Help near Springfield, MO

Alt or regulator.

Time to get it rebuilt before you blow something expensive

________________________________
From: Gmclist on behalf of Brian Krikorian
Sent: Friday, December 1, 2017 12:50:26 PM
To: gmclist
Subject: Re: [GMCnet] Help near Springfield, MO

Okay.... with all this alternator and isolator talk, I have a question:

On my coach, when I drive under 55, the voltage meter is at about 12-14 (I have one of those that plugs in the cigarette lighter, along with the stock
gauge, and another one on a panel of switches).

When I hit 55 + the thing goes up to 17ish. I've been debating with my mechanic/friend who helps me out whether the alternator is bad. The last time
I had him look at it, they thought it was the isolator and replaced it, and thought that would fix it--but it still would hit 16 to 18 on high speeds.
I began debating maybe it's a bad voltage regulator.

So on my most recent trip, I noticed something new. When I turn on the headlights, it drops down to 10-12 and stays about there. Interestingly
though, if I'm driving city streets at night (below 50mph) my battery starts to drain.

So I'm still thinking alternator is bad. I've switched out the battery as well, and it holds a charge on my garage shelf.

Any thoughts?
--
Brian K
1977 Eleganza II, TZE167V100261
Bellevue, WA
Rebuilt 455, New brake system, a lot of Original Equipment ready to fall apart (discovering more as I go along....)

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Thanks Keith. I suspected as much.

> Alt or regulator.
>
> Time to get it rebuilt before you blow something expensive
>
> ________________________________
> From: Gmclist on behalf of Brian Krikorian
> Sent: Friday, December 1, 2017 12:50:26 PM
> To: gmclist
> Subject: Re: [GMCnet] Help near Springfield, MO
>
> Okay.... with all this alternator and isolator talk, I have a question:
>
> On my coach, when I drive under 55, the voltage meter is at about 12-14 (I have one of those that plugs in the cigarette lighter, along with the
> stock
> gauge, and another one on a panel of switches).
>
> When I hit 55 + the thing goes up to 17ish. I've been debating with my mechanic/friend who helps me out whether the alternator is bad. The last
> time
> I had him look at it, they thought it was the isolator and replaced it, and thought that would fix it--but it still would hit 16 to 18 on high
> speeds.
> I began debating maybe it's a bad voltage regulator.
>
> So on my most recent trip, I noticed something new. When I turn on the headlights, it drops down to 10-12 and stays about there. Interestingly
> though, if I'm driving city streets at night (below 50mph) my battery starts to drain.
>
> So I'm still thinking alternator is bad. I've switched out the battery as well, and it holds a charge on my garage shelf.
>
> Any thoughts?
> --
> Brian K
> 1977 Eleganza II, TZE167V100261
> Bellevue, WA
> Rebuilt 455, New brake system, a lot of Original Equipment ready to fall apart (discovering more as I go along....)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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--
Brian K
1977 Eleganza II, TZE167V100261
Bellevue, WA
Rebuilt 455, New brake system, a lot of Original Equipment ready to fall apart (discovering more as I go along....)
 
> > The sensing wire from the alternator that controls the internal voltage regulator goes to the engine battery.
> >
> > If the 11.8 volts he mentions is the engine battery it could mean that the isolator is indeed bad and the low voltage it is providing to that
> > battery is causing the voltage regulator in the alternator to increase to 20 volts in an effort to increase the voltage to the engine battery. So,
> > I still maintain that he has a bad isolator.
> >
> > Before looking for other causes I would recommend changing the isolator.
> >
> > A quick check could be to move the center wire on the isolator to the top terminal and checking to see if the voltage changes to the
> > approximately 14 volt level. If it does then it definitely is a bad isolator.
> >
> > Emery Stora
> > 77 Kingsley
> > Frederick, CO
>
>
> Ok I moved the center wire to the top post (which is the chassis battery) and it is showing 14.5 volts with the
> engine running so it appears the problem is the isolater and luckily Oreilly has a 70 amp isolater and a 150 amp
> in stock
> If i remember from the is the 70 amp adequate?

Update

Replaced the isolator and now I get bout 14.7 (really cheap meter) hard to tell exactly
on the center and bout 14.1 on both the top and bottom post.


