With my Aeromotive regulator, it is not able to consistently maintain fuel pressure. I have it set for a base pressure of 48psi, which makes it idle at about 44psi and it will go down to 39psi on decel.

But the regulator can't seen to be able to maintain this. This morning for example, the fuel pressure was 39-40psi the entire time. Its only a few PSI difference but that makes a big difference if running open loop or in boost.

The nut on the adjusting screw is plenty tight. The regulator is plumbed into the return line.

Anyone else had a similar issue? I may try upping the base pressure back to 58psi. I went with 48psi since my injectors are overly large and appear to have an issue pumping in too much fuel on decel.

 

I had a problem years ago, and there was a piece of debris in the seat of the valve. Take the regulator apart and see if there is anything not letting it fully close. Are you checking the pressure at the regulator, or are you cheking it farther down the fuel system?

 

Good idea, I'll take it apart and check. I'm checking it at the rail with a pressure sensor and a mechanical gauge. Both show the same issue.

 

Took apart the regulator and didn't find anything out of the ordinary. I put it back together and raised the base pressure to 58psi thinking maybe it will have an easier time maintaining a higher pressure, who knows.

 

Looked through some of my logs today and noticed that the fuel pressure is not increasing with boost in a 1:1 ratio as they claim. With base pressure set to 58psi the fuel pressure only got up to about 60psi at 10psi of boost. It modulates pressure just fine in vacuum though.

Any thoughts on this one? I may give Aeromotive a call tomorrow.

Even the stock regulator would raise the fuel pressure at almost 1:1 in boost, and did so with a 255 pump and stock wiring. I have a Walbro 400 pump and hot wiring now so I don't think it's a pump issue.

 

How are you measuring it? I dont trust my aeromotive electric fuel pressure gauge for what its worth.

 

I have two gauges; a mechanical gauge from Turbosmart, and an Autometer electric sending unit that I wired into the EGR signal so I can log fuel pressure through the PCM. Both are located at the same spot on the rail and both read within a couple psi of eachother. I'm only reading the data from the electric sender to see what the fuel pressure is in boost since the mechanical gauge is on the rail itself.

 

Hmmm. Weird. My aeromotive fpr increases with boost no problem.

Does yours decrease with vacuum?

 

Yes, works very nicely in vacuum, gets down to 47-48psi on decel, 51-52psi at idle, 58psi with vac line disconnected.

 

Which model do you have?