Coil wiring

fearsom · Dec 27, 2011

Is there any way to test or figure out which is the wire that goes to the positive side of the coil. It took the coil off my COBRA to test my GT car. When I went to put it back on I realized that I did not mark wires. When I extended the wires from the MSD box I did not use different colored wires. Now I can't tell which one is positive or negative. I can trace it back but it will take some time. Is there a easy way to figure this out. Thanks

Mark IV · Dec 27, 2011

Turn ignition "ON" and use a voltmeter to test.

fearsom · Dec 27, 2011

So are you saying that with the key on the positive wire will have voltage and the neg. wont.

Mark IV · Dec 27, 2011

fearsom said:
So are you saying that with the key on the positive wire will have voltage and the neg. wont.

Yup! The positive lead will be "live"

toy264 · Dec 27, 2011

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ontVertAlignInTxbx/> <w:Word11KerningPairs/> <w:CachedColBalance/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]-->Old school test: Connect the coil wires, realizing that Murphy's Law (Given a 50-50 chance, you loose) will prevail whichever way you do it. Pull off the distributor end of the coil to distributor wire, and have someone crank the engine. Hold the end of the wire close to the block and move a pencil point into the spark. The graphite will let you see which way the arc is jumping. If it jumps from the block (ground) to the wire, the coil connections are reversed.
My experience has been that the engine will run either way, but someone else will have to explain why it makes a difference, which it evidently does.

Coil wiring

Jim

Rick Muck- Mark IV

Jim

Rick Muck- Mark IV

John Fitzpatrick

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