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Evred
Samba Member
Joined: October 27, 2020
Posts: 1
Location: California
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 Posted: Tue Oct 27, 2020 11:44 pm Post subject: No spark from coil |
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| I have a buggy and I’m trying to get spark from the coil by taking plug off dist cap and arc it to ground but I’m having no luck. I have a new coil so I assume that’s not it. Right now I am trying to bypass the ignition switch by jumping the coil to the battery just to see if it’ll start but that also gives no spark. Is there something I could be missing? From what I’ve gathered the coil just needs 12v power to be able to test For spark right? |
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Cusser
Samba Member
Joined: October 02, 2006
Posts: 31362
Location: Hot Arizona
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| Posted: Wed Oct 28, 2020 7:01 am Post subject: Re: No spark from coil |
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| Evred wrote: |
| From what I’ve gathered the coil just needs 12v power to be able to test For spark right? |
Needs that 12 volts positive at coil terminal #15 and the points to be opened and closed, and the distributor wire going to coil negative terminal #1.
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MrGoodtunes
Samba Member
Joined: May 14, 2012
Posts: 852
Location: South Florida
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| Posted: Wed Oct 28, 2020 9:00 am Post subject: Re: No spark from coil |
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| Spark should jump just microseconds after 12 volts drops to zero across coil input terminals. Assuming you do indeed have a hot 12 volt source connected to (+) terminal on coil, the problem may be that you do not have the (-) terminal grounded. Ideally, it would be grounded thru the points. But points might be open; or even if closed, might not be passing electrons. |
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mukluk
Samba Member
Joined: October 18, 2012
Posts: 7023
Location: Clyde, TX
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| Posted: Wed Oct 28, 2020 9:57 am Post subject: Re: No spark from coil |
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To test your coil using only a fully charged 12V battery:
1. Connect the coil positive or "15" terminal to the positive post of the battery.
2. Connect a wire to the negative terminal of the battery only -- this will be your coil trigger wire.
3. Install the high tension lead into the center post of the coil.
4. While holding the free end of the coil high tension lead approximately a quarter inch away from the battery negative post, take the free end of the trigger wire that is attached to the battery negative post and briefly touch it against the coil's negative or "1" terminal -- the coil should spark as soon as you pull the trigger wire away from the coil's negative or "1" terminal.
For a bit more information on ignition systems, see the following link: http://www.secondchancegarage.com/public/122.cfm
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ashman40
Samba Member
Joined: February 16, 2007
Posts: 15982
Location: North Florida, USA
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| Posted: Wed Oct 28, 2020 12:21 pm Post subject: Re: No spark from coil |
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| mukluk wrote: |
| 4. While holding the free end of the coil high tension lead approximately a quarter inch away from the battery negative post, take the free end of the trigger wire that is attached to the battery negative post and briefly touch it against the coil's negative or "1" terminal -- the coil should spark as soon as you pull the trigger wire away from the coil's negative or "1" terminal. |
mukluk's directions are perfect.
I would just highlight the key point he made, that the ignition coil will trigger a spark when the #1 terminal wire is removed from the coil, not when it is connected. This is not intuitive and catches some off guard.
Completing the electrical circuit thru the #1 and #15 terminals "charges" the coil by creating a magnetic field in the primary winding. When the #1 wire is disconnected (or points OPEN) this field collapses. This induces current in the secondary winding (larger HT center wire) which results in the discharge of a spark.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road  }
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'67 Beetle #2 {2019 project car - Wish me luck!} |
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meranda
Samba Member
Joined: August 09, 2015
Posts: 277
Location: Melbourne Australia
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| Posted: Thu Oct 29, 2020 5:51 am Post subject: Re: No spark from coil |
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Just don't do it just after you have charged you battery or the fuming hydrogen will cause an explosion. Just ask my why I know!!
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