| well I learned as soon as I drove the car that I am still having issues. While the car was idling and warming up the fuel pressure was ~36psi. Once I started driving it I noticed right away my afr's were way too high (cruising around 16). Upon stopping my idle is down at ~32psi (If I pull off vacuum it goes to 42psi). This doesn't seem like enough pressure drop off to have my afrs so lean though. The lowered fuel pressure would make sense if my car pulled too strong a vacuum but it is normal at -19. I did one brief WOT on low boost to see what happened and my afr did go down to 12 which is lean but shows that there is apparently some fuel pressure. Until I hit boost it was lean and I heard some definite pinging in the crossover area but not in boost; I don't intend to do that again. What I did:
-Cleaned tank of all sediment and rust after draining.
-Cleaned fuel sock with carb cleaner (didn't seem too bad though).
-Replaced fuel filter, old one was nasty.
-Blew out old fuel from all lines with air. What I can do:
-Replace fuel pump (seems to be giving fuel, if I clamp return line pressure goes up to about 60psi).
-Check FPC??
-Change FPR again (seems unlikely with <3k miles)
-Tune it richer via Nistune...bandaid? I've already tuned it to what should be very rich. I previously had perfect cruise afr with a much lower k-value.
-Change out DW injectors (never caused lean running outside of idle which was fixed via tune). This is a last resort due to cost.
-Pull and re-calibrate wb sensor...seems unlikely
-Mount fuel pressure gauge in car to see pressure at cruise and other speeds. I could keep typing things but I think this gets the general idea across. I wouldn't think the tank would already be causing rust issues again 24 hours after a thorough cleaning. I'm not sure what to do next and I don't want to just start buying parts and crossing my fingers. PS: I tightened the lines on the short hose in the tank and now my fuel pressure only bleeds down to 20psi instead of 0 when the car is off. Small victories... Thanks!
'91 TT |
