I believe im dealing with some low fuel pressure issues. the car is boggin under load, and when I cut the fuel with my fuel pump switch the car dies immidietly, it doesnt sputter out like normal.

Anyways, its got a walbro 255 installed. Ive heard about the s4 turbo sytem that changes the pump voltage from 9 to 12 volts depending on load.

I put a multimeter to my pump as the car was running, it read 5 volts. 7 volts when revving the engine a bit.

I assume this is way too low, and thats where the low fuel pressure issues are originating.

does the pump just ned a rewire? or am I dealing with something bigger here.

 

Without good voltage at the pump, it has no chance to make enough flow or pressure.

 

What is the color of the wire you're probing? At the fuel pump plug, right? And what are you using as a ground for the meter?

 

^^good point^^

As long as he's probing the right wire and getting good ground I would say he's just in need of a re-wire.

 

isnt one of the big wires power and the other big wire ground? I was just probing accross them, which would give me the voltage drop accross the pump, which I sort of expected to be 9/12v