B230FD Problems :)

[Volvo940GL]

Originally Posted by Laird Scooby

It can probably be fixed but you need to check the earth strap from alternator to engine first. That would cause the symptom you're getting, as would a duff rectifier inside the alternator.

That's without any other faults that may come to light when it's stripped down so there may be other faults causing the symptoms, not limited to but including a worn or incorrect drive belt, incorrect tension on the belt and several others.

I'm a few thousand miles away and can not see exactly what it's doing, however the fact the charge warning light and the others that are linked to it when the alternator isn't charging are on, even dimly points to an alternator fault so it's not charging. Could explain the flat battery!

Also if the engine management ECU doesn't see the correct charging voltage, it will throw everything out of kilter and cause among other things, rough running, misfires and umpteen other possible problems!

Battery shows 12.71V while engine is off
Alternator shows 14,05
And battery shows 14.05
When engine almost stalls it shows 13.85v

Did another test
Battery 12,7volt
Alternator between 13.85-14.05v
Battery shows 13-85-14.20v
3000rpm It shows 14,5 volt
I cleaned ground and that big and small red cable behind the alternator. I did ofc remove minus pole from the battery

Alternator is 62a right?

Can I upgrade to 100a?


That regulator is new aswell