Fuel Pump Relay or fuse?

[duduglanza]

Hi,
Does the fuel pump have any fuse/relay in the fuse box? and which one? I have a problem of fuel pressure not stable and decreasing bit by bit while cruising. Could it be electrical problems since i have fitted a new pump and fpr.. also tested my injectors! it's the only thing left to check..

 

[Texx]

I have a problem of fuel pressure not stable and decreasing bit by bit while cruising.

How have you confirmed this? Fuel pressure will decrease in relation to inlet manifold depression, that's normal. A fuelling check using a wideband AFR gauge is the only way to know for certain whether you have a fuel supply issue.

The fuel pressure in the fuel rail with a stock setup should equal approx 2.5bar + manifold pressure, i.e. at 0.5bar boost the fuel pressure should be at around 3bar, when the throttle plate is closed and the manifold depression is at say -0.5bar fuel pressure should be at around 2bar.

When running larger injectors and an adjustable FPR, the fuel pressure should equal approx 3bar + manifold pressure, i.e. at 0.5bar boost the fuel pressure should be at around 3.5bar, when the throttle plate is closed and the manifold depression is at say -0.5bar fuel pressure should be around 2.5bar.