alright, some of you may recognize me from SHO. heres the background(cracks knuckles):

my 90 crx si is running off of a chipped P28, tuned for my setup: (ill just copy my sig from sho)
D16Z6, arp rod bolts, OBD1 conversion/chipped P28, Comp cam, intake, JRSC@5 psi, Walbro 255lph fuel pump, 2.5' catless exhaust, tuned via CROME Pro, 6 puck, 8lb fidanza flywheel, b&m shortshifter.
for fuel pressure, the tuner said i could leave the FMU in place and oem injectors. a/f is 12.0 across the board.
more history: i had a header, and last week, i put it on. its seriously a bitch to put a header on a z6 swapped rex. anyways, the threads on my 3-4 month old bosch oxygen sensor looked chewed up, so i decided not to risk threading it in and screwing up the bunghole threads lol. so, i plugged it up, but tied it off out of the way, and plugged my bunghole for the o2 sensor. so when i cranked it up, no CEL. runs like usual.

now to the dilemma:
after install/cleanup, i take it out for some friendly runs against a friends 04 rsx-s k20z. after racing, check engine light comes on. next day or 2, i park facing down a hill in my driveway and my dad runs in and wakes me up and says gas is leaking(from near the tank). this was 12 or so hours after i had parked it. so i park it on level ground since, and no more leaks. never happens when facing up hill either. and next day, CEL comes back up and this time i pull into garage and pull the code 43(four long, 3 short)=fuel system supply defective or malfunction. and it never comes on from startup, its always like 30 minutes after ive been driving. since the o2 sensor has been left out, it will surge at idle and let off, back and forth sometimes. i called my tuner and asked him if there could be any faults with the walbro install and he said no there really isnt a wrong way to install it.

now since my sensor is still plugged in, the ecu will still heat it and attempt to take readings? is that right? because it wont be reading any HC,NOx, etc, it will read only co2 and o2 from the engine bay air. this could lead the ecu believe that my car isnt getting enough fuel? i dont understand, because the ecu is supposed to be running without the sensor..

my tuner said sometimes with the FMU the ecu will 'wig out' from seeing all the extra fuel pressure. but this never happened before the header, before the unplugged o2 sensor, or before the gas leak. so that i have determined, is not the issue.


thanks for reading my novel, and any feedback!