Is it just me or is this a top secret? I can usually find what I need on the internet but do you think I can find this?

I am trying to diagnose a stalling problem with my A4. I have checked the fuel pressure right at the pump, what should it be? What should it be at the fuel rail?

 

Correct way to check is at the feed line going to the fuel rail.
The stock fuel pressure regulator is a 4 bar (58 psi) regulator. You will see this pressure when the vacuum line going to the FPR is disconnected (with engine running), so that the FPR sees ambient air pressure. If you do not disconnect the vacuum line then you have to account for the vacuum drawing the fuel pressure down, since our stock fuel system is a rising rate fuel system.

 

how do you tie in to the fuel rail to check it?

 

Not really sure what the "correct" way to do it is...
I spliced into the fuel line and added the ECS Tuning fuel pressure gauge, which has barbs on each end.
There is most likely a better way to do, maybe someone else will know.

 

Thats how I was thinking of doing it. Wonder how the dealership mechanics tap into it