Adrenaline718

Over the holidays, I made the following upgrades to my Evo:
- Buschur TBE Exhaust with Hi-Flow Cat
- Walbro 255 lph Fuel Pump
- Buschur Cone Filter Air Intake
- Dynoflash ECU reflash

The car sounds and drives amazing, but once when I was pushing it a bit accelerating, I got a check engine light, and the code is:

P0171 "System too Lean (Bank 1)"

Can anyone think of what might cause such an error? With the higher flow fuel pump installed, I would think I would see it running rich more than lean. Could it be that the tune didn't incorporate the higher volume of air coming with the cone filter intake? Or is there likely a more serious problem - like a boost leak or something?

Any advice or suggestions would be most appreciated. I've only owned the Evo for three months so far and it has just under 29,000 miles on it.

kaonashi

iTrader: (34)

Take your Maf sensor out and clean it, see if it changes any thing, normally you can get this problem if your air filter use's anytype of substance on the filter itall gunk up the maf and cause an incorrect reading. Use Maf cleaner from an autoparts store.

IF not i would get it fixed, your probably det in cyl1 if its a air/fuel issue and not the maf messing up.

Adrenaline718

The MAF sensor is brand new. I just had it replaced under warranty because the last one started malfunctioning a few weeks before I put in all of these upgrades. I could check it, but I doubt it is the MAF sensor. I was extremely careful with it when I put the air intake on.

Mad_SB

iTrader: (8)

Could be several things. The filter, the tune, a bad injector, bad o2 sensor..... If you have a dyno in your area, go pay for a pull and get a log of the airfuel and boost. Or buy a tactrix cable and download mitsulogger and log it.

In general, if you get a system too lean or a system too rich it means the fuel trims are maxed out at + or - 25% and the narrow band 02 is still not happy.

Also, I think someone else posted this same issue recently after a dynoflash tune, but that was on a meth map I think.

Adrenaline718

Thank you. I actually called a shop this morning and asked for their price on a tune in hopes that will clear it up.

BBS

iTrader: (18)

Do not go in asking for a tune-up. Go in asking that you want the problem resolved. If you go into a shop asking for a tune-up, that's all youre going to get (they might even replace parts that you dont need to replace.)

churchja

iTrader: (17)

This happened to me a few weeks ago... Did all the checks mentioned above... 1) checked the MAF sensor, spark plugs, cleaned the air filter... I doubt it is your injectors because you'd probably be getting some PO300 (misfire codes) as well at the 171. Might be a bad O2 sensor, but I doubt it since yours is an 06. Might want to have the shop at least check the sensor; could just be dirty.

Here is what I found and fixed my 171 issues. One of the bolts on the bottom side my O2 housing fell out and was causing the lean condition (171 code) . Might want to check all your exhaust connections; especially if you have an aftermarket O2 housing. Also with my issue, the Evo sounded "loppy" almost like it had aftermarket cams sound. I could hear the "leak"; but didn't know what I was listen to. Also, I would only get the 171 code at idle/near idle conditions. Once I fixed the leak by intalling new bolts and replaced the gasket on the O2 housing; no more 171 codes or any other CELs since.

Anyway, just something else to check... Please follow up and let us know the cause once resolved.