Losing fuel pressure during hard acceleration??

[regal454]

I recently finished my engine swap and took it out the dragstrip for a few full throttle ecu learn passes last night. After checking the data log when I got home, I noticed I am losing fuel pressure under heavy acceleration. The pressure drops to 12psi and the the afr rose to around 18:1. At idle and light loads, it maintains a steady 58 psi. Here are the specs on my set up:

Car:
1969 Camaro
LY6 6.0
T56
223/230 .601 lift cam
LS3 intake
Holley HP EFI
Walbro 255lph fuel pump
Tanks Inc pick up module
-6 fuel lines
Corvette regulator/filter mounted by fuel tank

I contacted Tanks Inc and the tech guy there seems to think the regulator is mounted too far from the engine. I have never heard of this being a problem before? The voltage stayed at a constant 13.4V throughout the run.

I've attached a copy of the data log to this thread.

Any help/thoughts/insight on what may be causing this would be greatly appreciated.74286

[68Formula]

Moving it up might help a little, but not that much. Sounds to me like either your pump isn't keeping up, or there's a restriction prevent fuel to getting to the pump. Or your filter is clogged.

Move the regulator between the engine and the pump. Then put an inline gauge right at the pump. Measure voltage right at the pump as well.

Once you figure it out, I'd add a separate (non-regulator) filter before the pump.

[regal454]

Move the regulator between the engine and the pump. Then put an inline gauge right at the pump. Measure voltage right at the pump as well.

Once you figure it out, I'd add a separate (non-regulator) filter before the pump.

I think I will try a new filter/regulator-even though everything is new (tank/pump/filter/lines).

The pump is brand new-Walbro 255lph which should be more than enough for my combination?

[cornfedbill]

I agree, moving the regulator would make little difference. I really doubt this is the issue.

Check the pickup in the tank to make sure it is clear and submerged in the fuel completely. If it is in a sump or can, make sure the return fuel dumps right into the sump or can right by the pick-up.

Also make sure your pump is getting enough voltage like 68formula said. It will not deliver full capacity if the voltage dips. There is a remote chance that the pump is defective, but unlikely.

[regal454]

Check the pickup in the tank to make sure it is clear and submerged in the fuel completely. If it is in a sump or can, make sure the return fuel dumps right into the sump or can right by the pick-up.

Also make sure your pump is getting enough voltage like 68formula said. It will not deliver full capacity if the voltage dips. There is a remote chance that the pump is defective, but unlikely.

I am running the Tanks Inc fuel pump module. It returns the fuel into the sump. I wil check the voltage under acceleration.

Thanks for the input.