24 pm
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Joined: April 24th, 2010, 10:01 am
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Post Re: Alternator slowing engine?
chuck the battery on charge over night, maybe the battery isnt up to full capacity

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June 5th, 2011, 5:27 pm
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Agony Aunt - You have a car problem? Speak to Ken

Joined: March 6th, 2009, 1:40 am
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Post Re: Alternator slowing engine?
Dave,
your regulator isn't regulating, either because it's faulty or the wiring to it isn't as it should be.

First, you need to check if the earth pin on the 3 way plug has a good connection to earth.
That would be my first guess in this case.

But, if that is OK, check for resistance in the 12 volt feed to the regulator, as that can also trick the regulator into demanding too high a voltage from the alternator.

When things are working as they should, the excitation voltage at the smaller connection on the alternator should drop below 6 volts as the engine speed is increased...

ken.



dave 411 wrote:
Help.I have just got Trevor on the road and have noticed a strange noise coming from the alternator.Its a new Valeo,also a new battery.If I dissconnect the grey wire from the ex. terminal on the alternator,the noise goes and the revs pick up quite a bit.Checked the voltage on a meter,and it seems to be putting out 15 volts on idle :o .I have got 12v on the grey wire with the ign. on,but when the engine is running,it fluctuates,and is in rhythm with the noise I can hear.(a sort of rubbing noise).The alternator seems to be working overtime at idle,slowing the engine.
Any ideas?

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June 5th, 2011, 5:55 pm
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Firing on two.
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Joined: July 9th, 2009, 10:27 am
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Post Re: Alternator slowing engine?
The fastest my car ever went was when the wire dropped off the back of the alternator. Was happily sitting in the outside lane of the M40 with the needle well off the end of the scale.
Of course it wouldn't start again in the morning though!


June 6th, 2011, 1:33 pm
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Firing on two.

Joined: April 22nd, 2009, 11:06 pm
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Post Re: Alternator slowing engine?
thats why racers have a Kill switch for the alternator ( legal or not!)

its a big magnetic brake when its charging the battery-running all the electrical guff etc

shouldn't put out more than 14.5v

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June 6th, 2011, 5:25 pm
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Firing on two.

Joined: February 8th, 2009, 11:39 pm
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Post Re: Alternator slowing engine?
Sorry....a totally stupid and "non-technical" reply (of course...)..

....but did you say your car was called "Trevor" ?......now I am not into naming cars....but what an interesting choice.....maybe I might just name my Bamboo "Bernard" or "Brian" or ....

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June 6th, 2011, 5:42 pm
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Firing on two.
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Post Re: Alternator slowing engine?
Yep,Trevor the 2cv.The wife named him.Also have Rosie the red spesh.She named her too.Keeps her happy,and she dose'nt moan when the credit card bill comes in full of Ecas purchases :lol:

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June 6th, 2011, 8:06 pm
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