Turning Engine Over with Fuel Pump Relay Pulled?
 

Greetings!

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

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!

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 :)

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

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

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.

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.