Hi plumber,
before installed the higher fuel demand heffner tt bolt on system(800 rwhp), never got a low fuel rail pressure error. Never seen any error with subsequent upgrade to UR stage 3 TT as runs separate motec controlled fuel delivery system for TT fuel injectors.
From my experience running a heffner stage 1tt on my 2011 lp560-4, I found from vcds logging that my oem hpfp was not providing 120 bar through the full rev range in 5th gear while carrying out 1000metre sprints. Engine went into limp mode and then 'max 6000 rpm' message on display. See attached.
Ran vcds scan and got the dreaded error code P0078- low fuel rail pressure.
Also did run with online vcds logging and showed that delivered rail fuel pressure was not meetinfg requested 119 bar- see printout.
Problem solved by purchasing from Loba sports upgraded HPFP's and installing. See attached to get in touch with them. Same upgraded HPFP for AUDi RS6 v10 TT.
www.loba-motorsport.com
Problem solved! 120 bar all through rev range in every gear to rev limiter in 6th and no more P0078 error.
trust above of use.
cheers,
john