Low Pressure Fuel Help

[jomo]

Having a problem with consistent low pressure on the low pressure fuel side. Alldata says it should be 69psi - 75psi. But I’m only seeing 48-50psi. It’s pretty consistent, even at WOT.

Previous owner did bucketless Walbro upgrade. I checked it out and looks good. No kinks, and connections look good.

What should I change first?
-Low pressure fuel sensor
-Fuel pressure regulator
-EKP

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[KClemente]

Hm that's strange. N54's target 72.50 PSI at all (normal operation) times. You may have an internal fuel leak,

Try accessing the left side fuel tank hatch, it's common for our cars to have a crack right at the fuel outlet

 

[jomo]

@KClemente thanks for the feedback.
I checked the outside and didn’t see any cracks. I pushed around the area and I didn’t see any changes to fuel pressure on MHD.

I thought it might be related to the EKP module. I followed this guide here to modify the EKP values.

It didn’t change anything to the fuel pressure, but it did increase the LPFP PWM % from 0% to ~2%.

Any other ideas REALLY APPRECIATED!

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[jomo]

PROBLEM SOLVED:
It was the fuel pressure regulator.

Troubleshooting Steps:
-Coded EKP via NCS Expert (no change)
-Installed used OEM fuel pump (no change)
-Installed used OEM FPR (fixed)

The FPR that was in the car was not OEM. I also noticed it had an O-Ring stuck in the line.. so not sure if it was a failing non OEM fuel pressure regulator or the o-ring causing the low pressure.

Pic of the o-ring: