Fuel pump relay question?????????

[tripnbubbles]

I have a 2002 5.0 GL its a holley 500 2 barrel carbed engine. Im kinda confused not sure if this is correct or not. so here i go i had to rebuild my motor and have it in. so was just going over all my of my wiring and testing everything and got to my fuel pump relay..... and relay tested fine but when i was checking the wiring i would turn on the key and relay would not engage so then i bumpet the starter and it engaged but did not stay engaged i tested the volts from the alt. (green wire) at 2.6 volts and the wire from the starter (orange wire) was 12 volt at the bump of the key. My question is why would the relay not stay on???????? the only thing i can think of is that mabee (and i realy dont know) is that the green(alt) wire becomes activated wants motor is running. Please someone help me with this i do not want to even try to start this motor with all the $$$$ i have dumped into it with out everything being correct. Thanks to all that reply in advance.

 

[Don S]

Re: Fuel pump relay question?????????

The relay will NOT be energised with just the key on and the engine not running. As soon as you turn the key to start, the relay is energized from the ignition switch from the yellow/red wire. Once the engine starts, power is delivered to the relay via the green wire from the alternator.
There are diodes in the system to prevent back feeding the wires.
Here is the wiring diagram for the relay and pump, should make it a bit clearer.

 

[tripnbubbles]

Re: Fuel pump relay question?????????

Thanks so very much Don S. I feel very confident in the fact that all is good then. I was just not willing to guess as i now have so much vested in this. Thanks Again. Also that was a stupid fast reply !!!