swapped 4.3 to 6.0 and not getting spark to one cylinder NEED HELP

[butler145]

just had my 2004 silverado 4.3l swapped out with a 6.0 and all but one cylinder is getting spark. had new heads, intake and cam installed. and installed motor ready to go but looks like one cylinder not getting spark. its got me puzzled. have swapped a coil pack from a cylinder that is getting spark knowing its coil pack is good to the bad cylinder and still no spark. have tried swapping out a whole group of coil packs that work and that same cylinder still has no spark. have tried just swapping spark plug wire still nothing. have tried 3 different computers that did nothing. checked to make sure from the computer to that one coil packs plug makes a circut in the wiring harness and it does so that was ok. just swapped to the wiring harness that came wth motor out for another wiring harness. and that cylinder still has no spark. i dont know what else it could be or where to go from here. any help would be nice so can get back to driving it.

[Bomicheal]

have you changed spark plug just asking

[butler145]

yeah put new ones in when put the motor in. hasnt even left driveway since the swap cause didnt sound right running then when used timing light the one cylinder shows nothing. light doesnt come on.

[butler145]

yeah i will try that and then maybe try checking the grounds. i onno if that would cause it or not. might just get a thick wire to connect to frame good and connect it to motor.

[foggy]

try swapping that spark plug to another cylinder, that will let you know if it is a bad spark plug.

[butler145]

yeah true i will do that tom and see if that spark plug works.

[pei_sierra]

not sure if you have found the problem yet but One truck i had worked on before had no action from one coil. these coils use battery positve, pcm control and also the low reference signal. it can full you checking the low reference because it wont light an ordinary test light if checking. you need a meter to see if its getting voltage there. im guessing you already knew that, just thought id throw that out there.