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Thread: Alternator issue...

  1. #1
    aaront's Avatar
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    Alternator issue...

    Hi everyone....first post and I thought I would start of with a question.

    I recently joined the world of Astra owners picking myself up a little holden astra SRI turbo (2.0l turbo) here in Australia.

    Within about a week of owning it the alternator completley died. So I took it to an autoelectrician who replaced the alternator with a new bosch version.

    Took the car home that afternoon but then I started having issues with the engine dropping revs and the battery light fading on slightly took it back to the autoelec and they tested it and apparently the new alternator had a faulty regulator so they changed that over....seemed to fix that problem but I did notice the engine was idling a little rough (dropping a little but just idling a little lumpy) but the electrical issues seemed to be at bay. I took it to the dealer who found that the rocker cover was leaking some oil and fouled the plugs so changed that over and all seemed good but over the last week I have noticed that when I drive at night the initially when you start the car the dash lights and headlights dim and the battery light flashes up briefly. The battery light flashes again a few seconds later and the headlights and dash lights return to normal...

    After driving for a while it stays normal and the problem goes away. But when its sitting at idle it intermitantly occurs.

    I put a multi meter over the battery and when the battery is off it reads about 12.8 volts so the battery seems fine. When I turn the car over it goes up to about 14.5-14.8 fluctuates by a 0.1 of a volt but holds around that so alternator seems to be charging. Turn the lights on and it drops to about 13.9-14.0 volts but seems to hold charge as this problem is intermittent it doesnt always occur but one way I found that seems to force it is by turning on the A\C and lights and the multi meter will drop to about 13.6-13.7 volts but then it seems to force the issue to occur more regularly and what I notice is that the engine will shudder a bit drop revs and the voltage drops right down to about 12v whilst still running at the same time the dash and headlights dim and the battery light flashes on so I am guessing that this is a alternator issue but not sure exactly what as the alternator and voltage regulator are new as is the battery. It seems to be ok to drive as for the most part the alternator is running but on the odd occasion it stops charging so im a bit worried. I will take it down to the auto elect again to look at when they open in a few days but does anyone have any ideas that I can look at in the interim to see if I can save myself a trip.

    Cheers for the help

  2. #2
    GB's Avatar
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    the alternator is over charging

    just as bad as under charging

    14.5-14.8 is too high

    14.4 is usually the max

    then again i MAY be wrong!

    keep it like this however, and the battery will be fried.....

    I hope this doesnt affect your love for the car though

  3. #3
    Autosparks's Avatar
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    14.8v is a high reading for a battery thats being charged by the alternator but then again 12.8v seems high for a battery standing idle so you may find your meters over reading

    Try doing the tests with another multimeter, i'd like to see a max charging of about 14.2v
    Want a professional job done on fitting your aftermarket electrical accessories? PM me for a quote
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