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sbn1979

Alternator charge issue

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Evo 8 260 everything fine before ecu swap, now battery light, brake warning and low oil level light comes on when revving the car, battery voltage now at 11.6 also, any help appreciated 

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Where are you measuring the voltage at the battery or off the ECU ?

If you are measuring 11.6v at the battery the alternator is either not charging.

If your seeing the voltage on the ECU Software, then you need to measure your battery voltage and if thats ok you have a bad earth or positive connection.

If all the lights are doing it I would guess and earth, but please check above first.

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If the battery light is flashing up on the dash (plus others) its probably not charging at all, and when you rev it the additional drain is dropping the voltage low enough to trigger the light. Do you have a wiring diagram for the car? A lot of cars have a "field" wire to the alternator that needs to be provided with 12v at key on so alternator will provide charge. if this came via the ecu or a relay that you changed wiring on and now isnt hooked up it can cause what you're seeing. 

So could

1) a faulty alternator

2) the ground for the alternator not being hooked up (if it was spliced into or through the ecu wiring which is now different)

3) some alternators have a "kill switch"/low output wire where they can be signalled to turn off (at low load or full throttle usually). depending on the factory behaviour of ground vs 12v vs floating this wire may now be permanently signalling the alternator to switch off.

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