Originally Posted by vicious_fishes
i'd say it's your fuel pressure reg/ecu/fuel relay rather than the pump. the pump itself doesn't control how long it remains on for.
tried a different pump to make sure it's not faulty? process of elimination...
The pump is tested and working 100%. I'm 90% sure the ECU isn't the cause as the tuner was confused as to why we are slightly under base pressure as a result tuned 90% IDC @ only 21PSI .
Whats the best way to test the relay and is there a way that i can test the FPR's while its on the car? Im running twin OEM FPR per rail setup, (at the end of each billet rail sits a OEM FPR.)
I also disconnected the relay so that there is no pressure and reconnected it to see if it builds up properly but still reads 4 PSI under base.
Originally Posted by ride5000
what does the fuel rail pressure read with the FPR manifold reference disconnected?
Do you mean disconnect the manifold reference vac lines to each FPR (as im running the twin setup) and read what pressure it's getting?