Fuel pressure drop after top feed fuel rail + big injectors

[tacoboy]

Hey guys, Im fucking stumped.

Put in 660 CC top feed injectors, and an OBX top feed rail. For the life of me, I cannot figure out what my issue is. For troubleshooting sake, I have a walbro 255, have bridged the gap where the fuel filter is (to elimate that as a cause).

My AEM fuel pressure regulator has been grate to me. 1:1 rise in fuel pressure with the stock rail and stock 370's. Now, when i watch the gauge, it drops from 45 psi to 15-20 when I crack the throttle. Pinching the return line yields the same result.

Is my pump not moving enough fuel to the rail?
Is the FPR fucked?

Does make sense to me, as there is tonnes of presure (55 psi if i turn it up), but the pressure drops so rapidly when I rev it up. I have also tried claming the FPR return line to see if it pressure drops, and it does. SO I beleive the problem is between the fpr and the rail - possibly the pump (but that doesnt make much sense)

HALP!

Dave

[steve shadows]

OBX is CRAP

TOP FEED INJ on SR's (unless they are 1000 CC MSD) ARE CRAP

AEM FPR is CRAP imo

this could all be helping add to your issue.

Always use SARD or Aeromotive only for FPR

Always use SARD or STOCK for Fuel Rails

Always use Side Feed High Impedence Denso/Nismo/Tomei Injectors only if they are available in the size you need. Your like will be ten times easier later on.

I suggest it's just coincidence and that your Fuel Pump is failing now that there is more demand for volume out of your fuel system. I hope you upgraded your fuel pump! anyways if it's walbro, these are CRAP and usually die or start to drp off in pressure as they get older. I would suggest gettinga denso 295lt / hr high quality in tank pump

[waynehead05]

^ wow. That's very to the point lol