I am a wits end. Had a P0001 code. High pressure fuel sensor open circuit. Did fuel rail pressure test. fail. Put in new fuel pump. Have voltage to tank for pump and sensor. Now have P0001 code Fuel volume regulator solenoid open circuit. Replaced pump, high pressure fuel sensor, fuel filter, updated spider injector system (CPFI to MPFI) new plenum gasgets. Have spark to all plugs. checked cam sensor good. Now only getting 42lbs on fuel rail which is not high enough to open poppets. It is a Precision brand fuel pump from O'reileys. Last new pump only had 32lbs. They warranteed it and this one is not doing the job either. Am I missing something? or is it another bad new fuel pump? Also, There is no Fuel volume regulator on a Blazer. Been to GM dealer and we went through all the fuel system looking for it. Only a fuel pressure regulator on back of the spider and it's new with the spider. Blazer driving me nuts! I really need help. Last issue I had with it I had replaced the distributor, ICM, coil crank position sensor, Has new battery. new starter, new radiator, new water pump. replaced upper intake manifold gasgets. HELP!!

 

You need a minimum of 52lbs to open injectors. Sounds like pump again. Yuo should also stick with ac delco ,,,