2003 1500 hd silverado
Hello all,
I was having trouble accelerating (6.0) approx. 215k miles. When throttling (half or more throttle the engine seemed to want to stall) my truck seemed to be starving for fuel. Truck stopped running a block away from home and I was able to start it and limp back into the driveway. I did a pressure test and was only getting roughly 20psi. I checked "Prime" fuse and swapped out the fuel pump relay ending with the assumption my fuel pump failed . Assuming my fuel pump was bad, I purchased a new one and installed with the new wiring harness. With all fuel lines disconnected, the pump kicks on when I turn key, however I am not receiving any fuel from the output of the pump. Pictures below include the fuel pump module that was in fuel tank. Please notice there are two female connectors. My truck only had the 4-prong square connector attached. Factory wiring is 1 Smaller gauged black wire, 1 larger black gauged, 1 purple wire, 1 grey wire. Unfortunately, all I have handy is the part# I purchased from advanced auto parts- Part # M312871. I live in the Northern states and my bed is shot .. so yes, i did cut a hole in my bed, hoping for a quick fix. (flatbed coming soon). Anyways, any assistance is GREATLY appreciated. Thank you all for taking your time to read this.. Fingers crossed
Grey wire- reads 12v for a few seconds with key on (as if it's priming) .. Still not getting any fuel with out any of the lines connected.
Purple wire- constant 5v (assuming this is to the fuel guage).

 

Well, one thing is for certain - they sold you the wrong fuel pump. If you only have one electrical connector, your vehicle does not need the fuel pump assembly with the fuel tank vapor pressure sensor. You need the Delphi Fuel Pump part number FG0271.

If the top of the fuel pump you removed looks like this:
https://www.rockauto.com/en/moreinfo...=10147&jsn=500
they sold you the wrong fuel pump and you need a fuel pump without the fuel tank vapor pressure sensor (Delphi FG0271). Since you got a Carquest brand fuel pump, the part number for the correct fuel pump is M3246728.

Now, if the top of the fuel pump you removed looks like this:
https://www.rockauto.com/en/moreinfo...=10147&jsn=501
then they sold you the correct fuel pump.

I do not know if there are any other differences between the two fuel pump assemblies, but I definitely would get the correct fuel pump for the vehicle before doing anything else.

So, the first step I would take is to get the correct fuel pump.

Replace it and then let us know if you are still having problems.

Good Luck!