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Old 12-09-2012, 03:59 PM   #1
Scooby Newbie
Member#: 322645
Join Date: Jun 2012
2012 WRX

Default Fueling issues with 2012 WRX on E85


I have a 2012 WRX that I have some fueling issues with. Car is on E85. Mods are as follows.

- Kinugawa td05 20g
- Walbro 255
- FIC 900cc injectors
- Catless DP
- knock-off tmic
- TP street tune

One day the car started showing 10% to 25% fuel trims on cruise. Current map has been on the car for almost 10k miles. Took it to a local shop and they checked fuel pressure and did a smoke test. Found out I was losing the drivers side endtank on my IC. I needed a replacement and bought an E-bay special due to Christmas coming up. Yes I know the horror stories but I could not drop $800 on a brand name one a month before Christmas. Install went smooth but when I reset ECU the issues came back. Here is what I am seeing from logging.

- very positive fuel trims at cruise that sometimes swing back negative
- popping p2097 code post cat too rich
- WOT A/F is pig rich. I have no idea how rich because its pegging the stock O2 at 11.02.
- above 5800 rpms the A/F swings lean, very lean. Thank god for E85. No knock.
- Getting misfire codes on start-up sometimes. The a/f is pegged as rich as it can go and you can smell the ethanol. It feels like so much fuel is being pushed its preventing proper combustion. No suprise on a 20 degree day here it started fine on one crank. Normal day or hot cranking it just feels like its flooding the engine.
- I believe from the fuel pressure test that I was looking at 35psi idle and 57psi with the vacuum line to the FPR unplugged.

So my question is what are the likely culprits? Does this ring a bell for any of you. I really don't understand the fuel trims going lean at cruise then pig rich under boost before going scary lean. Car drives like normal minus start ups. Idles fine. Similar Maf g/s as before. No knock. Any advice would be greatly appreciated. Thank you.

Log below is from WOT pull.

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