Washable air filter fuel trim issue

fabrizzio71

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Hi All,

I am posting an issue that can be caused from washing your air filter and not allowing it to dry fully/a PSA on how long it actually takes to dry (I have the 27 Won intake).

Over the weekend I changed my oil and cleaned my air filter for the first time. I followed the instructions on the cleaner solution, sprayed it, let it sit, rinsed several times until running clear. I shook it out, let it sit in the sun for several hours. Then I spent probably 15-20 minutes running a blow drier through it (used cool setting). Between blow drying sessions, I pressed a dry paper towel between the pleats and absorbed some water that way. I Let it sit a couple more hours and then installed back on the car. I started the engine once to check the new oil level but then the car sat overnight.

I had to go somewhere the next morning. I always drive with tunerview on the display. Fuel trims were almost immediately extremely positive 15-35 % STFT and it didn’t take long for LTFT to reach 15-18%. This was really nerve racking and I drove like a grandmother. I thought maybe my injectors went, but it was too much of a coincidence. Fuel trims decreased slightly later in the day but were still high that evening after work. Finally the next day, everything returned to normal. I didn’t think it would take 48 hrs to dry the air filter, that seems excessive. So I think I need to buy a second one and alternate them, bc I can’t afford to go that long without driving my car. I assume excessive water vapor in the air made the oxygen sensor think there was a lean condition and that is the cause of the extra fuel. Hopefully this did not create any long term issues.
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arpypat

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Yup, this happened to me the first time I cleaned my 27won filter and learned my lesson. MAF got wet, fuel trims out of whack, and idle bouncing like Bugs Bunny

1-2 hour dry time isn't going to cut... I let mine sit for 8-12+ hours now before I reinstall and start the car. Best to have a spare altogether.
 

gtman

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I always give the washable filters 24 hours just to be sure.
 

Vlad@27WON

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We'll add this advisory to the listing for our 27WON Air Filter.

Definitely need to let that bad boi dry well!
 
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fabrizzio71

fabrizzio71

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Yeah, except
Yup, this happened to me the first time I cleaned my 27won filter and learned my lesson. MAF got wet, fuel trims out of whack, and idle bouncing like Bugs Bunny

1-2 hour dry time isn't going to cut... I let mine sit for 8-12+ hours now before I reinstall and start the car. Best to have a spare altogether.
Yeah, I mean it was 18 hours before I drove it. The car didn’t run bad, and if I didn’t have tunerview on I may not have known any different, but fuel trims being that off can’t be great for the car. If it was a matter of the MAF getting damp, I could have taken it out and cleaned it but I didn’t even think of that. In any case lesson learned.
 


pdimar25

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I'm about to wash mine (mishimoto) and I usually let it sit in the sun for half a day.
 

xXoVrKiLLXx

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I bought a spare just so when cleaning one Im not in a rush to reinstall it and it can dry while I have the other one installed.
 

SDAlexander8

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Ive seen people put too much oil on the filters too which can cause issues. People complain these filters don’t capture very fine particles. I’ve seen nasty old ones that have almost no oil on them and they're all smashed up. Waiting 24 hours for a filter to dry is horrible unless you’ve got more than 1 car.

I don’t care about 3 extra horsepower or wooshy sounds. The ease of just replacing a normal air filter every 25k miles and knowing it will just work outweighs the stress related to my OCD when maintaining a high-flow filter.
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