Wont start

[ol'6.0]

I got a 04 F350 with the lovely 6.0 that i can not get to start. about a month ago i saw some wires that rubbed through and wired them back together and it started beautifully and ran great. Than all of a sudden one day it was running like junk. you could push down the pedal and there would be a hesitation and take a while to get going but once it did it would throw you back in your seat. it normally doesnt blow black smoke but when it hesitated it did. i had a guy come look at it and he hooked up his laptop to it he said everything looks perfect with everything that is showing it should start right up. i took my dads ficm and put it in mine and it still didnt start. that guy who came and looked at it brought a new one programmed it to my truck and it still didnt start. could the wires i fixed have a bad connections or something? all that is done to it is a afe intake fass fuel system(less than a year old) and a bullydog PowerPup. head gaskets have been done also. Looking for any ideas. Might try taking fass system off and putting old one back on? I just bought this truck from my dad in December and it ran great than. Love the truck but ready to throw in a cummins!

[dannyboy950]

If you had 1 chafed spot there may be others (a common 6.0 problem), or one of your splices may have come loose.
You can try wiggleing the harness while a helper tries to start the truck, if it starts you have a wireing issue or loose ficm plug.

[ol'6.0]

i tried pushing the connectors in on the ficm and it still just cranked over but i will look around for other wires that rubbed through.

[strokemyego]

could be unrelated issues. icp okay?

[ol'6.0]

for the icp i tried unplugging it and starting it and it did not make any difference.

[strokemyego]

if the icp system has a leak in it, then unplugging the sensor will not make the icp system fixed. unplugging the icp tests the icp sensor, not the entire system. what i'd recommend is finding out what you icp pressure is while cranking. under 500 psi and you have a leak.