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RB25 Charging issues

OO Dan OO

By OO Dan OO,
in Car Audio & Electrical

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OO Dan OO Enthusiast

OO Dan OO

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I took my Skyza out to a wet pan event and whilst waiting my turn my car just died. I Jumped it and my voltage was just over 12. Keeping the revs up I was able to keep the car running. But voltage was still quite low. Then all of a sudden 13.8 for a bit then back down. It kept going up and down my whole trip home.

does this sound like a dodgy Alternator?

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OO Dan OO Enthusiast

OO Dan OO

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On 27/6/2023 at 8:56 AM, GTSBoy said:

And let's not bother finding out what is actually wrong.

Hey mate, I think the problem is actually the alternator light. I don't Chet the charge light coming on at all. Here is where it is currently plugged in to. Perils of picking up someone else's project. In the pic the circled bit is where the light wire is going. It is a white/red wire on the other side

 

IMG_4698.jpeg

IMG_4697.jpeg

OO Dan OO Enthusiast

OO Dan OO

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On 30/6/2023 at 5:54 PM, GTSBoy said:

Yuh, so break out the multimeter and check the wiring. Pull the dash out and check the globe locally.

Ok, I have pulled the cluster out. The bulb is fine. There is power at both sides of the globe.

does this mean the Alternator is not earthing the wire when the ignition is on but car not running?

does this tell you anything?

GTSBoy Grand Master

GTSBoy

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5 hours ago, OO Dan OO said:

There is power at both sides of the globe.

If you have power both sides, then yes, there is no earth. That wire runs through the alternator as the exciter, which causes it to start producing current, which it will not reliably do without the excitation. You can follow it on the wiring diagram to see where it goes.

OO Dan OO Enthusiast

OO Dan OO

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1 hour ago, GTSBoy said:

If you have power both sides, then yes, there is no earth. That wire runs through the alternator as the exciter, which causes it to start producing current, which it will not reliably do without the excitation. You can follow it on the wiring diagram to see where it goes.

I noticed there is no earth wire bolted to the back of the alternator. I clipped my test light on this bolt and tested a live wire to see if it is grounded and I got sparks. Does this mean my alternator is possibly just not grounding enough?

GTSBoy Grand Master

GTSBoy

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1 hour ago, OO Dan OO said:

I noticed there is no earth wire bolted to the back of the alternator. I clipped my test light on this bolt and tested a live wire to see if it is grounded and I got sparks. Does this mean my alternator is possibly just not grounding enough?

Impossible to say.

Get the wiring diagram. Make sure you have the same wiring as the diagram. If you have the same wiring, and it has continuity where it should, AND shit's not working.....then you suspect the alternator has a fault.

Duncan Grand Master

Duncan

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Just don't mistake the main power stud with a grounding point, there are a few different model alternators on these, but AFAIK they all have an M6 stud for the positive and an m5 bolt or stud for the earth. 

It does need to be earthed to charge properly

OO Dan OO Enthusiast

OO Dan OO

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45 minutes ago, Duncan said:

Just don't mistake the main power stud with a grounding point, there are a few different model alternators on these, but AFAIK they all have an M6 stud for the positive and an m5 bolt or stud for the earth. 

It does need to be earthed to charge properly

It is a little bolt that I am talking about. Definitely not a stud. It doesn't have power just not earthed

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