eyft23

hi.. I have a brand new LS3 w/ 6L80 trans from speartech.. I am currently using the Autometer #1379 & 1390.. I was wondering if anyone can help me out here.. My tach only works while it is in the park position and not while driving, and my speedo only goes up to 10mph.. I double checked the wiring to make sure I hooked it up correctly.. For the tach I made sure it is calibrated for an 8 cyl.. I am wondering also if I calibrated the speedo correctly and that is why the tach isn't working correctly? Am I using the correct gauges? Any help would be greatly appreciated. Thank you..

85LSXTRUCK

iTrader: (2)

My tach said to set it to 4 cyl for ls engines, worth a shot. I am still having trouble getting my tach to work. i am trouble shooting right now.

jetlag

iTrader: (32)

Yeah that's what I was going to say. Try setting it to 4 cyl.

eyft23

Oh ok.. I wonder why that would be? I'll try it out when I get home tonight.. Thanks

1964SS

iTrader: (1)

Have you tried the Tach in 4cyl mode? That might fix your issue. Tach signal comes from the PCM and shouldn't matter what position your transmission is in.

Have you marked out a mile and calibrated your speedometer?

eyft23

I am going to try out the 4cyl/2pulse mode tonight when i get home.. yes i have calibrated the speedometer.. if i do get the tach working i will try and recalibrate the speedo also.. thank you very much for your help..

eyft23

sorry for the late response, but I've been having some issues with my wiring to my injectors and I finally got that finished. I tried out the 4cyl/2 pulse on the back of my tach and it still does not work.
the computer and wiring harness is a stock LS3..
does anyone else know what might be wrong, I am still stumped..

1964SS

iTrader: (1)

Have you tried a pull up resistor on the tach circuit? I've read that some need to do this to get the tach to work.

Check this forum link out.
https://ls1tech.com/forums/conversio...magic-man.html

eyft23

thank you very much. I will try it out..

jcvett56

Speartech harnesses already have a pullup resistor on the tach circuit. Make sure you are going to the the signal in on the tach. Then +12v and ground. It should only take those three wires and you are up and running.

For the speedo try calibrating per autometers instructions with the 2 mile marker setup.

eyft23

yes I am running only those 3 wires to the tach and it does not work. I will double check again but I am pretty sure I did it correctly.

I haven't been able to do the speedo but I wanted to get the tach done first.

thank you.