What Fuel Pressure?

Quick one for ya, What fuel pressure should I be getting at the rail with the engine at tick over and with the engine off? I believe you can use a normal tyre pressure gauge (once) is this true?

with the engine off, not much lol. engine at idle is hard to say as well as it will depend on rpms etc. The correct way to check rail pressure is with the vacuum feed to the pressure regulator pulled off and plugged, or just stick your thumb over the end, kink the pipe 180 degrees to close it etc. Then there will be a manufacturers figure for base fuel rail pressure that should be achieved at this point. Normally it's around 3.0 bar but there will be a specific figure for the car. if the vaccuum pipe is left connected it will vary the fuel rail pressure so you can't tell, for example given a base pressure of 3.0 bar, when I am at full boost in the Rover, just shy of 1.4 bar, then the actual fuel rail pressure at that point is getting on for 4.4 bar, at the same time, at idle theres a vaccume, ie -ve manifold pressure, of 9psi, so thats roughly 0.6 bar IIRC, in that case the rail pressure would be 2.4 bar at idle if the vaccuum pipe was left on. Ross Ross

regulated fuel pressure should be 3.03 bar

I take it that's with the vaccuum off and plugged? good guess at 3 bar by me then lol, I think any car I've ever noted it on was 3 bar base. Ross

Can I use a Tyre pressure gauge? I'll throw it away at the end of course, LOL