--
Tom Lins
Elkton, FL
77 GM Rear Twin
 
Tom

Glad to hear that you have it working.
As your batteries charge up the voltage should drop a bit.

Emery Stora
77 Kingsley
Frederick, CO

>

>>> The sensing wire from the alternator that controls the internal voltage regulator goes to the engine battery.
>>>
>>> If the 11.8 volts he mentions is the engine battery it could mean that the isolator is indeed bad and the low voltage it is providing to that
>>> battery is causing the voltage regulator in the alternator to increase to 20 volts in an effort to increase the voltage to the engine battery. So,
>>> I still maintain that he has a bad isolator.
>>>
>>> Before looking for other causes I would recommend changing the isolator.
>>>
>>> A quick check could be to move the center wire on the isolator to the top terminal and checking to see if the voltage changes to the
>>> approximately 14 volt level. If it does then it definitely is a bad isolator.
>>>
>>> Emery Stora
>>> 77 Kingsley
>>> Frederick, CO
>>
>>
>> Ok I moved the center wire to the top post (which is the chassis battery) and it is showing 14.5 volts with the
>> engine running so it appears the problem is the isolater and luckily Oreilly has a 70 amp isolater and a 150 amp
>> in stock
>> If i remember from the is the 70 amp adequate?
>
>
>
> Update
>
> Replaced the isolator and now I get bout 14.7 (really cheap meter) hard to tell exactly
> on the center and bout 14.1 on both the top and bottom post.
>
>
> --
> Tom Lins
> Elkton, FL
> 77 GM Rear Twin
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Regulator or remote sense wiring.

> Alt or regulator.
>
> Time to get it rebuilt before you blow something expensive
>
> ________________________________
> From: Gmclist on behalf of Brian
> Krikorian
> Sent: Friday, December 1, 2017 12:50:26 PM
> To: gmclist
> Subject: Re: [GMCnet] Help near Springfield, MO
>
> Okay.... with all this alternator and isolator talk, I have a question:
>
> On my coach, when I drive under 55, the voltage meter is at about 12-14 (I
> have one of those that plugs in the cigarette lighter, along with the stock
> gauge, and another one on a panel of switches).
>
> When I hit 55 + the thing goes up to 17ish. I've been debating with my
> mechanic/friend who helps me out whether the alternator is bad. The last
> time
> I had him look at it, they thought it was the isolator and replaced it,
> and thought that would fix it--but it still would hit 16 to 18 on high
> speeds.
> I began debating maybe it's a bad voltage regulator.
>
> So on my most recent trip, I noticed something new. When I turn on the
> headlights, it drops down to 10-12 and stays about there. Interestingly
> though, if I'm driving city streets at night (below 50mph) my battery
> starts to drain.
>
> So I'm still thinking alternator is bad. I've switched out the battery as
> well, and it holds a charge on my garage shelf.
>
> Any thoughts?
> --
> Brian K
> 1977 Eleganza II, TZE167V100261
> Bellevue, WA
> Rebuilt 455, New brake system, a lot of Original Equipment ready to fall
> apart (discovering more as I go along....)
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*
 
Brian,

I had a similar issue on my coach. I finally found the problem
was where the connector spade in the alternator and the connector
for the sensor wire was not making a good connection.

I pulled the connector wire out and in several times to get
a good connection and the problem stopped.

an easy fix it that's the issue.

larry
 
> Brian,
>
> I had a similar issue on my coach. I finally found the problem
> was where the connector spade in the alternator and the connector
> for the sensor wire was not making a good connection.
>
> I pulled the connector wire out and in several times to get
> a good connection and the problem stopped.
>
> an easy fix it that's the issue.
>
> larry

Had a similar situation on my coach going to Dothan a couple of years ago. I incorrectly diagnosed it as an alternator problem and AZ gave me a new
one that did the same thing. I then found that the female spade connector that plugged into the back of the alternator had lost it's tension on the
sense line. I squeezed the connectors slightly with a pair of pliers and fixed the problem.

BTW, I spotted the problem because I had the previously mentioned $2.00 digital Volt Meter plugged in to my cigarette lighter socket.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
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