[Lou_austin]

Hey guys so I bought a 335i with a precision 64/66 and after getting some logs done with my tuner my fuel pump is only putting out 40psi. The car has upgraded fuel pumps and underneath the rear seat the wiring looks messy and I am trying to troubleshoot to make sure both pumps are working. Does someone have a wiring diagram I can use as a reference? It's running a JB4 with MHD backend flash and it's supposed to have dual walboro 450s and it has a helix 4x overdrive pump.