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Voltage gauge, behaviour on start-up

 
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Eliza  



Joined: 17 Aug 2015
Posts: 65
Location: Prov. Utrecht, The Netherlands

PostPosted: Tue Aug 11, 2020 6:31 pm    Post subject: Voltage gauge, behaviour on start-up Reply with quote

Morning all,

Before I go chasing my tail looking for a solution to what may not even be a problem, I need a sanity check.

Of late, I noticed the time it takes my voltage gauge to read the 13.8 Iím used to see after start-up get longer.

Staring the car first time in the morning the gauge slowly climbs from showing battery voltage to showing charging voltage, slowly meaning approx. 10 seconds now itís 25 degrees C at 7:00. Thatís without touching the throttle at all Ė idiot light behaving as it should, indicating the exciter wire works as intended.

I noticed this a few weeks ago and somehow felt it unusually slow. No reference to speak of, just my impression that it rises slower now that it does in colder temps. Would make sense in a way, with fast idling not quite so pronounced in summer as in winter.

So Ė 10 seconds for the alternator to get to work in summer, is this to be expected? Do I need to do something?

Beltís neither slipping nor loose, all looks fine there from where Iím standing. Idle speed when warm is 950 rpm, as per specs.

Thanks in advance for helping me put my mind at rest, or else sort the problem in case it IS one

Eliza
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 929
Location: Maysville, Colorado

PostPosted: Wed Aug 12, 2020 10:06 pm    Post subject: Reply with quote

My suspicion is that the voltage regulator is going bad. I've looked for but haven't found a testing method for the voltage regulator. I'm fighting a dual problem of only having only 11v at the gauge pre-start up(but it starts) and then having the voltage creep up to about up to about 12.5 while running while measuring 13.3 at the battery(should be 13.5-14.5v). I'm loosing about 1.5v at the ignition switch which the gauge circuit reads from('77). First to change voltage regulator(easier) then dig into the voltage loss.
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Paul  



Joined: 02 Nov 2002
Posts: 9451
Location: Southeast Wisconsin

PostPosted: Thu Aug 13, 2020 12:14 am    Post subject: Reply with quote

Are you running A/C when this is happening?
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Fifty50Plus  



Joined: 28 Feb 2008
Posts: 1102
Location: Washington DC area

PostPosted: Thu Aug 13, 2020 3:11 am    Post subject: Reply with quote

Weakening battery?
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Eliza  



Joined: 17 Aug 2015
Posts: 65
Location: Prov. Utrecht, The Netherlands

PostPosted: Thu Aug 13, 2020 2:47 pm    Post subject: Reply with quote

Thanks all!

No A/C ( although I WISH I had one now )

Battery is 6 months old, coonections are clean and solid.

Regulator - might be, although not old enough to make it suspect per se.

Again, my initial decision to ask was more because I was not even certain I had/have a problem? I seem to read between the lines that I do? Do your voltage gauges jump to higher values as soon as the engine runs? I can't for the life of me remember how mine behaved before it started behaving like it does now

How would a failing regulator make itself heard/felt? Mind you, after a few seconds charging voltage is spot-on - only not 'at once' on start-up.

Hmmmm... interesting.

Anyone care to describe how theirs behave?

Eliza
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Eliza  



Joined: 17 Aug 2015
Posts: 65
Location: Prov. Utrecht, The Netherlands

PostPosted: Sun Aug 16, 2020 4:24 pm    Post subject: The resolution Reply with quote

Because I hate it so much whenever I read a post describing EXACTLY what I have and never a follow up - here's what I found caused the sluggish gauge.

The alt belt was a bit loose, but also the cam belt cover wasn't sitting as it should ( a coolant hose clamp behind it needed a quarter of a turn to clear ), eating slowly away at the belt, heating it up, making it stretch. Never heard a squeal though.

So now, a new rubber between block and alernator bracket, new belt properly tensioned and cam belt cover properly positioned, all is well again .

I'm glad I'm usually such a hissy about this car - nine times out of ten, it helps nip BIGGER trouble in the bud.

And she thanks me again for running better than ever - I love this car!

Thanks all who replied,

Eliza
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slowcarfast  



Joined: 03 Jan 2020
Posts: 24
Location: Seattle, WA

PostPosted: Thu Aug 20, 2020 2:42 am    Post subject: Reply with quote

Quote:
Because I hate it so much whenever I read a post describing EXACTLY what I have and never a follow up


x2! Thanks for letting us know what the resolution was.
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