4 Bar Pressure

[gncgray]

Been having fueling probs latley. I have fitted a fuel pressure gauge to see whats happening and I'm getting about 4 bar pressure as the fuel goes into the fuel rail. Is that the right figure I should be getting?

 

 

I am using a Sytec H/P pump with a Zetec and standered rail/injectors.

 

 

Ta

Graham

[Grim]

seems on the high side to me. If the pressure is too high it can prevent the injectors opening / spraying properly. Normal is 2.5 to 3bar i believe.

[brumster]

The short answer is, it depends on the map. I run 4 bar on another car that has been mapped to that pressure - but whether it's standard for a zetec (and whatever management you're running), I honestly don't know. Certainly 4 bar isn't a problem, per se. Is the regulator standard - I'm not au fait with Zetecs; is it part of the rail?

 

edit: ^^ beat me to it; if the standard pressure is 2.5 or 3bar, then you're fuelling will be off (on the rich side) assuming the ECU map is for the lower pressure.

[Longboarder]

Most aftermarket systems, emerald, omex, megasquirt would be set to run at 3bar as a starting point. The map would be written for 3bar. Having said that if you are on a rolling road and found the fuel pressure not quite 3bar but say 2.7 bar and the regulator is not adjustable then there's nothing to stop you writing a map for 2.7bar. Or if the injectors were very slightly running out of capacity at full chat then you could up the fuel pressure to 3.5bar and map at that pressure.

Usually a map when written will have a note saying what engine, mods, fuel pressure what injector flow.

So if your fuel pressure has always been 4bar then the problem is not that.

Nigel

[gncgray]

Thanks guys...very helpful