heavy85 Posted March 14, 2008 Share Posted March 14, 2008 I hooked up the white 'tach' wire from the PCM to the Autometer. Tach was working fine with the L6. Cut both wires on the back of the tach to make it 4 cylinder. I get nothing - no needle movement at all. From LS1tech forum I tee'd a 480 ohm pull-up resistor (from 12v source ... actually tee'd into the tach power wire) into the signal wire and still nothing. No movement at all. I know it's getting power and ground as the gauge light comes on and the power & light wires are spliced together. Also verified there is continuity from the gauge green signal wire to the white PCM wire. Any suggestions or ways to diagnose? Thanks Cameron Quote Link to comment Share on other sites More sharing options...
janaka Posted March 14, 2008 Share Posted March 14, 2008 on the back of my AM tach there are switches that you have toggle to be in the right position for a V8, 6cyl or 4cyl... i know that both have to be in the "up" position for V8 (4pulse), both down for a 4cyl (2 pulse) and first down, second up for a 6cyl. (3pulse) Is yours set up properly? Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 14, 2008 Author Share Posted March 14, 2008 on the back of my AM tach there are switches that you have toggle to be in the right position for a V8, 6cyl or 4cyl... i know that both have to be in the "up" position for V8 (4pulse), both down for a 4cyl (2 pulse) and first down, second up for a 6cyl. (3pulse) Is yours set up properly? Mine is old so there are no switched there are wires you cut. One is orange the other brown. You cut both for 4 cyl and mine are both cut so yes it's set-up right. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 18, 2008 Author Share Posted March 18, 2008 Anyone? Can't calibrate the G-tech ... or know when to shift ... until I fix this stupid thing. I'm hooked to the white wire ('02) and I get nothing. I realize it's a frequency but so should read average voltage (~9V from what I've read) but I get nothing. Anyone know if there is some type of fuse or something maybe I dont have hooked up that runs the Tach out ... kind of like the back-up light +12V that you have to feed the PCM? Thanks Cameron Quote Link to comment Share on other sites More sharing options...
Dudeboy Posted March 19, 2008 Share Posted March 19, 2008 Cameron, I had saw this little diagram and could not remember where I saw it. I FOUND It!!! Street and Performance have a great install and tech pages on LS installs. This may help you: http://www.hotrodlane.cc/New%20LS%20Links%20Page/lstach.html Give them a call they can help you if there not to busy. Quote Link to comment Share on other sites More sharing options...
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