2XR95Z28

iTrader: (4)

so i got my 5.3 swap done and started but im getting no signal to my tach, i have it hooked to the white wire labeled tach signal wire coming off the harness so i dont see what the problem could be. the tach has power and ground as the illumination light and the shift light work but its just not getting any signal. i have a test light on the signal wire coming off the harness and im getting nothing on the light at all? im also not getting anything on the test light when im testing the white tach wire coming out right out of the PCM...

can anyone help me here? i kinda need a working tach here asap hahah

LS1MCSS

iTrader: (18)

If you're saying the shift light comes on when you rev the motor, then the problem is in the tach, not the signal.

2XR95Z28

iTrader: (4)

The shift light doesn't turn on when I rev it, it just comes on when I mess with it like I was going to set the shift point...

busta9876

iTrader: (3)

What year is the 5.3, or more specific, the PCM? Most of the 2003+ PCM's will require a resistor on the tach signal wire to 12v+ to ''pull up'' the tach signal.

670 ohm, 1k ohm, should work fine. there's other posts about this and drawing/schematic on how to do this..try a search.

2XR95Z28

iTrader: (4)

i believe the motor is an 01, and im not too sure on the computer, i would have to ask the guy i got it from... It looks like it would be a somewhat newer computer... Not sure though...

2XR95Z28

iTrader: (4)

i ran different power and ground wires for the tach tonight but couldnt start the truck up as it was too late so we'll see if anything different happens tomorrow but i dont think thats it since the white tach wire coming from the computer wasnt giving any signal to the test light?

Thealien

iTrader: (2)

I had to do the pull up resistor to get mine to work at all and even then it read wrong. A local tuner changed something in the program and it now reads correctly but I still needed the pull up resistor.