[ahh911]

Looks like 090 wur.

I have the same one, took the warm control pressure from 3.4 to 3.6 bar, didn't notice much difference. My notebook is at home..

How was this test quickly performed without knocking the big round thing up or down? To increase the warm control pressure I simply placed a small shim made up of beer can tin under the spring if I remember correctly. How did I lower it? I placed shims between the wur case halves, made of beer can tin stacked on top so I could increase the range in steps. Got all the range I needed to test how the car would respond and used a fuel pressure gauge of course.


Edit:
For what it's worth, I have my notes in front of me now:

System: 5bar.
WCP with 0.3mm spacer between wur case halves 3bar
WCP with 0.2mm spacer between wur halves 3.2 bar, My notes are barely understandable but I did write, 2000 to 3000 rpm surge. 02 sensor ~ 58% (probably increased 8% from 0.3mm)
WCP with 1 shim, 0.1mm, 3.3 bar. FV duty average moved from 58 to 67% (reset mixture to 50% before next step).
WCP with no shim, 3.4 bar, O2 duty cycle went from 50 to 57%.

These notes are hard to decode, so I wouldn't bet on the above being 100% accurate, but we can see that the o2 system is jacking up the fuel as the WCP is increased, by about 8% per 0.1mm.

In my notes, I wrote that 3.2bar to 3.4bar made little difference, maybe at high rpm. I went higher control pressure but wasn't interested in that.
I don't think 3.4 or 3.5 bar is going to matter once the mixture is set correctly, but I can't be sure. Have you checked your gauge calibration? It's easy to be off 0.1 bar.

Phil