Low voltage at coil probs help!
Thread Starter
Instructor
Joined: Jun 1999
Posts: 223
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From: New Zealand
Low voltage at coil probs help!
Hi, just swapped out an after market mallory coil for a stock style MSD blaster coil so i can refit my ignition sheilding.
Checked voltage before i started it and very low
The car has an external ballast. The power wire to the ballast has 12 votls until you connect it to the ballast then it has just under 6 volts, and the other side has about 3 volts.
Why does the voltage drop so much (1/2 in fact) when the feed wire is connected to the ballast.
I have tried a new ballast just in case, same problem. Ballast has about 1.9 ohms resistance.
Coil instructions clearly state must be wired with ballast as do the stinger instructions for the dizzy as well.
Help??????
Checked voltage before i started it and very low
The car has an external ballast. The power wire to the ballast has 12 votls until you connect it to the ballast then it has just under 6 volts, and the other side has about 3 volts.
Why does the voltage drop so much (1/2 in fact) when the feed wire is connected to the ballast.
I have tried a new ballast just in case, same problem. Ballast has about 1.9 ohms resistance.
Coil instructions clearly state must be wired with ballast as do the stinger instructions for the dizzy as well.
Help??????
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
Originally Posted by Duke94
I believe you should have 12 volts to coil while cranking and about 9 when running. AT least that's what it was on my 71' with stock points dist.
Last edited by shafrs3; Jan 29, 2006 at 09:38 AM.
Burning Brakes
Joined: Jul 2001
Posts: 853
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From: Foxfield, Co
Originally Posted by big_G
The factory wiring has a built-in ballast resistor. You don't need the second one. Try just running the factory one. (It's part of the wiring harness). 
It sounds like the factory one is still there and you are hooking a 2nd externel one to the end of the wire.
