Looking for the trigger wire for LS-3

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Feb 8, 2013 | 11:11 AM

The Corvette Kid

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Looking for the trigger wire for LS-3

I have a ls-3 in my 61 Corvette with a GM harness and I need to find the trigger wire on one of the ign. coils to power my Speedhut tach. There are 4 wires to each coil harness, does anyone know which one is the trigger wire. my tach is programmable so all I need is the trigger wire from one ign. coil. For some reason it won't read the tach signal from white tach wire on the ecm. Thanks, Bob

Feb 8, 2013 | 11:56 AM

wait4me

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From: warsaw, in

Pin c on the coil is usually the right one.

Feb 13, 2013 | 05:20 PM

The Corvette Kid

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How do I know which one is pin C on the coil, is it marked. Thanks, Bob

Feb 13, 2013 | 06:32 PM

85MikeTPI

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From: Newark, DE

What ECM are you using? The E38 ECM is tried/tested to power factory and aftermarket tachs with some settings and a pull-up resistor.

http://www.hptuners.com/forum/showthread.php?t=36611

IMHO, stay away from cutting coil wires. I've seen several systems code when trying to tap them for a signal.