Author Topic: check coil to see it works  (Read 9165 times)

Offline Kevin71

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check coil to see it works
« on: May 31, 2015 - 07:22:26 PM »
I connected the large black wire that goes to the alternator to the coil neg.  I have a MSD 6AL and dist.  Realized that was the wrong place and connected to the alt.  How do I check the coil to see if I burned it up.  No fire at the plugs.  Wasn't before when I connected the large black wire either?




Offline mopar jack

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Re: check coil to see it works
« Reply #1 on: May 31, 2015 - 07:45:54 PM »
Use an ohm meter to check the primary side of the coil for continuity. You measure across the negative and plus side to read the resistance.

Offline Kevin71

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Re: check coil to see it works
« Reply #2 on: May 31, 2015 - 09:18:31 PM »
If it is bad I take there is no resistance.  Or is there a minimum

Offline mopar jack

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Re: check coil to see it works
« Reply #3 on: May 31, 2015 - 11:40:51 PM »
If the coil burned a winding I would expect open resistance which would show as infinite on meter. Normal resistance would be 1.4 to 1.7 ohms approximate depending on temperature. 

Offline Chryco Psycho

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Re: check coil to see it works
« Reply #4 on: May 31, 2015 - 11:52:22 PM »
or hook 12v to the + terminal & momentarily connect the - terminal to ground , as you disconnect the ground it should create a spark

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Offline Kevin71

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Re: check coil to see it works
« Reply #5 on: June 01, 2015 - 10:01:25 AM »
Well I am not getting any power to the coil from the msd unit.  I will have to get some wire to bridge between a hot lead and the coil to check the coil or I need a battery for a meter.  Haven't used it in 10 years.  So I am thinking that connecting a wire from the battery + to the - negative side of the coil could have burnt up the msd possibly.  The power light is coming on, on the msd with the ignition on so it should have current to the coil at that point shouldn't it.

Offline Chryco Psycho

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Re: check coil to see it works
« Reply #6 on: June 02, 2015 - 12:27:49 AM »
nope , not with MSD
 so I would go back to hot wiring the coil & breaking the cicuit to make sure the coil is working .
 Maybe the msd is not grounding or ungrounding the coil

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Offline Kevin71

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Re: check coil to see it works
« Reply #7 on: June 02, 2015 - 09:54:52 AM »
I put a ohm meter on the coil.  The numbers were bouncing all over.  It was set at 200 on the ohm meter and I was getting 1.3 to 31.  and constantly changing.  does this make sense?

Offline Kevin71

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Re: check coil to see it works
« Reply #8 on: June 02, 2015 - 08:13:21 PM »
I moved the tester down lower on the terminals and got .9 reading with the meter set on 200.  I got 5 from the positive to the center when set at 20K.

Offline Bullitt-

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Offline Kevin71

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Re: check coil to see it works
« Reply #10 on: June 02, 2015 - 09:26:28 PM »
Would the 5 on 20k translate to 10,000

Offline Bullitt-

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Re: check coil to see it works
« Reply #11 on: June 02, 2015 - 11:18:21 PM »
The way I get it is on the 20k range the reading would look like 10.000 to 11.000... to double check I checked my coil & it read 10.75 which I interpret as 10,750 ohms
To double check I tried an 8ohm speaker which i surmised would read .008....all I got was 0.00 so I lowered the scale to 2,000 & it read 0.08 soooo I think I'm on track   
Wait for Strawdog to weigh in.. he'll set us straight.  :bigsmile:
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Offline Strawdawg

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Re: check coil to see it works
« Reply #12 on: June 02, 2015 - 11:47:35 PM »
LOL...that is the reason I started buying auto-ranging digital meters about 30 years ago...but you are right, Wade :)

Offline Bullitt-

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Re: check coil to see it works
« Reply #13 on: June 03, 2015 - 05:48:52 AM »
LOL...that is the reason I started buying auto-ranging digital meters about 30 years ago...but you are right, Wade :)
Got my first digital meter this year so I'm learning ....dear old analogue finally gave up the ghost
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Offline Strawdawg

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Re: check coil to see it works
« Reply #14 on: June 04, 2015 - 09:08:47 AM »
Got my first digital meter this year so I'm learning ....dear old analogue finally gave up the ghost

Makes chasing voltage drops a lot easier without much thinking!