Fuel pressure regulator sanity check

[ottawa coupe]

So, in relation to my vacuum post...

My s6 has a vacuum of 0.5bar at idle and a 4bar pressure regulator.

This means that the fuel rail pressure should be 3.5bar above atmospheric pressure right?

I have 60+psi rail pressure (above atmosphere) at idle. I have someone arguing it's not bad as it should be 58 (4bar). I think it should be 50psi (3.5bar) and hence contributing to my rich condition.

Edut: with vacuum reference disconnected (open to atmosphere) rail pressure is 4.6bar. Confirmation that i have too much pump?

[Jaswan]

I may be wrong but...

deleted because I probably am wrong!


Jase.

[Tom_]

Adjust your fpr to 3bar when engine is off, only pump running to see the pressure and then when idle you should have 2,5 bar of fuel pressure and with 1bar boost 4 bar fpr.
I dont see any point to have more than 3 bar of fpr, when engine is off , only fuel pump running.

[ottawa coupe]

There is no adjustment at the moment. Stock 4bar fpr installed.

That said, your math is the same as my math in terms of what it should be doing.

I've got one last test to run today then chatting with the vendor to see which way is the way fwd, a different fuel rail/fpr setup that can return more fuel to the tank and reduce rail pressure or a less powerful pump.

[sal_s2]

On my car, at idle the fuel pressure gauge shows 4 bar and increases with boost. It never goes below 4 bar

[sal_s2]