Car Throwing P0171

icudruln

New member
So today is extremely freezing (high of 1 degree), and I figured I'd just let the STi warm up and cool back down. I just drove to the liquor store and back, and the car threw code P0171 Bank 1 System Too Lean. Previously, the car threw the same thing about two weeks ago, and nothing wrong was found (pulled the plugs, checked o2 sensors and cleaned the MAF). We couldn't get the car to duplicate it, so we cleaned the MAF and no issues until today.

Car has no issues getting up and going, or hesitation on take off.

Looking back, it was very cold when the car threw the code the first time, as it was in the teens. I rarely drive the car in the snow or cold, but the car is now relegated to daily driver duty for another week.

The car has never done this in any other conditions, so is it possible its related to cold weather, running on Ethanol (E85)? Should I be paranoid? I get my tax returns in a week and a half, and I'm getting all sketchy to the point where I'm seriously considering waiting on my suspension goodies I planned to order in case I end up needing a new shortblock. What do I do?
 

HolyCrapItsFast

Drinks beer!
Can you post a log driving in very cold weather. I feel that a compensation table somewhere in your tune is not ideal for very cold temperatures situations.
 

IGOTASTi

System Operator
Staff member
Holy could it be dumping to much fuel cause it's so cold out?
 

HolyCrapItsFast

Drinks beer!
I was thinking it was actually opposite and not supplying enough fuel at some point since he is getting a lean code. :)

I was thinking something like a temporary leaning out of fuel before the ECU had a chance to compensate like Tip-In enrichment or more specifically, coolant temp trims. Maybe his compensations are fine in normal weather but not when cold.

I duno... I'm just throwing stuff out there. I can't tell until I see a log and even then I can't guaranty it will tell us anything. :tup:
 

IGOTASTi

System Operator
Staff member
Yeah hard to say. I have seen cars throw a lean code, but dump so much fuel that it's rich then throw the lean code, cause the computer goes oops I made a mistake and then go lean. So your guess is as good as mind. I would be able to tell you if I hooked it up to my Snap-on Modis
 

IGOTASTi

System Operator
Staff member
Thanks! Just what I seen in other cars at the shop! SNAP-ON MODIS FTW!
 

HolyCrapItsFast

Drinks beer!
I just let the neurons do their thing. :tard:

Me to. I have this uncanny ability to see the numbers and values flowing through the ECU and in the engine. I can physically see with my mind how the air and fuel is flowing in the motor.

It freaks me out sometimes.

The down side for me is I am a social retard. I had to sacrifice something :tard:
 

IGOTASTi

System Operator
Staff member
Holy is like TRON!
 

HolyCrapItsFast

Drinks beer!
Ut oh... I think we're on the border of whoring up this thread :lol:
 

IGOTASTi

System Operator
Staff member
Well keep me informed Holy what you find out. I would like to know what you see.
 

icudruln

New member
Over scaling (dumping more fuel) would make sense...the car has been eating gas (e85) since the first code. Typically get around 180-220 to a full tank. Lately, I;ve been getting around 100 to every 3/4 tank.

^^^Not drunken talk :)
 
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