2015 fusion titanium 2.0 ecoboot p0171running lean code

[Tom5170]

2015 titanium 2.0 ecoboost 113,800 miles. No mods all stock. Today I was running errands for about 3 hours driving around town. Got home and then went to leave again, started the car, and check engine light was on. Scanned it and code p0171 came up. Only code. As soon as I clear it, it comes back. I have no drivability issues whatsoever. No idle issues, etc.

 

I've watched a few youtube videos and read comments. One video said it was fuel injectors and lots of comments some from ford techs are saying p0171 is 99% of the time fuel injectors on the 2.0 ecoboosts. I always run regular gas - no premium and no midgrade.

 

My short term fuel trims are around + or - 5% at idle and wot. My long term trims are around 28% at idle... and at wot driving, long term will drop to about 10% and then jump back up to 28% as rpm's drop.

 

Any idea?

Edited December 4, 2020 by Tom5170

[bbf2530]

45 minutes ago, Tom5170 said:

2015 titanium 2.0 ecoboost 113,800 miles. No mods all stock. Today I was running errands for about 3 hours driving around town. Got home and then went to leave again, started the car, and check engine light was on. Scanned it and code p0171 came up. Only code. As soon as I clear it, it comes back. I have no drivability issues whatsoever. No idle issues, etc.

 

I've watched a few youtube videos and read comments. One video said it was fuel injectors and lots of comments some from ford techs are saying p0171 is 99% of the time fuel injectors on the 2.0 ecoboosts. I always run regular gas - no premium and no midgrade.

 

My short term fuel trims are around + or - 5% at idle and wot. My long term trims are around 28% at idle... and at wot driving, long term will drop to about 10% and then jump back up to 28% as rpm's drop.

 

Any idea?

 

Hi Tom. You can start here: https://www.obd-codes.com/p0171

 

A lot of possible causes other than the fuel injectors.

 

In addition, perhaps one of our tech members will jump in with more guidance/advice.

 

Let us know how you make out and good luck.

[FXT]

for the price of it I would run some fuel injector cleaner through it. and visually check the items listed for that code.

keep clearing the code through a tank of gas.
if it persists maybe disconnecting the battery to reset the computer control settings, reconnect and follow the instructions in your user manual to have it relearn them fresh?

[Tom5170]

1 hour ago, FXT said:

for the price of it I would run some fuel injector cleaner through it. and visually check the items listed for that code.

keep clearing the code through a tank of gas.
if it persists maybe disconnecting the battery to reset the computer control settings, reconnect and follow the instructions in your user manual to have it relearn them fresh?

yeah i thought about running a bottle of techron through. I have no drivability issues. I looked twice under the hood for anything broken or disconnected and didn't see nothing. I just filled up on the 2nd (two days ago). 

 

I was looking at fuel injectors locally and they are expensive as hell lol like $120 per injector. 

 

I stress out every time something like this happens. I start overthinking every single possible cause.

 

 

This is one of videos I was talking about: 

 

Edited December 4, 2020 by Tom5170

[Tom5170]

is it possible to pull the plugs and see if any of one them are lean? would that tell me it could be a fuel injector issue?

[Tom5170]

I pulled all 4 plugs and all 4 were definitely lean

 

I'm still having no drivability issues. 

[FXT]

unless it was flooding the engine to a stall its gonna run and because of the sensors it throws the code because it is over (or under) threshold.

If you dont have much to throw at it, start with the cheapest things first.

Personally I would do a system reset and if the problem is not from skewed values in the computer, they will show again.

[Tom5170]

7 hours ago, FXT said:

unless it was flooding the engine to a stall its gonna run and because of the sensors it throws the code because it is over (or under) threshold.

If you dont have much to throw at it, start with the cheapest things first.

Personally I would do a system reset and if the problem is not from skewed values in the computer, they will show again.

So where is this info in the user manual that you speak of? i'll definitely try disconnecting the battery and see.

 

Tonight i dumped a bottle of sea foam fuel injector cleaner in the gas tank. On my next few fillups, should i use a different gas station and maybe use premium? And like i said i pulled all 4 plugs and they were all lean. I can't see anything broken or disconnected vac lines around the intake manifold.

 

My LTFT numbers are 28% at idle and go down to 15% wot.. then go to 28% soon as I left off the gas. My STFT numbers stay around 0% at idle and don't really go over + or - 7% wot. So STFT to me looks normal.

Edited December 5, 2020 by Tom5170

[FXT]

5 hours ago, Tom5170 said:

So where is this info in the user manual that you speak of? i'll definitely try disconnecting the battery and see.

In mine its under Replacing the 12V battery. You would just disconnect it for 30mins-1hr and reconnect.

 

5 hours ago, Tom5170 said:

Tonight i dumped a bottle of sea foam fuel injector cleaner in the gas tank. On my next few fillups, should i use a different gas station and maybe use premium? And like i said i pulled all 4 plugs and they were all lean. I can't see anything broken or disconnected vac lines around the intake manifold. 

 

My LTFT numbers are 28% at idle and go down to 15% wot.. then go to 28% soon as I left off the gas. My STFT numbers stay around 0% at idle and don't really go over + or - 7% wot. So STFT to me looks normal.

The computer stores values and supplies what is needed based on the information gathered in real time. As a basic theory, if the computer thinks less air is going in that really is, its going to supply less fuel.

I am just presuming the values are skewed based on how many miles its done and if you aren't finding anything else wrong visually. It is a normal procedure that is done when the battery is replaced because the values are lost and need to be relearned.

Its free so I would certainly give it a try.

[bbf2530]

10 hours ago, Tom5170 said:

So where is this info in the user manual that you speak of? i'll definitely try disconnecting the battery and see.

 

Tonight i dumped a bottle of sea foam fuel injector cleaner in the gas tank. On my next few fillups, should i use a different gas station and maybe use premium? And like i said i pulled all 4 plugs and they were all lean. I can't see anything broken or disconnected vac lines around the intake manifold.

 

My LTFT numbers are 28% at idle and go down to 15% wot.. then go to 28% soon as I left off the gas. My STFT numbers stay around 0% at idle and don't really go over + or - 7% wot. So STFT to me looks normal.

 

Hi Tom. In addition to the information FXT has provided, I would just add:

 

If you disconnect the battery, there is an Idle Trim Relearn procedure you need to perform to allow the PCM to relearn certain parameters. If you do not, there may be some minor driveability issues, until the necessary number of driving cycles and miles have been driven. This information, along with the Idle Trim Relearn procedure, is outlined in the same section of the Owners Manual that FXT mentioned above.

 

And as long as you use an 87 octane minimum fuel from a high quality fuel suppler, there is no need to use premium fuel.

 

Good luck.

[Tom5170]

I disconnected the battery for an hour. Reconnected battery connected my blue driver obd2 and pulled up live data as I started the car and did the idle relearn.

 

Immediately starting the car the Ltft was right at 28% idling with the stft going at -12%. Once warmed up the ltft stays the same at 28% and the stft goes to around +2% at idle. If I rev ltft goes down to 14% then back to 28% soon as I let off gas. I still have no drivability issues. So looks like system reset didnt do anything lol.

 

If it was an exhaust leak sucking in air, wouldnt this cause a rich condition and the car would run like crap? Like the o2 would be fooled by this and then add more fuel but since it's already getting enough air it would just be too much fuel and run rich? 

Edited December 6, 2020 by Tom5170

[Tom5170]

So today my ltft have been at 23% down from the usual 29%... and there are no codes pending and my check engine light is off. Yesterday after battery disconnect ltft 29% after driving for 30 miles. Today first start 23% been there all day.