Where do you guys hook up your tach wire too on your ls1 conversions.

 

Tach output from the PCM. Put the tach in 4cyl mode and you should be set.

Looks like the red connector, pin 10. (PCM Pinouts)

 

Thanks matt i tried connecting to pcm 10 and it didnt work,didnt know it wqs for 4 cyl setting ill do that tomorrow thanks.

 

Yup. LS1=4 cylinder!!!

 

Matt.Well no good,i have dip switchs on my tach and set it for 4 cyl mode and nothing,it worked before on the tpi motor so i know the tach works,so i gave it to a friend of mine to test it on his car to be sure,if not ill have to check the white wire and see if i have any signal coming from it.Sucks i had to take the dash completely apart again.

ok he called me back and my tach works so its the signal from the pcm,ill have to test that now and see.

 

There's actually 2 dip switches. They need to be set to 4 cyl 2 pulse, which on my gauge meant both switches are set in the bottom position.