MSD 6A Tach Problem
Thread Starter
Heel & Toe
Joined: Sep 2001
Posts: 16
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MSD 6A Tach Problem
Just hooked up a MSD 6A ignition on my '94 LT1 and it works fine, but the tach starts to wander above 3000 rpm and the "Service ASR" light stays on. I'm also not getting a tach signal from the MSD tach output terminal. I called MSD and they told me to bypass the factory inline tach filter which they say is a little round filter that has a single white wire passing through it and is located behind the left cylinder head by the intake manifold. I looked all over that area and could not find it anywhere. Does anyone know exactly where the tach filter is located on the LT1 engine and if this is indeed the solution to my problem? Any help would be greatly appreciated. Thanks!!
Le Mans Master
Joined: Oct 1999
Posts: 9,713
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From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: MSD 6A Tach Problem (vette4kjl)
Follow the injector harness. The tach filter is next to the coil in the harness. It is a small box about 3/4" x 1 1/4" and will be wrapped in tape in the harness. It has 3 wires connecting it into the harness, 2 white wires and one black wire. Cut the two white wires and splice them together. I left mine long enough off the filter to wire it back in if I needed and I left the black wire attached (ground) and simply tapesit back into the harness.
