flanders

I'm using 492cc at 3bar (43.5psi) injectors and got some troubles with duty cycles being to high.
I've kept cranking up the fuel pressure but it didn't really seem to do much, even though they should flow 564cc at 4bar (58psi).
Important to note is that this is on E85 pump fuel (when measured it seem it's actually slightly over E90 though).

When I was at the dyno yesterday I set my cam to record the fuel pressure gauge.
Not sure if you can see the dial clearly but at WOT it starts off at 4bar and then dropping down to 3bar close to redline.
https://www.youtube.com/watch?v=JUs7FPUHpIA

My AFR numbers are good right now but I don't like the idea of running on maxed out injectors.
I'm also a bit scared that my pump might be bad or on it's way out, or do you think it's normal that it can't keep up?
If so what would the best and easiest replacement be for me?

flanders

Took my pump out today and didn't find anything that looked unusual.
Measured a 0.15V voltage drop with an open connection which seemed kind of normal, would have liked to measure with the pump running but really hard when everything is sealed.
Anyways I've ordered a Walbro 255 now, hope it will solve my problems and that the tiny stock wiring is enough.

The metal tab hanging kind of free in there got me wondering but I guess it's just a grounding for the fuel.


Enough dirt to change? I hope the Walbro filter fits.

flanders

Walbro installed and seems to be working great
Just need to adjust my tune now, got way to rich in the higher rpm's
http://www.youtube.com/watch?v=8Iz70LTG1uQ

proracer07

Nood question, but what will happen if you run a different fuel pump while your car is completely stock?

flanders

The fuel pressure regulator should just pass the additional fuel flow back to the tank.
If you use a really high flow pump it might max out the fpr but a Walbro 255 or similar shouldn't cause any problems.

proracer07

Ah got it, I just don't wanna be running rich or put and stress on the stock injectors

Memo6453

what about for 2006+ S2k's with returnless fuel?

flanders

I think it has some kind of in tank fpr so should also work with slightly higher flow pumps.
Someone with more knowledge about later models could maybe confirm.

Garrett_si

when changing for an aftermarket fuel pump you have to make the fuel pump rewiring with 12 AWG, when no done, you pump voltage drop and the flow suffer

the stock FPR has a to small output for those pump

flanders

Stock wiring is fine for a Walbro 255, it doesn't have that much higher current draw than stock.
But sure it's always good to upgrade the wiring, especially if you are using higher pressures.