If you used the right hose (Fuel line hose) a 4 inch piece should not effect the fuel pressure enough to kick the relay off. But when you first turn the key on,.. does the fuel pump turn on then then shut off or does it stay running longer then normal? Are you running an adjustable regulator or still the stock regulatory at the rail?

You need to realize the there should be between 30 - 40PSI of fuel pressure running through that line. I'm ok with 5 - 10PSI for a carb on hose clamps,.. but 30 - 40PSI over time will probably create a leak. This is just my theory and not proven. But perhaps someone with more experience with EFI fuel systems can chime in with the proper way to repair a EFI fuel line or if indeed hose clamps are ok.

Hurst