Hi 3+3
The power to the mechanical pump keeps the shutoff open while you have power.Killing the power is your engine shutoff.
What injection pump did you get for the truck?
The military pumps have a 24V shutoff.
90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews