Fuel pressure regulator 52psi base ??

JT's03

Registered User
The setup is single 255lph pump (2nd activated by boost switch although irrelevant for this discussion because it is not hooked up at the moment), 01 or 02 ford windstar fuel rail and regulator, -8 feed and return, yada yada... Wired directly to ccrm with a 30amp relay for key on (one on each pump) and the pump is 100% on when the key is on.

As the title states base pressure is reading 50-52psi at the rail confirmed by fuel rail pressure sensor and a marshall liquid filled mechanical gauge. Key on engine off 50-52psi, key on engine off pulling vacuum on the line manually I got it down to 42 psi. Engine running without vac 52 psi, engine running vac hooked up 46psi with -16 psig on the vac gauge for idle. Engine off key on applying pressure to the regulator via hand pump the pressure got up to 81psi so it pressure is rising with air pressure applied.

At first I thought the pump was overwhelming the regulator but now think otherwise because pressure goes down with vac hooked up. Wondering if I should keep this regulator in play and tune accordingly including base fuel tables or buy another regulator? Any insight would be greatly appreciated!!!
 
I have been running 46-47 psi at idle w/vacuum for a year or so, my 60# injectors were maxing out at 42 psi Idle. It runs fine but I had to redo all my fuel tables that was not to bad but I have a lm1 to see my AFR. Not sure what I have with out vacuum.
 
Running your base pressure that high isn't really a problem so long as you can adjust the tune, but it will reduce the amount of power the pump and injector combo can support, because the pump flow falls off sharply as pressure increases. If it were me, I'd install an adjustable regulator and lower base pressure to about 40 psi.

David
 
sounds like the regulator is performing flawlessly, why would you even consider replacing it?

as long as your max line pressure doesnt cause the injector to pressure lock then roll with it

usually most of the tunes I do below 60lb injectors I run 55psi base pressure, so long as boost doesnt exceed 20psi, (exceeds 75 psi line pressure) then I wouldnt even be in the slightest bit concerned
 
Running your base pressure that high isn't really a problem so long as you can adjust the tune, but it will reduce the amount of power the pump and injector combo can support, because the pump flow falls off sharply as pressure increases. If it were me, I'd install an adjustable regulator and lower base pressure to about 40 psi.

David

Did not know that. I will be running 2 of these pumps 2nd activated by boost switch. Attached is the flow sheet of the pump I'm running. I had good luck with the hfp gt pumps when I was running returnless I bought 2 of their 255's.

sounds like the regulator is performing flawlessly, why would you even consider replacing it?

as long as your max line pressure doesnt cause the injector to pressure lock then roll with it

usually most of the tunes I do below 60lb injectors I run 55psi base pressure, so long as boost doesnt exceed 20psi, (exceeds 75 psi line pressure) then I wouldnt even be in the slightest bit concerned

I was under the assumption I needed to see 42psi with an oem regulator. I'm swapping from a returnless system so it's fairly new to me. What would you set my base fuel pressure to be in the tune? It's 39.5 currently as I have not changed that yet. It varies from 47-52 base fuel pressure. I have the sct pro-racer.
 

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Here is what I changed in the tune...

"OPTION A"
If Retaining the Pressure Sensor Hardware, but using a Regulator to Control Fuel Pressure:
Go into Returnless Fuel Pump / Fuel Pump Voltage Table:
Set the entire table to 15’s.
Go into Returnless Fuel Pump / Desired Pressure Drop Across Injectors:
Set the Right Column to ~10psi above the Regulator Pressure you are running.
Go into Returnless Fuel Pump / Scalar:
Set Fuel Pump Gain Derivative Term, Fuel Pump Gain Integral Term, and Fuel Pump Gain Proportional Term all to 0.
Set Fuelpump Tst Pressure Below to Allow Test to ~20psi below the Regulator Pressure you are running.
Go into System Switches / Scalar:
Set Fuel Pump Type and Fuel Pump System Type to 0 if present.
 
Never had that problem but I'm running a a1000 with 8n feed line not sure how that compares to 2 255's.

Running your base pressure that high isn't really a problem so long as you can adjust the tune, but it will reduce the amount of power the pump and injector combo can support, because the pump flow falls off sharply as pressure increases. If it were me, I'd install an adjustable regulator and lower base pressure to about 40 psi.

David
 
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