P0171 - Bank 1 to lean

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03.5 YLW MSP
I just went upto the local autozone to read my CEL and it came up P0171 - bank 1 to lean.


Now the list of possible issues are large vac leak, bad 02 sensor, dirty defective MAF, or engine mech condition...

The MAF and O2 sensor arn't even 2 weeks old literally. My vac at idle is 20/21... So I have no idea what would cause this issue unless its due to bad seals at the throttle body shaft(boost leak tested to find this one).
 
check your air filter hose to see if its cracked. i had the same problem with my protege.
 
check your air filter hose to see if its cracked. i had the same problem with my protege.

Nope, dont have that problem... all metal duct work

take it out and inspect, you can also send it out to get flow tested/cleaned. it was 15 bucks an injector for me when i did it

How long did that take...? I cant aford to have my car down for really to long. I may just run some injector cleaner through it
 
Nope, dont have that problem... all metal duct work



How long did that take...? I cant aford to have my car down for really to long. I may just run some injector cleaner through it


well use that as a last resort, check charge pipes and all that jazz
 
well use that as a last resort, check charge pipes and all that jazz

I literally just had a book lest test done and all is good except the TB leaks at the shaft. I have no idea if that could be causing my issues or not. No junk yards in my area have a good TB that I can rape off another car yet.
 
what boost are you running and what ems? Maybe it's a tune issue. I through the P0171 only when the Split second is on the car, when I remove it no CEL
 
I got that also. Did you check to see if the O2 sensor may have gotten loose (drawing in air) or a small leak near the injector/fuel rail?

Those where the two things that solved my problem.
 
what boost are you running and what ems? Maybe it's a tune issue. I through the P0171 only when the Split second is on the car, when I remove it no CEL

Stock tune, stock ECU... nothing extra and only running 3lbs on stock turbo. lol I need to re-adjust the WGA its to loose.

I got that also. Did you check to see if the O2 sensor may have gotten loose (drawing in air) or a small leak near the injector/fuel rail?

Those where the two things that solved my problem.

Ill have to check those when i get some time and the car is cool.
 
Just what you didn't need, another MSP joy experience!
Something else that can trigger that MIL:

MAZDASPEED - WHISTLE NOISE AT IDLE, FUEL CUT UNDER BOOST, MIL ILLUMINATED,​
DTC P0171 SET

Check engine light on with P0171 - FUEL TRIM SYSTEM TOO LEAN stored in memory.
The above mentioned conditions may be the result of a ruptured waste gate actuator diaphragm. To determine​
if this is the cause follow the repair procedure as described below
 
Well I know mine isn't the WGA since I have a Forge and it started not to long after it was installed with a ruptured stocker....
Another thing I've read is that the p0171 CEL could be caused by a cracked mani. I actually have an extra good mani sitting here but really have no desire to deal with installing it.
 
Just what you didn't need, another MSP joy experience!
Something else that can trigger that MIL:

MAZDASPEED - WHISTLE NOISE AT IDLE, FUEL CUT UNDER BOOST, MIL ILLUMINATED,​
DTC P0171 SET

Check engine light on with P0171 - FUEL TRIM SYSTEM TOO LEAN stored in memory.
The above mentioned conditions may be the result of a ruptured waste gate actuator diaphragm. To determine​
if this is the cause follow the repair procedure as described below



No I got my joy experience today taking my Uncle to the air port... ******* turbo X's BPV litterally came apart cruising down the highway! I had been on the highway for about 20 min when it came apart.. I heard somethign hit the floor and was boucning behind the car and about 3 sec later the car died.... Still dont know what that was.. might be the inside to the BPV....Thankfully I found the cap due to it being attached to the vac line....

Id have to check my WGA but last week it was fine. lol Still haven't had a chance to test anythign yet.
 
I've also read that a cracked manifold can be the cause. I get the same code off and on, and I know I have an exhaust leak at the manifold, but I'm also going to replace the wga and vacuum lines when I have time to install my steed.
 
Yeah the only way I'm ever going through all the trouble of removing that mani again is it I'm tossing on a steedspeed or Thunder. Its just not worth the effort to me to just install another stocker.
 
Yeah the only way I'm ever going through all the trouble of removing that mani again is it I'm tossing on a steedspeed or Thunder. Its just not worth the effort to me to just install another stocker.

LMAO same here not that it was hard to do or anything. Thats also one of the reason why im only boosting 3psi. lol
 
Lean codes are usually because you are sucking in unmetered air. My wife's car had this exact code because the idiots who changed her oil pulled out her air filter to try to sell her a new one and dislodged the intake enough the engine could suck in air past the MAF.

So yes your TB leaking could very well be causing the code. It also could very well be bringing your boost down to 3psi. Get that fixed ASAP.
 
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