Fuel pump and pressure reg

[soxnail]

Just a little data gather for any one interested...
There are two graphs, one for a static test of fuel pressure vs map without the car running. I have also included what the expected numbers would be for a 2.5 bar and a 3 bar Fuel pressure regulator.



The second one is from an actual run.



Looks like the resolution is not working will re post. My regulator seems to fall in between the 2.5 and the 3 bar...it is supposed to be a 2.5 just recently installed.

Edit: Cannot get the pics to upload in the correct resolution. The line at the bottom is the MAP, the next line up is the theoretical 2.5 bar regulator, the next line up is my current (supposedly 2.5 regulator). The top line is the theoretical 3 bar regulator line.

The reason for the post is that my car is going into lean fault at about 14.5 psi boost, the fault is set to trigger if the afr goes above 13.9 at a boost of 5psi or more.

The next chart (next post) shows this happening. The orange line is the fault, it triggers at where the red vertical line is. At that point the throttle is still wide open yellow line, boost is around 14.7 psi gray line and the afr has risen above 13.9 blue line.

Question can the 2.5 bar regulator with standard fueling parameters support boost above 13 or 14 psi?

Also as the chart shows that the car is running slightly rich at regular (non WOT) settings. Which would make sense as my regulator is running more like a 2.8 bar.

A lot of jumbled info here...will elaborate as needed.
Graph in next post.
Thanks
Sox

[soxnail]

[kdjones2000]

Why are you trying to run such high boost with a 2.5 bar FPR?

Almost all aftermarket chips require 3.0 FPR, likely to prevent the issue you are describing.

[soxnail]

Keith I was just trying to to see what a standard setup, 2.5 bar regulator, original injectors, fuel pump and no change to the fueling curves allows as far as the fuel delivery capabilities of the car.
Normally I limit it to 12 psi.
Interestingly as I noticed above my regulator is more like a 2.8 bar ?? it is part # 944 110 198 03
Sox

[soxnail]

Fuel delivery test, it was approximately 1200 CC which is well above the 850 CC minimum required. The mark on left is 950 CC and the right is 1200 CC, in case the text is not legible.
So the fuel system passes the pressure test, leak down and delivery tests.
Sox

[soxnail]

The reason I am going thru this exercise is that the car is running a little rich at idle or partial throttle about 13.8 to 14.1.
At 12psi it is running a little lean about 12 to 13. I was used to seeing 14.7 at idle and partial throttle, and around 11.5 to 11.9 at WOT and 12 psi.
Since the car passes the pressure and delivery test, next I am going to see if the location of the O2 sensor which is further down stream then the factory O2 is causing a misread. (Please see my thread on the exhaust rebuilt).
Sox

[nize]

for your fuel delivery test, keep in mind the fuel pressure has to overcome the boost pressure which is why it goes lean at higher boost.

[soxnail]

Nize I understand,
My fuel pressure is staying above 50psi the whole time, now I don't really have a way of testing fuel delivery at boost...the test I have done is out of the maintenance manual and is a static test.
Here is a pic of the fuel pressure vs boost. Yellow is Fuel P and blue is Boost, the y axis is psi in pounds.
thanks Sox

[nize]

it's been a long time since i dug into the fuel pressure stuff. is it possible it's hitting the duty cycle limits?

[soxnail]

Originally Posted by nize

it's been a long time since i dug into the fuel pressure stuff. is it possible it's hitting the duty cycle limits?

Which duty cycle limit ?
Sox

[nize]

if i recall, the injectors have an upper limit.