Fuel pressure issue

mike miller

Registered
I've installed a stedman/rcc kit on my gen one 07, I'm in the process of setting base fuel pressure
I'm using walbro 255 ext and begi fmu. Even with the fmu center adjustment full out the lowest fp i get is 53 at idle. Im thinking the begi can't relieve fp fast enough with the high flow 255 pump. I've seen this happen before when nothing else but the pump was changed to 255. Anyone got any idea to lower that a bit. If not I'm going to use woolich and just take fuel away from the iap map to lean out the idle a bit
 
I've installed a stedman/rcc kit on my gen one 07, I'm in the process of setting base fuel pressure
I'm using walbro 255 ext and begi fmu. Even with the fmu center adjustment full out the lowest fp i get is 53 at idle. Im thinking the begi can't relieve fp fast enough with the high flow 255 pump. I've seen this happen before when nothing else but the pump was changed to 255. Anyone got any idea to lower that a bit. If not I'm going to use woolich and just take fuel away from the iap map to lean out the idle a bit
It’s likely the shims in the fmu are bent keeping the fuel pressure elevated. It’s common for that to happen on the old begis if they were ran over 8psi for any amount of time.

Less likely, but still a possibility could be how your fuel system is routed.

it should go:
Out of the tank sump in to the fuel pump.

out of fuel pump to one side of the fuel rail.

out the other side of the rail to the fmu

out of the fmu in to what was the stock fuel feed originally.

Any deviation from that will cause fuel pressure problems if not just at idle, but wide open when trying to set the boosted fuel pressure.
 
It’s likely the shims in the fmu are bent keeping the fuel pressure elevated. It’s common for that to happen on the old begis if they were ran over 8psi for any amount of time.

Less likely, but still a possibility could be how your fuel system is routed.

it should go:
Out of the tank sump in to the fuel pump.

out of fuel pump to one side of the fuel rail.

out the other side of the rail to the fmu

out of the fmu in to what was the stock fuel feed originally.

Any deviation from that will cause fuel pressure problems if not just at idle, but wide open when trying to set the boosted fuel pressure.
I guess I'll open the begi and check the shim. My rail only has one t on it for the pump and fmu. The pump outlet is teed into the fmu before it meets the rail then they both run into the right side of the rail
 
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