[SSUNDVL]

First time, I jumped the hpfp fuse in rear of car with the high pressure feed line disconnected, second time I had to drop tank just drove car until fuel level read as low I felt needed. If you are installing an aux pump, your can drive it until nearly out of gas and when you drill the hole, just pull out (lol) the drill before gas starts leaking and you can drain it in a pan.

Just read only swapping lpfp, discard hole comment. When you install the new lpfp make sure all the lines inside are in a good area that will not touch the fuel level sensor. Large hands can make this difficult.

Also when you remove the cap holding the fuel pump, you can use a flat head and hammer to get it off.

[MartinLe]

Thanks

[SFV1LE]

I dont know how the ZL1 fuel lines are routed but... I know that when some turbo sport compact tuners are on a dyno and want to drain all 91 from tank before filling with E85 or other race fuel (or vice versa) they will disconnect the return line from the FPR on that side of the rail on the motor and connect a separate fuel hose there that runs into a fuel jug(s), then let the engine idle while the fuel return flow empties the tank. Not sure how empty you need it to be, you can stop after you're at E for awhile or go until the car starts to sputter. I don't think it's dangerous for the motor, you're under no load or boost at idle. The return flow should be significant.

Again, not sure about ZL1 fuel system so may not work.

UPDATE: I just Googled it and looks like the ZL1 is a returnless fuel system, so my reco won't work.

[MartinLe]

Thanks for the effort.