| Ground Confusion [message #133419] |
Tue, 05 July 2011 15:24  |
pzerkel
Messages: 212
Registered: September 2007
Location: Salisbury, IL
Karma: 0
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I have had the "hot starts need boost switch" problem for osme time and knew I needed to do something about it.
I have reviewed http://www.gmcmotorhome.info/chassis.html#GROUND
but am confused.
This paragraph is throwing me:
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There should be a large battery cable from the engine battery directly to the starter and then to the chassis. The Engine with the Alternator (the source) and Starter(the load), is the MOTHER of all grounds. All grounds including the Batteries should return to this point. Some owners buy Engine Batteries with side and top terminals so there is a convenient place for this cable. This cable will normally fix the infamous "hot Starter " and "only starts with the Boost Switch" problems. There have been reports of the starting current melting the Oil Dipstick and electrical arcing through the bearings in the transmission.
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Right now I have one cable going from the negative terminal of the engine battery to a point on the engine block. when the text says I need a cable from the engine battery to the starter and then to the chassis. I am not sure what I need to add.
Is there already some point on the chassis to connect this to? If not does that mean drilling a hole in the frame, or attaching it to the aluminum body? In either case where should I do that?
I have not really looked at or for the starter, but is there a ground connection lug on it somewhere already? If not how do I get a ground cable attached to the starter?
Some pictures would be great.
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)
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| Re: Ground Confusion [message #133420 is a reply to message #133419] |
Tue, 05 July 2011 15:30  |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Paul,
Look at Gene's album and presentation..
http://www.gmcmhphotos.com/photos/showgallery.php?cat=5493
Dennis
| pzerkel wrote on Tue, 05 July 2011 15:24 |
I have had the "hot starts need boost switch" problem for osme time and knew I needed to do something about it.
I have reviewed http://www.gmcmotorhome.info/chassis.html#GROUND
but am confused.
This paragraph is throwing me:
--------
There should be a large battery cable from the engine battery directly to the starter and then to the chassis. The Engine with the Alternator (the source) and Starter(the load), is the MOTHER of all grounds. All grounds including the Batteries should return to this point. Some owners buy Engine Batteries with side and top terminals so there is a convenient place for this cable. This cable will normally fix the infamous "hot Starter " and "only starts with the Boost Switch" problems. There have been reports of the starting current melting the Oil Dipstick and electrical arcing through the bearings in the transmission.
------------
Right now I have one cable going from the negative terminal of the engine battery to a point on the engine block. when the text says I need a cable from the engine battery to the starter and then to the chassis. I am not sure what I need to add.
Is there already some point on the chassis to connect this to? If not does that mean drilling a hole in the frame, or attaching it to the aluminum body? In either case where should I do that?
I have not really looked at or for the starter, but is there a ground connection lug on it somewhere already? If not how do I get a ground cable attached to the starter?
Some pictures would be great.
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Ground Confusion [message #133425 is a reply to message #133422] |
Tue, 05 July 2011 15:55 |
Don A
Messages: 895
Registered: October 2008
Location: Dallas, TX
Karma: 0
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Gene, the last slide in your "Easy as 123" says you don't need the boost to start. But does this wiring rearrangement prevent use of the house battery with the boost switch. Supposed I leave a light on and drain the start battery.
[quote titleEASY_AS_123.pdf[/url]
[/quote]
Don Adams Dallas, TX
'76 26' Glenbrook, '90 Sidekick
rebuilt by R Archer, powered by J Bounds, Koba
[IMG]http://www.gmcmhphotos.com/photos/data/6109/G2.jpg[/IMG]
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| Re: [GMCnet] Ground Confusion [message #133426 is a reply to message #133422] |
Tue, 05 July 2011 16:29 |
pzerkel
Messages: 212
Registered: September 2007
Location: Salisbury, IL
Karma: 0
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Senior Member |
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| Mr ERFisher wrote on Tue, 05 July 2011 15:35 |
there is typically a cable already there, from the engine battery to the
frame somewhere.... usually a bolt near the radiator bottom.
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Apparantly that cable is missing on my coach, which I think is what is causing me the greatest deal of confusion. I am assuming that I can thank a PO for this cable not being there now.
Just wondering, is it possible mine is different because it is a '78?
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)
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| Re: [GMCnet] Ground Confusion [message #133468 is a reply to message #133425] |
Wed, 06 July 2011 01:07 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| Don A wrote on Tue, 05 July 2011 13:55 |
... But does this wiring rearrangement prevent use of the house battery with the boost switch.[?] ...
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You are most likely looking at picture of the battery with the side terminals.
Yes, he did move the large wire, that goes to the starter, from the side of the boost switch to the side terminal of the battery. This reduces the number of connections between the battery and the starter.... a very good thing.
BUT... if you notice the battery also has TOP terminals. The top terminal is STILL connected to the boost switch. You can still get the power from the house battery to the engine side.
If you look at the next slide or so, it shows a battery with only top terminals. It has two cables right at the positive battery terminal. One to the starter, the other to the boost switch.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: Ground Confusion [message #133608 is a reply to message #133419] |
Thu, 07 July 2011 02:01 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Take a look at this presentation that I gave to both The GMC Eastern States Rally in 2009 and again at the GMCMI rally last spring.
See if it helps.
http://www.gmceast.com/technical/Burton_Grounding_GMC_Motorhome.pdf
The engine battery Negative cable does not have to go to the starter. It does have to go direct to any suitable bolt on the engine block.
The jumper between the engine block and the frame is a braided strap located on the back of the transmission to the frame. If this jumper is missing or has a bad connection it will NOT cause engine starting problems under normal operation. This jumper needs to be there, but it is mainly used for charging the house batteries from the engine driven alternator and for using the boost function to start the engine.
Take a look at the above presentation. I made a bunch of changes to it last spring for the last rally and I do not know if the one posted is the current one. I can send you the current one off net by email if you want it. Just seen me an email with your return email address.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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