High fuel pressure that goes up and down
12-19-2006, 10:33 AM
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High fuel pressure that goes up and down I have a 1998 ls1 motor that reads 100 psi at the fuel rail when I turn on the pump. I have replaced the fact fuel pump with a MSD High Pressure Electric Fuel pump. The new pump is installed inline, not in the tank.
When the car is started, the pressure at the fuel rail reads 100 psi and stays there for about 30 seconds and then drops down and back up. It continues to flux between 100 psi and lower psi readings until the engine stalls.
I have replaced the fuel pressure reg and the fuel pressure pluse valve on the fuel rail.
I have installed a MSD high pressure electric fuel pump #2225. It's specs are, 43 gph @ 40 psi.
When I installed the new pump, I put a tee line just forward of the high pressure line from the pump to the motor with a line back to the tank with the fuel pressure reg installed inline. Any suggestion? Thanks, Boyd
When the car is started, the pressure at the fuel rail reads 100 psi and stays there for about 30 seconds and then drops down and back up. It continues to flux between 100 psi and lower psi readings until the engine stalls.
I have replaced the fuel pressure reg and the fuel pressure pluse valve on the fuel rail.
I have installed a MSD high pressure electric fuel pump #2225. It's specs are, 43 gph @ 40 psi.
When I installed the new pump, I put a tee line just forward of the high pressure line from the pump to the motor with a line back to the tank with the fuel pressure reg installed inline. Any suggestion? Thanks, Boyd
12-19-2006, 12:48 PM
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Reply to Thread I took the factory pump out of the fuel tank. The factory fuel pump has the fuel pressure reg attached to it near the fuel pickup filter.
Let me explain. The car is a 57 chevy with an LS1 eng and trans. I was running the factory pump in a fuel cell located in the trunk of the car and everything worked fine. I then took this out and replaced the fuel cell with a reg gas tank for the car. Put a regular sending unit in the tank for a 57 chevy and added a inline high pressure pump. Since the standard Ls1 fuel pump that went in the fuel cell had a high pressure regulator attached to it, I replaced it with a new factory fuel pressure regulator inline back to the new fuel tank.
Perhaps I need to relocate the new fuel pump back closer to the gas tank. Now it is mounted just under the driver side door. Here is a drawing of the configuration I installed
tee-----fuel Pressure Reg--------------------|
MOtor ---|----pump ------------------------------GAS Tank
Let me explain. The car is a 57 chevy with an LS1 eng and trans. I was running the factory pump in a fuel cell located in the trunk of the car and everything worked fine. I then took this out and replaced the fuel cell with a reg gas tank for the car. Put a regular sending unit in the tank for a 57 chevy and added a inline high pressure pump. Since the standard Ls1 fuel pump that went in the fuel cell had a high pressure regulator attached to it, I replaced it with a new factory fuel pressure regulator inline back to the new fuel tank.
Perhaps I need to relocate the new fuel pump back closer to the gas tank. Now it is mounted just under the driver side door. Here is a drawing of the configuration I installed
tee-----fuel Pressure Reg--------------------|
MOtor ---|----pump ------------------------------GAS Tank
Last edited by Sambuddy1; 12-19-2006 at 12:52 PM. Reason: corrected drawing
