P0171 2014 Impreza

[Ddim]

Have been chasing down a P0171 code, I’ve put new
Injectors
Fuel pump
New throttle body gasket
New intake manifold gaskets
I’ve inspected every hose, no vacuum leaks showing through several smoke tests. No exhaust leaks. Cleaned the throttle body.

Took it on two, one hour drives yesterday on separate occasions. Took it for a 3rd shortly after the second and while getting on to the interstate check engine light came on for P0171 once again.

Took it to the Subaru dealership to get it looked at. They don’t find anything wrong. No leaks and sensors reading as they should.

So they suggested a fuel induction service. $496. Don’t have high hopes that this will fix my issue!
Will find out tomorrow, they said they will do that and then retest.

Thought and opinions?

 

[bmart]

Google Search

 

[Rattlenbang]

MAF sensor or 02 sensor are used to measure and correct fuel trims. Trying cleaning the first, maybe replace the second.

 

[william liming]

Clear out the memory and try again .
Disconnect batt for .5 hr , let it relearn and test for 100 miles

 

[keith3267]

Induction service is to clean the injectors. If you just put new ones on, you certainly don't need that. What the P0171 code is telling you is that the pulse width to the injectors on bank 1 has had to be increased by 25% or more from the expected amount programmed into the PCM in order to achieve the optimum A/F ratio. The engine is running is NOT running lean so no damage is being done, it is just taking more fuel than expected. BUT, the computer does not actually measure the fuel being injected, it is estimating the fuel by calculating the fuel pressure, the ml (milliliters) per second of the injector and the pulse width. It uses the factory specs for the first two, only the pulse width is measured.

So basically, one of the first two specs could be off, i.e. fuel pressure not correct or clogged injector, or unaccounted for air is getting into the intake manifold. It is also possible the MAF has become inaccurate or the O2 sensor itself is not giving an accurate reading.

 

[william liming]

Clean with fuel cleaner