starter issue
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From: Honah Lee
Road Master
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From: Annemasse (border of Geneva-Switzerland) facing Mt-Blanc.
Please correct me if I'm wrong:
Assuming both battery lugs are tight and clean, has anyone tried to measure residual voltage between the battery (or tender connections) and the engine block when the starter motor engages ?
A poor engine-to-ground connection will make the polarity of the engine block become "temporarily" positive (+) as the starter motor relay is activated and allows to draw too much current through the resistive engine-to-ground connection.
If the positive lead is "open", the starter motor will simply not turn but the relay can be activated.
Assuming both battery lugs are tight and clean, has anyone tried to measure residual voltage between the battery (or tender connections) and the engine block when the starter motor engages ?
A poor engine-to-ground connection will make the polarity of the engine block become "temporarily" positive (+) as the starter motor relay is activated and allows to draw too much current through the resistive engine-to-ground connection.
If the positive lead is "open", the starter motor will simply not turn but the relay can be activated.
Last edited by Expat1; Apr 7, 2014 at 02:59 AM.
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Joined: May 2008
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From: South Carolina
Please correct me if I'm wrong:
Assuming both battery lugs are tight and clean, has anyone tried to measure residual voltage between the battery (or tender connections) and the engine block when the starter motor engages ?
A poor engine-to-ground connection will make the polarity of the engine block become "temporarily" positive (+) as the starter motor relay is activated and allows to draw too much current through the resistive engine-to-ground connection.
If the positive lead is "open", the starter motor will simply not turn but the relay can be activated.
Assuming both battery lugs are tight and clean, has anyone tried to measure residual voltage between the battery (or tender connections) and the engine block when the starter motor engages ?
A poor engine-to-ground connection will make the polarity of the engine block become "temporarily" positive (+) as the starter motor relay is activated and allows to draw too much current through the resistive engine-to-ground connection.
If the positive lead is "open", the starter motor will simply not turn but the relay can be activated.
If the ground connection is poor, it is simply a poor electrical connection.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,688
Likes: 6,473
From: Honah Lee
Please correct me if I'm wrong:
Assuming both battery lugs are tight and clean, has anyone tried to measure residual voltage between the battery (or tender connections) and the engine block when the starter motor engages ?
A poor engine-to-ground connection will make the polarity of the engine block become "temporarily" positive (+) as the starter motor relay is activated and allows to draw too much current through the resistive engine-to-ground connection.
If the positive lead is "open", the starter motor will simply not turn but the relay can be activated.
Assuming both battery lugs are tight and clean, has anyone tried to measure residual voltage between the battery (or tender connections) and the engine block when the starter motor engages ?
A poor engine-to-ground connection will make the polarity of the engine block become "temporarily" positive (+) as the starter motor relay is activated and allows to draw too much current through the resistive engine-to-ground connection.
If the positive lead is "open", the starter motor will simply not turn but the relay can be activated.
But if it's loose, it can heat up the connection.
Last edited by Jackie Paper; Apr 7, 2014 at 07:31 AM.
Road Master
Joined: Jun 2010
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From: Annemasse (border of Geneva-Switzerland) facing Mt-Blanc.
I was proposing to put a voltmeter between battery and engine block (which is equivalent to starter ground).
In the example shown on the video I would measure 4V instead of 0V with a perfect connection.
Since most of us use battery tenders and have clean battery connections, this could be a two minutes diagnostic
Extreme HDF Member
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From: Phoenix '53, '88, '09 Big Twins
they can be replaced if they go bad, which may happen but is unlikely.
the response up above was an attempt at humor.
Expat, a quick check for voltage drop is a part of diagnosis.
Good that you brought it up.
on many early rubbermounts, there is a ground strap between the inner primary and frame- if that failed or the bolt fell out...the clutch cable would become the new ground...sometimes leading to the cable covering melting, or smoke coming out of it.
Mike
Last edited by mkguitar; Apr 7, 2014 at 12:29 PM.
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From: Honah Lee
The example shows 10 V on the battery and 6 V across the starter. The missing 4 V are converted into heat in one or more connections.
I was proposing to put a voltmeter between battery and engine block (which is equivalent to starter ground).
In the example shown on the video I would measure 4V instead of 0V with a perfect connection.
Since most of us use battery tenders and have clean battery connections, this could be a two minutes diagnostic
I was proposing to put a voltmeter between battery and engine block (which is equivalent to starter ground).
In the example shown on the video I would measure 4V instead of 0V with a perfect connection.
Since most of us use battery tenders and have clean battery connections, this could be a two minutes diagnostic
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Road Master
Joined: Jun 2010
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From: Annemasse (border of Geneva-Switzerland) facing Mt-Blanc.
When you see AC voltage or AC modulation in a DC circuit this means the AC source is less resistive or "stiffer" than the DC circuit that is being perturbated.
If a single diode (rectifier) inside the voltage regulator becomes short circuited you will see the AC pulse across the most resistive component in the circuit.
The only idea behind my post was to inform the younger folks that there are ways to preserve our earnings. If they read this thread they may have learned something and the OP has a partial answer to his query.
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Joined: Mar 2010
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From: Honah Lee
Just tell them it will cause hair to grow on their palms...That's what they told me.