sdvmopar

I am having trouble finding tach signal. Harness and ecu from 02 ss in a rock buggy, ive searched and only could find the tach wire from ecu but my ecu is tucked away and im not taking my entire dash and ecu out to hook up one wire if i dont have to.so my question is what wire on the passenger coil pack plug is the tach wire? I also hqve a autometer sportcomp2 tach and it dont have the standard 4cyl switch option. You hqve to cut looped wires to calibrate for 4cyl mode. But there is a 2 pulse 4cyl mode and a 1pulse 4cyl mode. What pulse do i need?

maxharvard

Most GM setups use the "pink" wire as the exciter wire.

sdvmopar

What pulse do i set it to? 1 or 2 for 4cyl?

maxharvard

Try both and see which one works. Usually on the back of the autometer gauge is a 6 or 8 cyl mode.

sdvmopar

My tach has a blue and brown wire you cut to make it 6cyl 4cyl 1pulse or 4cyl 2pulse. I piggybacked every wire on the coilpack plug and nothing. Only when it was hooked to the green or the red the tach would say its idleing at 100 and when id rev it to at least 4500 it only goes to 350-400 on tach

maxharvard

Well, it looks like you found the correct wire, now it's just a matter of finding the correct setting.

sdvmopar

Couldnt get tach to read right so i ended up pulling wire to pcm pin10 white wire and works now. So i guess the coilpack harness wires are not enough for tach to read from.

maxharvard

Makes sense when you think about it, you were probably only getting half the pulses you needed.

Good job doing it the right way