Altinator ISSUE, wrong car, but in general any car

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citroenxm
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Altinator ISSUE, wrong car, but in general any car

Post by citroenxm »

Not much happens on the Renault side, so Ill try here as I need to know ASAP before anything else happens... however, it covers majority of cars...

Problem: Flat battery...

Battery state indicator showing green, an apparently ok battery.

Another known good battery fitted, car back to life, engine running a nice 14.2v into the battery, however, with ALL electrics on thats Lights and full beam, heater blower on full, rear heated screen on, rear fogs on.. engine idleing the Volts are now ALL over the plave, from 0 to 15v, 10v 12v 11v 15v 8v 0v etc etc....

Looks like altinator to me?? Correct??

Paul
Sharing a pug 207 1.6 hdi Sw 16v.
M reg Xm 2.1 td auto exclusive S2 269k and rising
L reg XM V6 12v SEi auto .. Light project

A very sad...
1994 XM 2.1 d auto
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Clogzz
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Post by Clogzz »

Probably nothing wrong, I had that once when measuring with an el cheapo digital multimeter.
At idle with everything switched on, most of the current from the alternator goes into the load and the battery can’t smooth the pulsating alternator voltage.
Say that it’s a metering fault, not a measuring fault and an analogue or upmarket digital meter wouldn’t show that.
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Post by wotwot »

Sorry to state the obvious but have you checked the feed cable from the alternator, as in the connectors both ends.
If these are ok then the diodes are on there way out in the alternator.
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AndersDK
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Post by AndersDK »

Another wellknown issue is a bad earth on the alternator.

Sounds duff, but the problem is light alloy parts mixed with steel mounting bolts & nuts, which inherently calls for white-corrosion on the alloy parts.
The result is a high ohmic earth path.

The solution is to run a separate earth cable from any generator housing bolt to the battey minus pole - or a tested/serviced good earth point on the gearbox earth cable bolt.
This separate earth cable must of course be the same gauge as the charge cable from the alternator.
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citroenxm
Posts: 8061
Joined: 30 Dec 2004, 23:10
Location: Somewhere in North Wales, Anglesey
My Cars: M reg Xm S2 2.1td Auto Exclusive. 269k and rising
L reg XM S1 V6 12v Manual SEi
L 94 XM 2.1 TD auto total resto

2008 Peugeot 207 Sw 1.6 16v hdi. 217k and rising
2010 Peugeot 207 SW 1.6 8v HDi 161k and rising
x 70

Post by citroenxm »

Thanks guys...

I was gussing diodes too... I didn;t beleve for ONE moment a varying voltage was normal! Thats Not a job of an altinator!

Paul
Sharing a pug 207 1.6 hdi Sw 16v.
M reg Xm 2.1 td auto exclusive S2 269k and rising
L reg XM V6 12v SEi auto .. Light project

A very sad...
1994 XM 2.1 d auto
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Post by Peter.N. »

You can get replacement regulator/brush units for most alternators from ebay for not a lot of money, about £12.00 for some. So unless the bearings have gone, well worth considering I would think.

Peter
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