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I am trying to tune a 2003 Cobra with a return fuel system. I have done a read on another cobra previously tuned for a return without frps and did a compare but I didn't see any "switches for fuel pump type" or what seemed like enough changes. Looking for a tutorial or the correct process. Any help would be appreciated.
here is what is required if you were using SCT software, HP is just now supporting 04 and below with the Latest Updates, where SCT has been supporting for years. i have not looked at HP setup for the older cars always use SCT..
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.
If Eliminating all Returnless Components:
Go into System Switches / Scalar: Set Fuel Pump Type and Fuel Pump System Type to 0 if present.
Set All Fuel Injector Slope Multipliers & Breakpoint to 1.
In Addition to those changes these steps are recommended
f keeping the FRPS:
(Always suggested!)
1: Set all 3 of the returnless PIDs to 0.
2: Set the FPVT (fuel pump voltage table) to all 15s.
3: Set "Desired Pressure Drop Across Injectors" from -3 to -5 psi below base regulator pressure (with vacuum line off). This is to account for "droop" in the mechanical regulator, and to prevent a safety test within the calibration from activating (see more below).*
4: Set DTCs P1233 and P1237 to 0.
*On a return-style system, due to "droop", pressure can drop 3 to 5 or more psi at WOT. This is completely normal, as all mechanical fuel pressure regulators have this droop. With that being said, there is a test in the Ford ERFS (electronic returnless fuel system) calibration called "Fuelpump Tst Tm Below Desired Fuel Pressure for Error" (this is normally set to 8 seconds from the factory), which states that if FP drops below whatever the parameter "Desired Pressure Drop Across Injectors" is set to, for more than the value of the aforementioned test, then fueling will revert from the "Base Fuel Table" to the "Commanded Lambda when Cyl Off" table. It's important you lower your "Desired Pressure Drop Across Injectors" to match this droop (there's other methods besides from this, but this is the simpliest), and possibly even lower it further, otherwise you may find yourself having near total fuel cut at WOT.
Thanks mustang_man for that info!