Tach Signal

[Ugliergolem]

I have a stand-alone transmission controller for a 4L80E on an 87 chevy with the 350. The controller for the transmission has a wire for the tach signal that I connected to the pickups tach signal wire off the top of the ignition coil, but when I connect it the pickup won't start and when it's disconnected it starts and when it is running it shuts down like its grounding out. I've looked at all the ground points and they all look good. I've also changed out the ignition coil and distributor. What could be causing this that I am missing?

 

[bucket]

So you tapped into the wire that leads from the pickup coil to the ignition coil? If so, that is the issue. For tach signal, use the white wire on the other connector on the ignition coil. It should just be a short wire with a connector on it.

 

[Old77]

So you tapped into the wire that leads from the pickup coil to the ignition coil? If so, that is the issue. For tach signal, use the white wire on the other connector on the ignition coil. It should just be a short wire with a connector on it.

sorry to bump an older thread but I want to get clarification because I was searching the forum for this answer. Andy, are you saying the tach signal comes from that connection I circled in red? The white wire seems to come out of the distributor into connector 1 and out of connector 2. I’m installing my Dakota Digital gauges and want to make sure I understand you correctly

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[bucket]

Yep, that's the tach signal connection.