Running rich at atmosphere
 

Ok so I have a begi fuel pressure reg that boost fuel pressure as boost increases and that part is fine.
I have bipes for timing doing fine..

Where I am not doing fine is at no boost no vac and say 5 vac. it is riching up to 10.5 or richer. So i adjusted the BEGi fuel onset so there is no additional fuel pressure added by it at no boost/atmosphere.
So I rev the engine with the begi disconected and still the fuel pressure jumps to 48-50. So I remove the vac hose from stock fuel pressure and pressure jumps to 48-50. How do I prevent this. it is the only place this thing is not tuned at. Its fine at full boost, at light throttle at mid boost

BUT at slight vac to .5 psi I am RICH.

Is the stock fuel pressure reg supposed to do that. Can I stop it. It needs vac to keep pressure at normal 40?


Thanks in advance

MS. Works good.

Yeah I know. I will as soon as I can afford it.
I put a one way vacum check valve in line and it improved to 11 still to rich but better.

Are you vta or recirc? What type of injectors?

stock ECU with Walbro 255 = rich out of boost.

you want around 45-50psi with the vac line pulled off reg. try scaling it back a touch and see how it reacts.

thanks I have it at 40 at atmosphere on the begi fmu same as stock with vac.

So there should be no additional pressure till it see's boost. Turns out the stock reg was adding a little at atmosphere up to 45. I put a one way valve in and it helped a little. I am trying to adjust my o2 clamp to get it a little leaner at atmosphere.

thanks