I am trying to fix a crank no spark issue on a 2001 Silverado with 4.3. I have replaced basically every part of the ignition system that i know of including- new & tested icm, new & tested coil, new cam sensor, 2 new crank sensors, & just put a new pcm that was programmed to the vin & still i have a crank no start no spark condition. Ive checked all the usual stuff fuses all good, power & ground to icm, ic, power at ckp, i wasnt getting continuity between ckp & pcm blue/white wire so i actually added a lil jumper wire from pcm to ckp to see if i got spark & still no spark. When i put led test light on signal wire to icm & crank engine the light does not flash which is why i ended up replacing the pcm but still no spark? Idk what else to check i read a couple things online about some wiring in the ignition cylinder? Idk if that could possibly be part of the problem or not but the truck is actually not mine & its a couple hrs away but they owner is supposed to be having it towed up to my house so i can try to figure it out in my garage. Im not really sure where to go from here besides starting all over from beginning & test everything again to make sure i didnt miss anything? I would very much appreciate any other suggestions or advice. Also my good 400 dollar foxwell tablet style scan too will connect & read & clear codes but when trying to read live data it will connect for a sec then say no communication? Which i know my scan tool works just fine on any other vehicle but my other cheaper launch creader scanner does connect & in the live data it shows no ckp or cam sensor signals? Although when reading engine speed its showing engine rpms while cranking so idk why its showing no ckp signal?