cpu out?

I just swapped my 4.3 for a 350. Had it running (with only headers). I didn't have my o2 sensor hooked up but i cranked it to test it. Ran good. Today i cranked it again and it was fine but i turned it back off. And went to crank it again and all my gauges are reading wrong and i'm not getting a service engine soon light at all? (which i should be). Could the computer be out? I put the 350 prom in the cpu. The guy i bought it from sent me the main prom (the one that goes in the cpu under the plate) and another little chip that i don't know where it goes? Has anyone else ever had this problem? Now the truck won't crank, turns over but wont crank, think its due to the cpu being out?

ok i figured it out.. talked to the guy i bought the "prom" chip from and the 350 cpu takes 2 chips. the 4.3 cpu only takes one. so i'm buying a new cpu for the 350 with the chips in it. hope this does the trick and i hope none of my sensors are messed up. hope this helps someone that does this motor swap if they didnt know the cpu is different, not just the chip. if yall need to know nething else about the 4.3-350 swap just ask. i did it all myself so i can answer any questions. thanks guys

ok the problem didn't get fixed. i recieved the new cpu today hooked it up and its still doing the same thing. when i turn the key on the gauges on the dash arent reading and the SES light will not light (i know it should). When i try to crank the truck no fuel is getting sprayed. Checked the injector wires for power when being cranked and am not getting anything. Checked all fuses and relays. The one thing i found that doesnt seem right is on the cpu i checked the orange wires for power, and 2 have power and one doesn't. But how can i track down this wire without tearing the whole truck appart? Does anyone have a wiring diagram of this truck that will show this wire and where it goes? I have a haynes manual but its not detailed enough on the wiring diagram. please help me figure this out. the truck cranked and worked 5 times and all of a sudden it just stopped working. Has to be a power problem.