03 2 valve Bank 2 fuel trim maxed out. Bank 1 running perfect. Help!!

[Jcarp1984]

I bought a 03 s281 five years ago. It's been sitting for the last 3 or 4 years. Get it back out to get it hyw worthy. At first I had tons of dtc codes. Finally got all them lined out and I watch the fuel trims on the hand held go to crap. I really don't even let it run long enough for the long terms to even load. Should I? I mean bank 2 is maxed out on fuel?. Redone the header gaskets, intake manifold gaskets. New 255 fuel pump new bank 2 injectors. New evap sensors. New fuel filter 3 times. I switched the new injectors over to bank 1 to see if it would move over and of course it doesn't. I've put in all new o2 sensors and checked them for current. New intake because the old ty one was getting air in it. It like it has a vacuum leak but I can't find one anywhere. I did notice my factory fuel rail crossover black flex pipe has a pinch in it. So I ordered a new fuel rail from lethal performance. I really hope this fixes it. I just put in a brand new pi intake manifold thinking, and hoping my old one was cracked or something. But nothing. Crazy thing is for the first minute or two the fuel trims are perfect with each other then bank 2 starts putting fuel into it. My driver side spark plugs are fouled pretty bad. Passenger side are just fine. Put new plugs same thing happens. If anyone has any idea what could be going on please help. At this rate I'm about to jump buy a megasquirt ecu and just bypass the whole mass air flow crap.

 

[7991LXnSHO]

Since no one has taken a chance on the answer, I will try, although this generation is not my main focus. These will be general EFI car thoughts.

So does the trim say it is running the injectors at full volume, or does that mean the sensors are saying it is rich on that side? Or is there a vac leak somewhere telling that bank is lean, and that sends the signal to put in more fuel? On an older generation Mustang, I know testing continuity of the wires between the computer plug and the sensors, then the same or a NOID light to test out the wiring to the injectors would be good diagnosic steps. A new computer system with the same harness might have the same problems, so you might as well eliminate that next. Can someone help with a wiring diagram for this car?

What kind of fuel pressure regulator does this have and where does it return the fuel from? Have you been able to test the fuel pressure?
If these are not the answer, I hope a bump will help get more attention.

 

[Deleted member 38176]

You most likely have a bad FRPS. My car sat a bit while getting built and when we went to start it up there were fuel issues. It turned out to be a ty FRPS. Swapped it with a new one and it ran like a top