s5 TII fuel pressure question

NoDOHC · 06-18-2011, 10:05 PM

The FPR regulates fuel pressure by dumping fuel to the return line. If the pump is flowing more fuel than the FPR can handle, it will not be able to regulate pressure. The fuel pressure falling when under boost is an indication that this is the issue, as the injectors are using some of the fuel from the fuel pump, allowing the FPR to dump enough.

I would look into replacing the FPR with either a bigger aftermarket one or a newer (FD) stock one. I have not had this problem, but I have never required a bigger fuel pump than stock either.

06-18-2011, 10:05 PM	#14
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	The FPR regulates fuel pressure by dumping fuel to the return line. If the pump is flowing more fuel than the FPR can handle, it will not be able to regulate pressure. The fuel pressure falling when under boost is an indication that this is the issue, as the injectors are using some of the fuel from the fuel pump, allowing the FPR to dump enough. I would look into replacing the FPR with either a bigger aftermarket one or a newer (FD) stock one. I have not had this problem, but I have never required a bigger fuel pump than stock either. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)