Would a fuel pump re-wire change base fuel pressure?

[614talon90]

I am having an issue with my car leaning out once it hits over 5 psi of boost. Today re-wired my walbaro 255. After I was done with the re wire I started the car and noticed that my bfp changed from 35 with the vacuum line on and 42 with it off, to 40 with the line on and 47 with it off. Should it have done that? I did also re route a few of the vacuum lines while I was working on it due to the fact that the previous owner had everything ran off of the same vacuum line. Would that have changed the bfp?

 

[loco4G63]

As far as I know the basics is the rewire just keeps the fuel pump from dropping. Not so much as in pressure but rather a failure to deliver volume. I could be wrong on this but I would reset it and go from there. I'm at 43.5 on my FPR never noticed any real issues but my vacuum setup is stock run. Save for Fuel pressure solenoid of course, a quick check too is some hair spray across the vacuum lines while running or wd40......anything that can be burned. Anyways a quick light mist across ## vacuum lines and your checking for a rise in RPM. If this happens that's roughly the area of your vacuum leak. It's an old school trick but has always worked for me. Be careful not to spray too much and start a fire : ) FINE MIST !!! Good luck

 

[NHerron]

In theory yes it changes the pumps output, especially when boost is high and fuel pump is outputting it's most flow. When more current passes through a wire, resistance can sometimes show itself if the wire isn't rated for the amperage.

In all practicality, I don't know for sure how much effect this has in real life. But when I did my rewire I readjusted my pressure a bit.

 

[rEclipserGST]

I was under the impression that a fuel pump rewire only keeps a constant voltage. In a sense, I guess it could increase bfp (base fuel pressure). But I can't see how that would change with no power to it.

 

[99gst_racer]

Yes, it can increase base pressure. It's definitely wise to re-check base pressure after a rewire.

 

[614talon90]

Awesome thanks for the info guys. I was just confused as to whether it was the pump or the vacuume lines. Guess that's what u get for changing too many things at once.