Can someone just help me understand returnless fuel systems. I have a 307 2.0 in that when starting from cold will die when throttle opened wide, pops and back fires into manifold.
Which to me sounds like a fuel supply problem. I've got 50 psi fuel pressure and if I disconnect the fuel feed from the rail and test with coda, I can crimp the outlet pipe to maintain 50 psi of pressure while it's cranking, but there is barely no flow, which would indicate a problem to me.
Would this be an accurate way of testing?

TIA

Chris