after my motor rebuild I have been experiencing really low o2's at wot(around 670 to low700's i think), an getting a whole lot of knock, on short punches I have built up as much as 24pnds with no knock and 02's of 830+, but on highway punches and at the track it's another story, just wondering what all could be wrong, my fuel pressure is set at 42.5, and have tried upping it, with no results, have a walbro 340, I know I need to check to see if my f/p goes up under boost, but don't have time to get out there and do it this week, we got the maf to flow 255 but was the same problems as 235, but just to get an idea of what all I have to look at, inj's to small? or is there to much to list, any and all thoughts would be very, very appreciated ,have ac delco 02, hotwire,all the normal stuff, mods below thanks
low o2's at wot
- Thread starter kmart17
- Start date
ok im leaning on your car is now making more power since your rebuild, as long as everything else is in line you might have to go bigger on the injector !we were running out of fuel with a set of msd 50# injectors at 11.20s i dont know how fast your car is though! you also might want to change your fuel filter if you havent tried that yet.
been out of town, with a real good tune, i am confident that it would be a mid 11's car, I did all the basic stuff witht the rebuild, fuel filter included, i dropped the tank to, to see if the pump was what I was told, it was a walboro 340, check fuel pressure at wot, it was 17psi over static at 15lbs of boost, the car won't knock if you hold 17lbs at part throttle, need to see what the o2's are with that scenario, starting to think false knock is the culprate, like overtorqued knock sensor, or tranny, we'll get it eventually, got bigger problems now, smoking hardcore on decceleration only, after a 130mph test session on hwy 20 in dallas, more details later 
