Alternator Screwed?

[Alan_M 66 1 Cars]

Some time ago I posted about an issue I had with a brand new (refurbed) alternator not charging at high revs. Not really thought much about it as I need the car everyday at the moment.

 

But on Saturday I decided to have poke about as on the previous evening, the car started to struggle with lights and the battery light popping up a couple of times. Checked the charge volts and that was a healthy 14.4v at 2krpm, and was maintained with full beam beams, rad fan etc on. The excitor crimp was a little loose on the terminal, so I recrimped it. Fired the car back up and the no-charge light was up....Really scratching my head now. Turned car back off to check connections, refired and it was gone! I bloody hate these faults! Figured I'd leave it now as it was working, and later on in the evening went out in the car. Got to Bracknell (10miles away) and the no-charge light was flashing on/off, and then came permanently on. Pulled over to have a poke about, wiggled a wire which made it go away and come back. Figured I better get home on what I've got left.

 

Had a look yesterday, the excitor wire was 12v so no worries there (grounded it too, light came on). The ring terminal was a little tired so I re-terminated that and the no-charge light had gone. Checked the voltage and it's 14.4v etc, dropping to 13.6v with full beams, rear window demist, heater fan (which is f***ed) and 2nd rad fan (set at high speed). Took it for a spin and it's OK, but it still has the high rev issue.

 

I've got the previous alternator still (80A Valeo item) and there is a place near my work that refurbs starters/alternators/dynamos. He'll bench test them first to tell exactly whats wrong too. Might get it refurbed, fit it with all new wiring including an excitor wire straight to the dash bypassing the link-loom connection. Only way to be sure!

[smithy 1]

I would check other end of exciter wire in the brown plug on top of bell housing.

Known weak point for corrosion and high ohms.

[Alan_M 66 1 Cars]

I would check other end of exciter wire in the brown plug on top of bell housing.

Known weak point for corrosion and high ohms.

 

It's an Mi16 so doesn't have the brown multiplug. But I did check the resistance of the excitor wire and main battery cable, both are negligible (0.01ohms).

[Anthony 1,003]

When the battery light is on / flickering, is the alternator giving out any charge? A multimeter connected to the back of the ciggie lighter socket is useful for this

 

Certainly the fact that it's intermittently struggling even with the revs up (when it would self-excite if there were anything amiss with the exciter wire) points at the alternator to me, and mirrors symptoms I've seen on alternators when they're dying. Clearly a properly reconditioned alternator shouldn't do that in just 6 months, but I for one am very dubious of many "reconditioned" parts. Indeed, I do wonder sometimes how much is actually "reconditioned" as opposed to just checking that it works, new brushes and making the outside look as-new...

 

If you've still got some 8v alternators kicking around in your garage, they'll work fine - just need to run a slimmer belt as the pulley is one groove thinner. You could probably swap the pulleys over if you've access to an impact gun at work, but I've never tried it. Alternatively, there's always the red shed to canabalise...

 

I would check other end of exciter wire in the brown plug on top of bell housing.

Known weak point for corrosion and high ohms.

That would cause the opposite issue though, and for the battery light to not light up at all. If the light is on, it's generally either because the alternator isn't charging, or because the exciter wire is shorting against the block, thus grounding it.

[Alan_M 66 1 Cars]

When the battery light is on / flickering, is the alternator giving out any charge? A multimeter connected to the back of the ciggie lighter socket is useful for this

 

Never thought of that, but the battery is behind the passenger seat anyway. Thats the next plan...check if it really is charging on high revs. If not, back to GSF it is! Alternators got a year warranty. But I'm on nights this week, and can't see the meter display!

 

Certainly the fact that it's intermittently struggling even with the revs up (when it would self-excite if there were anything amiss with the exciter wire) points at the alternator to me, and mirrors symptoms I've seen on alternators when they're dying. Clearly a properly reconditioned alternator shouldn't do that in just 6 months, but I for one am very dubious of many "reconditioned" parts. Indeed, I do wonder sometimes how much is actually "reconditioned" as opposed to just checking that it works, new brushes and making the outside look as-new...

 

If you've still got some 8v alternators kicking around in your garage, they'll work fine - just need to run a slimmer belt as the pulley is one groove thinner. You could probably swap the pulleys over if you've access to an impact gun at work, but I've never tried it. Alternatively, there's always the red shed to canabalise...

 

I'm taking the old unit to a decent, well-regarded started/alternator/dynamo refurber near work. Been going for years apparently, and usually has the parts on the shelf. And out of the 5 spare alternators I have in the garage, none work! One off the red shed went to Rob!

[Anthony 1,003]

I'm taking the old unit to a decent, well-regarded started/alternator/dynamo refurber near work. Been going for years apparently, and usually has the parts on the shelf. And out of the 5 spare alternators I have in the garage, none work! One off the red shed went to Rob!

If you get stuck I've got a few alternators in my garage that worked fine when they were removed.

 

Be interested to see how you get on at that place, as I've got a shiny zero-mile "reconditioned" alternator in a box in the garage that, annoyingly, doesn't work, only I didn't discover that until long after the warranty expired as I'd only bought it as a spare No charge whatsoever, battery light constantly lit. Grrrr. I guess I ought to do something with it and get it fixed or condemed, as it's little more than a doorstop as it stands.

[Alan_M 66 1 Cars]

Seems as though I'm not the only one to suffer the wrath of 'refurbed' alternators from GSF!

 

http://forum.205gtidrivers.com/index.php?s...tor++flickering

 

Got a known working alternator (thanks Rob) so hopefully it'll sort it. Not been to bed yet after my nightshift, so replacement may be slow

[Alan_M 66 1 Cars]

Fitted alternator and all seems tip-top. Bright headlights instrument cluster again.

 

Pretty conclusive it was a dodgy alternator.