Cumminsman01

Hey guys. New to the forum. Been looking through numerous threads in search of the info I'm looking for. Just did the carb swap on my 2000 Silverado 1500. Running the msd 6ls with Victor jr intake, holley 770 street adventure, speed engineering long tubes, comp cams ***** thumpr cam with PAC 1218 springs. Truck runs good and idles amazing. Swapped over due to the passlock II kept leaving me stranded and dealer could not figure it out. Anyhow the issue I'm having now is that my tach isn't working properly which I believe is needed for the 4l60e to function properly. I just ordered the holley tps kit for it so I will have the correct tps signal and voltage the pcm needs but read it also needs the CPS to shift proper too. I ran the yellow tach wire off the msd directly to the back of the cluster and tied it into the factory white tach signal wire. The tach now works but it is double the actual rpm. Can anybody tell me how to get the factory tach to work properly and feed the pcm so my trans will work right? Its wanting to take off in second and has no overdrive. I was wondering if I needed to splice in the cam or crank sensor wires back into the factory harness or if the pcm got it's info from the green wire on pass coil pack harness? Any info would be appreciated. Thanks

Cumminsman01

Got it figured out. Pcm has to have crank position sensor signal. I tapped the 6ls crank harness signal wire into the factory crank sensor signal wire. Tach works perfect and trans takes off in first now and has overdrive and lockup.