No power at pump, but has power to relay?
I replaced the fuel pump on a 2001 chevy express and no there is no power at
the pump. We did not have to change out the old wiring harness so I'm feeling a
Note the diagram. The relay has two sides, the switch side and the control side. Voltage for the switch side is fused. Voltage for the control side comes from the pcm. The control side, the right side of relay in diagram, needs voltage and ground. The voltage to switch side of relay is hot all the time, voltage to control side of relay, goes hot with engine cranking. I don't know what all testing you have done? Engine cranking, do you have spark at the plugs, gasoline engine, I'm not sure of engine size? Also, do you have fuel injector pulse? Engine cranking if your missing everything, have to check for rpm signal. If you have narrowed it down to only the fuel system, then we can concentrate on that one system. Any applicable trouble codes?
I have a 1996 Chevy express van with this issue. Been in the shop 3 times for fuel pump problems. The problem was and still is cranks over but won't start. It's had three fuel pumps replaced the computer,and this last time was the fuel pump relay. I have replaced the MAF sensor the oil pressure sensor. It has broke down in front of Texaco now I can feel the relay energized, but no voltage the fuel pump when I turn the key to the on position. It just keeps cranking. No pressure at the fuel manifold. I will definitely be on the phone with my mechanic first thing in the morning.