Turning Engine Over with Fuel Pump Relay Pulled?

[Seadweller]

Greetings!

I know it's only Monday, but I have a couple ignorant questions:

1. I see there is both a fuse and a relay associated with the fuel pump. I assume that removing either would prevent the pump from operating? Is one better to pull than the other?

2. Would it cause any harm to turn the engine over for a few seconds with the fuel pump relay or fuse pulled?

Thanks!

[pilot4fn]

After I rebuilt my 2001 2.7 engine past winter, I did remove the fuel pump relay and cranked the engine for a while to prime the oil pressure.
This is the good practice I found to be recommened by fairly well known Porsche engine builers and it worked real well for me

[Seadweller]

Thanks....Will pulling the C-4 fuse accomplish the same thing?

[pilot4fn]

I have no idea. Somebody else can chime in on this.

[JFP in PA]

You really do not need to pull a fuse or relay to do this. We regularly start re-assembled engines by spinning the starter over with the ignition, but releasing the key just before it catches. Do this three or four times, you will have oil pressure.

[Seadweller]

Thanks all....I went ahead and pulled the C4 fuse, and sure enough, the engine would not start, which is exactly what I wanted. My engine fires up the second I hit the key switch, and I wanted to experiment with pulling the fuel pump fuse to turn the engine over before starting it to see if I could eliminate the start-up rattle.

I pulled the fuse, turned the engine over for a couple of seconds, replaced the fuse, started the engine, and the start-up rattle vanished completely. My car can sit for weeks untouched, and that start-up rattle was unnerving. That quick step of turning it over with the fuel pump fuse pulled before starting the engine completely eliminated it.