adamscamaro

I have had the LS2 in my 67 RS/SS Camaro for a few years now. I have every single gauge hooked up and working perfectly in my vehicle except for my Tach. I have looked at different wiring diagrams on the internet, tried hooking it up to different signal wires from the ECM, tried switching the Autometer (Carbon Fiber Series) gauge from 8 cylinder to 6 cylinder to 4 cylinder and I can't even get the gauge to move.

First question, can anyone provide me with a definitive answer as to which wire I should be using for the tach signal out of the ECM?

Second question, should the actual tach gauge be set for 8, 6 or 4 cylinders? (Everything I have read has said 4 cylinders since the LS engine is a 2 pulse system, I believe)

Third Question, what would be the best method to get this up and running, a pull up resistor (1K ohm in line, I believe), a tach adapter (Autometer or dakota digital) or another method possibly?

Thank you all for your help, insight and opinions!

TomM

iTrader: (56)

What PCM are you using? What harness? did you do the harness or was it purchased?

T,

adamscamaro

I am using the stock GTO LS2 harness which came with the engine. I had someone go through it and identify the wires I needed to run the engine such as fuel pump, grounds, signal, power, etc.

Thank you for the reply

bmf5150

Read this about what he said about tach


https://ls1tech.com/forums/showthread.php?t=1449731

adamscamaro

Thank you that helps a lot. I just spoke to John at Speartech and he basically said the same thing. He advised me to get a 4700ohm resistor and "T" it into the tach signal wire from the ECM and have it connected to a 12V source. In that thread you linked me to he is using an LS6 and said that he used an 8K ohm resistor. I am going to try the 4700ohm resistor first and see where that gets me. Thank you again everyone for all the replies. Hopefully I can finally get this tach hooked up.