Late 2003 Fuel Problem
Thread Starter
Cruising
Joined: Dec 2004
Posts: 11
Likes: 0
Late 2003 Fuel Problem
Friends,
I have a technical question that no one has been able to answer so far, here is the situation: I own a beautiful 2003 Vette with a Procharger at 7lbs boost, LS6 Stage II heads, 42lbs. injectors, 224/227 cam, and a lot of other adds, at around 4500 RPMs or so, the car runs out of fuel, the stock fuel pump, even with a voltage booster is only putting out 20lbs of pressure at the rails, and I cannot for the life of me find a high output pump that would go in my car, (Chevrolet changed the design of the fuel pump totally for the 2003 Corvettes built after Dec. 03, which mine was) I even thought about retrofitting it with a 2002 Corvette fuel system, but that would be a huge expense, since I would have to change fuel tanks, sending units, ect. and one I would like to avoid if I can. If anyone has an idea, any suggestions or knows of a pump I may be able to use please let me know.
Thanks.
GT30
I have a technical question that no one has been able to answer so far, here is the situation: I own a beautiful 2003 Vette with a Procharger at 7lbs boost, LS6 Stage II heads, 42lbs. injectors, 224/227 cam, and a lot of other adds, at around 4500 RPMs or so, the car runs out of fuel, the stock fuel pump, even with a voltage booster is only putting out 20lbs of pressure at the rails, and I cannot for the life of me find a high output pump that would go in my car, (Chevrolet changed the design of the fuel pump totally for the 2003 Corvettes built after Dec. 03, which mine was) I even thought about retrofitting it with a 2002 Corvette fuel system, but that would be a huge expense, since I would have to change fuel tanks, sending units, ect. and one I would like to avoid if I can. If anyone has an idea, any suggestions or knows of a pump I may be able to use please let me know.
Thanks.
GT30
Drifting
Joined: Oct 2003
Posts: 1,540
Likes: 0
From: bloomfield nj
your car runs the ffs fuel system.it's a returnless on demand system.the fuel pressure regulator and fuel filter is inside the left tank.there are 2 fuel pressure regultors inside[1 in the left tank,1 in the right].the 1 in the right tank is basically to keep the right tank suction jet from losing it's prime.
anyway 20 lbs of fuel pressure is way too low.what is your fuel pressure at idle.normal should be around 55-60 psi[that's for a aspirated car].with key off,the system should hold at 50 psi.if you are running anything lower at idle,look at the fuel pump.also you can have good fuel pressure but low volume[this will also cause your problem].
the way the fuel is transfered from tank to tank in the ffs system is also different then the non ffs system.there is a suction pump in the left tank,the fuel pump pumps fuel to this.this pump keeps the bucket the fuel pump is attached to filled with fuel all the time.the main fuel pressure regulator is attached to the fuel pump.the check valve,primary fuel pressure regulator and secondary regulator control residual fuel pressure.inside the right tank is the secondary regulator and another suction jet.the secondary regulator in the right tank keeps fuel flowing to the right side suction pump and keeps the system from bleedng off.the suction jet controls the siphoning of the right fuel tank into the left.
hope this helps.
anyway 20 lbs of fuel pressure is way too low.what is your fuel pressure at idle.normal should be around 55-60 psi[that's for a aspirated car].with key off,the system should hold at 50 psi.if you are running anything lower at idle,look at the fuel pump.also you can have good fuel pressure but low volume[this will also cause your problem].
the way the fuel is transfered from tank to tank in the ffs system is also different then the non ffs system.there is a suction pump in the left tank,the fuel pump pumps fuel to this.this pump keeps the bucket the fuel pump is attached to filled with fuel all the time.the main fuel pressure regulator is attached to the fuel pump.the check valve,primary fuel pressure regulator and secondary regulator control residual fuel pressure.inside the right tank is the secondary regulator and another suction jet.the secondary regulator in the right tank keeps fuel flowing to the right side suction pump and keeps the system from bleedng off.the suction jet controls the siphoning of the right fuel tank into the left.
hope this helps.
Drifting
Joined: Oct 2002
Posts: 1,710
Likes: 0
From: Langhorne PA
GT
I've got the FFS fuel system with an I/C Mag S/C. There was no upgraded fuel pump with the FFS system at the time so went with the KB BAP running at 100% when it kicks in (Got rid of that rheostat and soldered the wires together). My FP is 59psi through 6K when the shift light starts flashing (or that's when I notice it). Seems like your voltage booster isn't boosting. I would start looking there. Good hunting.
I've got the FFS fuel system with an I/C Mag S/C. There was no upgraded fuel pump with the FFS system at the time so went with the KB BAP running at 100% when it kicks in (Got rid of that rheostat and soldered the wires together). My FP is 59psi through 6K when the shift light starts flashing (or that's when I notice it). Seems like your voltage booster isn't boosting. I would start looking there. Good hunting.
