Here are the three things I would check first, check the power or ground connections at the battery, the IDM and ECM power source make sure they are all clean and tight, closely check all the fuse links on the hot side check for corrosion or melting on all of these connection points check the connection points on the small wires on the ground side also this is where the ECM and IDM ground repair as necessary these issues are widespread on these international trucks if all that checks out next, I would begin an electrical diagnosis with a scan tool. I'm assuming you don't have one, so in your case, I would first replace the cam position sensor CPS international part number 1885781C91. If the truck still won't start next, I would check the ICP sensor and high-pressure oil system check for any oil liking into the connector try to start the truck with the ICP sensor unplugged if it starts, the ICP sensor Is defective and needs to be replaced if there is oil in the connector the ICP sensor
and pigtail need to be replaced as a pair the ICP sensor is located on the high-pressure oil gally this is on the driver's side of the head it has a three-wire triangular connector. If all this checks out, it's time to dive deeper into the high-pressure oil system. First, check the oil is full and in good condition, meaning 15w40 within regular service intervals. Next, check the low-pressure system. You will need 8psi while cranking to start if less than 8psi could have a bad oil pump or worst case main and rod bearings. If that checks out, move to the IPR valve, remove it from the hpop check for blown o-rings or metal debris. If debris is found, the hpop and IPR valve must be replaced if the o-rings are blown, this can be repaired with Alliant power service kit AP0003, but if the IPR valve is original, I would replace it with a new one. If all this checks out next, I would check for oil in the fuel. If oil is found in the fuel you will need to replace your injector O-rings.
hope this helps. Thank Jonny