electrical confusion

[Pomorza]

Hey guys

Today I replaced the negative battery cable and the starter on my Z. (Gear reduction starte, and it was free.) I started working on my Z I swear that the fuel pressure gauge I have read 0. I have the fuel pump and other things connected via a terminal board directly to the battery. I say this because this is what occured. Everything was unplugged from the battery minus the negative cable (big mistake) I was struggling to maneuver the postive cable into place when I accidentally arched it on the engine (side of the block). Sparks flew I was all sorts of freaked out but ok. Unplugged said negative side of battery and connected everything as it was before. I look over at the FP gauge and it reads 30. I'm confused. The fuel pump was off, there's no way power was getting to it as the terminal board (which has an inline 30A fuse) was not connected to the thing, key was off (locked) and the kill switch on the fuel pump was off. How in lords name could I have fuel pressure? I know its possible I misread the gauge (which is what I'm thinking I did) but can anyone think of a way that I went from 0 pressure to 30 by what occured?

Thanks

Jan

P.S

The car does start and run fine. Didn't drive it as I'm having noise issues (electrical noise) but it does run.

[hr369]

what kind of fuel pressure gauge do you have? aftermarket ones are usually built into the fuel rail and are not connected to anything electrical.

Edited August 10, 2012 by hr369

[5thhorsemann]

What type of pump are you running? A thumper pump that puts out 30 PSI?!? (some)Thumpers can run with + & - reversed.

[Pomorza]

The fuel pressure gauge is a standard mechanical gauge that's positioned right after the fuel filter. The fuel pump is a stock 280z pump thats new. (i bought it from MSA about a year ago maybe).

Thanks

Jan