ajack

Truck: 2011 FX4 Ecoboost w/ 37K miles

I'm getting a consistently lower long term fuel trim on bank 1 reading on my torque scanner. Bank 1 consistently reads about -15% while bank 2 reads about -7%.

From what I understand negative fuel trim numbers mean it's running rich and the computer is giving the motor less fuel via the injectors on that bank. A consistently -15% bank1 seems off to me especially since it's nearly always double bank 2. I mentioned this to my dealership and they don't seem to care if it's not throwing a code. I'm just looking to get on top of an issue if one does indeed exist. Both cats read the same temps and I've changed my plugs. I get about 13.5 MPG city. I'm wondering if this could be a fuel in the oil or PCV issue maybe?

Is there a reason these motors would show these readings under normal conditions or should I begin digging deeper and press the issue with the dealership?

ajack

Bump for thoughts? Anyone else check their fuel trims lately?

BucketMan

Do you smell fuel in the oil, even more so than what's expected with a DI engine?

Can you monitor A/F ratio?

Some have reported engine failure due to a stuck injector flooding a cylinder. Any rough running or misfire issues?

t76mach

Any p codes? if not then I wouldnt worry about it.

woody3

There is a serious "community wide" misunderstanding regarding the condensation issue. It exhibits at times other than those that result in a CEL or even the feeling of the engine "bogging" down.



The base cause for condensation is the fact that there is a pressure drop between the CAC inflow and outflow plumbing, even at moderate cruise levels. The longer you cruise without enough throttle opening to "wash" the condensate into the intake manifold the more it is that a CEL will result once you go "WOT"


But what about the times post a shorter cruise period with high Rh when you go into acceleration and there is maybe only a "Teaspoon" of water in the CAC outflow plumbing?


Not enough to cause a misfire but with a high likelihood of extra oxygen content reaching the A/F mixture sensor.


Water = H2O, vaporizes, 1-3% molecular separation under the pressure and heat of combustion, the A/F mixture sensor detects unburned oxygen in he exhaust flow and adjusts, enriches, the long term fuel trim accordingly.

maplelakeduckslayer

I dunno I'd say -15 is a ways off, mine are both around -7 to -6. I'd clean your MAP sensors and IC and see if anything changes. And pull plugs again to check and make sure they are fine.

ajack

I just changed the plugs. Not change yet to the LTFT but it's only been a couple hundred miles. The old ones had big gaps but I wasn't getting any misfires. If the MAP were dirty would that effect both banks rather than just one side? And if it were an intercooler(CAC)/condensation issue again wouldn't that effect both sides?

bignfast

My first guess would be the o2 sensor for that bank then if that wasnt the issue i would look at the injectors, both banks should read somewhat close. With negative fuel trims the pcm thinks there is a lean condition and is adding fuel to correct. If the o2 sensor is fouled, faulty, ect. It may be adding fuel for no reason (causing an actual rich condition) this could have a negative affect on fuel mileage.

s_vares

Interesting...

Subscribed.

woody3

Only Ford can tell why but one side is predominant insofar as condensation effects.