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-   -   LTFT + STFT very negative Idling, Oil dilution with gas smell problem (https://www.ft86club.com/forums/showthread.php?t=146267)

FrickingReallySlow 07-26-2021 11:21 PM

LTFT + STFT very negative Idling, Oil dilution with gas smell problem
 
Hey guys, hoping some of you can help me pinpoint an oil dilution and LTFT problem on my 2015 FRS with 60K miles Edelbrock SC boosted with D-Box/delicious tune. Oil was changed in May and i've only gone 1K miles so far with mix city /HWY. I first checked oil level in June and saw that oil was above the top circle so I drain some and thought mechanic overfilled.

This week I check oil level again and saw the level was WAY above the top hole AND the oil smelled like gas:cry: so most likely my oil is getting diluted with gas. Did some logging at idle for 12mins.

https://i.imgur.com/TnZ5aBx.jpeg

Here's The log and some of the things I found interesting.

https://datazap.me/u/s0007/2015-frs-...24-25-30-33-34

STFT goes negative (-15%) immediately AFTER warm cycle, during this time injection PI ratio is 100% and fuel rail pressure is building from 610psi to 2370psi for ~6min. At ~6min mark PI ratio goes to 0% and LTFT takes over and goes negative (-17%) with STFT also at -2% for a total trim of -19%. Fuel rail pressure drops back to 580 psi and is stable. AFR seems to track and stable at stoic throughout.

I also did a PCV oil cap test with a piece of paper where oil cap is at IDLE and there's pressure from the crankcase (blowing at the paper) instead of slight vacuum sucking the paper onto the opening. What other problems could this indicate other than maybe a stuck PCV valve? I'm hoping its not my piston rings :(


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