Ok got a M10 316i which will jump start straight away but not on its own, once started runs sweet as a nut.
Do I replace the alternator, the voltage regulator or both for good measure? Already replaced the belt and put a new battery on the car and the alternator connections seem fine.
Any other thoughts?
Alternator
Moderator: martauto
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votivequagmire
- E30 Zone Regular
- Posts: 428
- Joined: Wed May 24, 2006 11:00 pm
- Location: Swansea, South Wales.
Normally the brushes wear out which fails to recharge. Have you a volt meter to do a basic test of voltage to the battery, it really needs a proper test but as a quick test it should be giving 13.5V to the battery when running?
If it doesn't give this voltage then inspect the brushes by removing the VR, but first disconnect the battery.
It's rare for the alternator itself to fail. Replacement of the entire alternator is only called for in the case of bad bearings, a bad diode, or shorted windings.
If it doesn't give this voltage then inspect the brushes by removing the VR, but first disconnect the battery.
It's rare for the alternator itself to fail. Replacement of the entire alternator is only called for in the case of bad bearings, a bad diode, or shorted windings.
'88 325i M20, could've done with a sunroof.
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Brianmoooore
- E30 Zone Team Member
- Posts: 49360
- Joined: Mon Jan 10, 2005 11:00 pm
If one of the brushes seems very short, and shows signs of arcing on the working end, then give it a gentle pull to completely straighten the copper braid that retains it.
This should restore it to full working order for several months, and confirm the diagnosis.
This should restore it to full working order for several months, and confirm the diagnosis.
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m8782538
- E30 Zone Squatter
- Posts: 1550
- Joined: Mon Feb 07, 2011 11:00 pm
- Location: Swindon
Sorry for the delay, no voltmeter, once jumped it runs well but once turned off there is nothing, not even the service indicator lights. The battery was good as it was brand new but now is just not charging.
I will check the bushes and replace the voltage regulator as its a cheap part. This car has been layed up and off the road for around 7 years. Corrosion is bad, still trying to get cheap quotes for the welding too (repair 1 sill, replace the other, front arch and a couple of other patches (£600 best quote so far) if i provide the replacement sill.
I will check the bushes and replace the voltage regulator as its a cheap part. This car has been layed up and off the road for around 7 years. Corrosion is bad, still trying to get cheap quotes for the welding too (repair 1 sill, replace the other, front arch and a couple of other patches (£600 best quote so far) if i provide the replacement sill.