Alternator problems again

Andyiow · Mar 9th, 2017, 14:28

Seems I am not having much luck with alternators in my 440.

Battery not charging again despite it being only 2 years old and less than 18 months since it was fitted.

Had the car running and checked the battery voltage which was 12.8v and then taken up to 2000rpm it was just a fraction more than that.
There is not light on the dashboard indicating a problem but the rev counter is not working which comes directly from the alternator.

Wondering if there is a wiring fault as the battery light comes on when you first turn the ignition key and goes out when the engine is running.

Any thoughts?
Going to disconnect the rev counter wire and the charging wire and measure the voltage on each terminal.

Jiff Lemon · Mar 9th, 2017, 14:40

Got a voltmeter?

Check the voltage directly at the alternator + terminal whilst running. Should be 14.5v at least. If it's reading battery voltage, it's dead.

Check it again under some load (headlamps on, Heated Rear Window, heater fan on full). It shouldn't drop below 13.5v

Then finally, measure from Alternator + to battery +.
then from alternator casing to Battery -

You shouldn't see anything more .5v

Anything more than that and you need to either add/clean up your positive / earth connections.

Andyiow · Mar 20th, 2017, 08:13

Right here are the voltages
Battery with car off - 12.7v
Battery with car running -12.6v
Voltage at Alternator - 12.6v
About 0.05v different between chassis and battery earths.

Battery light on dash board on when engine off and off with engine running.

Looks like the regulator circuit not working. So not to search for a replacement regulator. Hoping a relatively easy to replace as getting the whole alternator out is a right pain.

Jiff Lemon · Mar 20th, 2017, 18:47

Yup, would suggest that that there's no output from the alternator.

There's quite a few on Evil bay at the moment.

Andyiow · Mar 22nd, 2017, 20:42

Right sorted it now. Replaced the regulator part £15 from eBay. Now has just over the 14v at idle.

Interesting looking at the bushes, one is worn to a hole so about 5mm. He other bush is worn about 10 mm.

dcw · Mar 22nd, 2017, 22:38

That sounds better! Glad it's sorted.

David

Mar 9th, 2017, 14:28	#1
Andyiow Junior Member Last Online: Mar 27th, 2017 08:10 Join Date: Jan 2009 Location: Ryde	Alternator problems again Seems I am not having much luck with alternators in my 440. Battery not charging again despite it being only 2 years old and less than 18 months since it was fitted. Had the car running and checked the battery voltage which was 12.8v and then taken up to 2000rpm it was just a fraction more than that. There is not light on the dashboard indicating a problem but the rev counter is not working which comes directly from the alternator. Wondering if there is a wiring fault as the battery light comes on when you first turn the ignition key and goes out when the engine is running. Any thoughts? Going to disconnect the rev counter wire and the charging wire and measure the voltage on each terminal.

Mar 22nd, 2017, 22:38	#6
dcw VOC Member Last Online: Mar 29th, 2024 08:23 Join Date: Jan 2007 Location: YORK	That sounds better! Glad it's sorted. David __________________ VOC 400 Series Register Keeper The current fleet: 1997 440 LE, 1996 460 CD, 1994 480 GT and 2007 V50 SE Sport

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Mar 9th, 2017, 14:40	#2
Jiff Lemon Junior Member Last Online: Apr 15th, 2024 12:10 Join Date: Oct 2006 Location: Milton Keynes	Got a voltmeter? Check the voltage directly at the alternator + terminal whilst running. Should be 14.5v at least. If it's reading battery voltage, it's dead. Check it again under some load (headlamps on, Heated Rear Window, heater fan on full). It shouldn't drop below 13.5v Then finally, measure from Alternator + to battery +. then from alternator casing to Battery - You shouldn't see anything more .5v Anything more than that and you need to either add/clean up your positive / earth connections.

Mar 20th, 2017, 08:13	#3
Andyiow Junior Member Last Online: Mar 27th, 2017 08:10 Join Date: Jan 2009 Location: Ryde	Right here are the voltages Battery with car off - 12.7v Battery with car running -12.6v Voltage at Alternator - 12.6v About 0.05v different between chassis and battery earths. Battery light on dash board on when engine off and off with engine running. Looks like the regulator circuit not working. So not to search for a replacement regulator. Hoping a relatively easy to replace as getting the whole alternator out is a right pain.

Mar 20th, 2017, 18:47	#4
Jiff Lemon Junior Member Last Online: Apr 15th, 2024 12:10 Join Date: Oct 2006 Location: Milton Keynes	Yup, would suggest that that there's no output from the alternator. There's quite a few on Evil bay at the moment.

Mar 22nd, 2017, 20:42	#5
Andyiow Junior Member Last Online: Mar 27th, 2017 08:10 Join Date: Jan 2009 Location: Ryde	Right sorted it now. Replaced the regulator part £15 from eBay. Now has just over the 14v at idle. Interesting looking at the bushes, one is worn to a hole so about 5mm. He other bush is worn about 10 mm.

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