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SteveHobart

Help- Alt not charging

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Hey all

 

I am having some issues with my Alternator not charging the battery.

 

For background, I have completely rewired the car as I have relocated the battery to the boot and installed a MS3X to run the new EFI CrossFlow engine I have built.

 

At the moment I have the 12V input wire to the Alternator running off the Relay for the Thermo Fan (I have checked the input voltage and it’s 11.98V to the Alternator).

 

The alternator output goes straight to the Positive Distribution Block under the bonnet via an (oversized and insulated) charge cable.

 

On the output pin of the alternator I have the insulation disk under the (assuming) voltage regulator and then the output cable.

 

Pics below.

 

The only ‘modification’ to the alternator was I took the pulley off it as my youngest dropped it (for me) and I had to straighten up one of the fins.

 

Help, I have no idea where to go with this next (except replace the Alternator).

 

Cheers

 

Steve

 

9393d468b8a615f98c326a7e086c0c6b.jpg

 

 

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Is the charge light connected?

 

If the dash 'charge' warning light wiring isn't connected, the alternator field windings won't get excited,

thus the alternator won't generate any voltage.

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Hi Dave! Thanks for your input. Yes, the charge light is working correctly, on when in ‘Ignition On’ position and goes out when the car starts.

Still no charge on the alternator


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On 3/13/2021 at 4:15 PM, SteveHobart said:

the only ‘modification’ to the alternator was I took the pulley off it as my youngest dropped it (for me) and I had to straighten up one of the fins.

 

 

very possible something broke in it(due to being dropped). if you have a friendly auto electrician nearby you could drop it in to have looked at? 

 

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3 hours ago, SteveHobart said:

Hi Guys. Yup, alternator checked ok. :)


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some alternators (i haven't looked into it at all) need a POSITIVE wire (ign on from somewhere) added to them to excite them.. @SPArKy_Dave may understand or you might be able to google it and see if that checks out. 

i've only ever used stock for stock or paid an auto elect to fix it

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Yes, it need an exciter wire. It’s the spade terminal on the back of the alternator.
On the XF it’s actually the ALT warning light on the dash providing the exciter charge.
That’s all good on this set up


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Stands to reason, it should work then?

If the charge/alt light goes out, when the vehicle starts, then it should be generating a voltage.

 

Have you earthed the engine block?

(earth from bell housing to firewall, and from cyl head to battery)

 

If the engine block isn't earthed relative to battery negative, the alternator obviously won't work.

 

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