kompressorgolf

done a ton of searching only to find 1 thread on all the sites about people having trouble with too high of fuel pressure, and it was a b6 returnless system.

Heres the back story. car started hard starting warm or cold, but seemed to start fine after warm and you restarted after only a few minutes. long story short after replacing wear items such as plugs with ngk bkr7e gapped at .24, fuel filter, engine speed sensor, coolant temp sensor. then i find the factory fuel pressure regulator blew out, fuel in the vac line. i figured its what took out my oem pump as well causing it to overwork. instead of replacing it with an oem i mounted a walbro 255 for future stage 3 aspirations. i replaced the FPR with one from an allroad same 4 bar but it was used. and then all was well, then i had a maf code, so i sourced an MTM stage one mbox ecu and converted the car to hitachi maf 2000 S4 manual BTW. All was fine. a week later im having hard start problems and notice the car has misfires only at idle, mainly cyl 4. I did the whole swap coils and plugs, change out my ICMs with known good backups, even swapped out a spare injector, still cyl4 mis, only at idle, runs awesome up top, 15 psi. So i decided to purchase a fuel pressure test kit, and ran the car, and this bitch is running 85 to 90 psi, so this time i bought a new bosch 4 bar fpr and popped it in, restarts great again but still had this misfire, checked fuel pressure again, still 85 90 psi at idle, even the bad fpr with fuel puking from the vac line was still pushing 80 psi. ive pulled the rail out and made sure nothing was plugged, blown through the fuel return line to the tank, ran a line from the return port on the rail to a bucket, all with no change. the only way i can get the fuel to a proper 58 psi at idle is by pinching the feed line almost closed. completely bewildered! Cant find anything about too much pressure! I run a walbro on my 400hp turbo vw rabbit, with the early style 3.5 bar digigant style fpr and its regulated perfect for years. please anyone have any insight or ideas>>???? Thanks in advance!