**IF** your chip has been written for standard fuel pressure, then

- Disconnect the vacuum hose from the fuel pressure regulator
- Block the end of the pipe you have just disconnected
- Measure the fuel pressure at idle speed - this should be 3.5 bar

The vacuum pipe causes the fuel pressure to increase as the boost increases - if the boost is 1 bar, the fuel pressure will be 3.5+1.0=4.5bar, if the boost is 1.3bar, the fuel pressure will be 3.5+1.3=4.8bar (if your chip has been written for standard fuel pressure at idle)