FPR Questions??

[000triple000]

I am running a walbro 255 with a aftermarket fuel press. reg with a gauge on it. i got my car running with it on there and it stays at like 25psi, and when i give it some revs it goes up to 27 or 28, then goes back down to 25, when i remove the vacumn line it doesn't move, so I adjust the know and try it all over again and nothing, i adjusted the nob up and down and did the repeated steps and nothing, What im curious about is why its not going up, and im going to install dsmlink chip into the ecu but im afraid this will cause a problem. im getting ym wideband hooked up tom. after i figure out how to wire it in, but the tune that came on the dsmlink chip is for 2g maf and 450 injectors, so i don't want to install that and jsut start it, don't want it to blow up. and questions or need mroe info message me, Thanks for looking and any possible explinations. Oh and my fpr is brand new.

 

[TalonTsi_291]

What regulator is it?

 

[rlacasse1]

Correct me if I am wrong, but, the pressure shouldn't change if the vacuum line is off of it.

The fuel pressure should always be the base pressure plus the manifold pressure. So if you have 25 for pressure as a base at 10 pounds of boost you should have 35 for fuel pressure. And vice-versa, if you are in vacuum then the fuel pressure will drop.

So, it makes sense that it is not changing with the vacuum line off.

Anyways this is to my understanding.

And if this is not what you're asking then sorry, but your post confused me a little.

 

[TalonTsi_291]

Your supposed to set base pressure with the vacuum line removed. It needs to be set at 43 psi.

 

[Mopar McNeer]

The pressure on the gauge will change when you remove the vac line,

As mentioned above, you need to set the static (base) fuel pressure by removing the vac line and making the adjustments to get it to you desired pressure (ie: 43), tighten the adjustment lock nut and reinstall the vac line. With the vac line connected, you should see the fuel pressure drop. It will hit the base pressure at 0 vac/0 boost. If you have a rising rate FRP, you will see it add 1 lb of fuel pressure for each psi of boost.

 

[000triple000]

Alright I will try this tomorrow, It just got built and it doesn't like to be started, And for some reason its running rich, the place that built it had the adjustor screw adjustade to 2000rpms idle i was like wtf, but i think the screw under the maf needs turned down a little bit.

 

[TalonTsi_291]

What fuel pressure regulator are you using. If its ebay, and doesn't do anything when you try adjusting it. Its probably garbage.