IVECO CLOSE PROBLEM 2.3 HPI

Hello friends, I have a problem with the Iveco, it starts the 2 seconds stop, we have purchased pressure, injectors, regulator and compression of pistons and everything is well !!!!, the fact is that when it opens one of the injectors or the nut of the tube of the entrance of the Common Rail, the truck starts !!! With which we assume that it is pressure and problem in the high pressure pump. Can anyone help me?