Brand new car, engine running rich?

[gathermewool]

 

[gathermewool]

Is it ideal? No.
But +/- 5-10% is fairly normal for stock cars.

Cobb must have changed their stance. Their latest literature from several years ago states that +/_ 10% is acceptable. With that said, I wouldn't consider being right at the edge of acceptable normal.

@Noobie when was the last time you threw in a bottle of fuel injector cleaner? Cleaned your MAF? With only 3k miles probably never. Might be worth a shot.

Any mods?

 

[gathermewool]

But it isn't actually running lean as the Fuel Trims are not maxed.

IMO, running lean or rich is relative to fuel trims, so yes, the OP is running rich (after correction to neg LTFT). At least in my previous Subie, fuel trims didn't carry over into WOT, open-loop fueling, so a lean condition might affect WOT fueling in a negative way. Running rich while in closed loop would result in a richer OL, so no real issue there...

 

[MattPersman]

This is why they don’t show these type of readings on factory gauges because you would have a string of them at the dealer “running rich”

there are sooo many factors it’s nice that the ECM CAN adjust it

 

[ARCOgraphite]

The reason why i started monitoring the engine is because after i leave the car off for a couple hours (Lets say, 6 hours or more) sometimes it would start smoothly then after 5 seconds of smooth idling it starts to choke for 5 seconds (RPM drops, engine feels as if its misfiring or stalling) then the ECU adds some throttle and it recovers and continues idling smoothly.

Couldnt believe a brand new car is giving me rough idle issues. Previous korean econobox fared much, much better mechanically, didnt give me a single mechanical issue during the time i owned it.

That sounds odd. Maybe you got some bad fuel . Or rabbid mice knawing on wiring.

I bought a car recently that had a large mouse family living in the aircleaner!

Pounds of horsehair and chewed and fluffed rags

Hope it settles out - but doesn't sound right or good.

 

[clinebarger]

IMO, running lean or rich is relative to fuel trims, so yes, the OP is running rich (after correction to neg LTFT). At least in my previous Subie, fuel trims didn't carry over into WOT, open-loop fueling, so a lean condition might affect WOT fueling in a negative way. Running rich while in closed loop would result in a richer OL, so no real issue there...

During WOT runs.....I just about guarantee there was enough built-in Enrichment that it never leaned out......12:1 to 13:1 AFR is pretty typical. Of coarse this assumes that the fuel system, feedback sensors, & mechanical engine as a whole is in good working order. I'm strictly speaking the Fueling Map/Calibration.....They're not perfect but things like power enrichment are there to keep the engine from self destructing.

 

[2EHA]

when you’re frequently pegged at +\- 20 you have a problem

when you have double digit LTFTs you may have a problem

otherwise just relax and take it easy

 

[ARCOgraphite]

Cobb must have changed their stance. Their latest literature from several years ago states that +/_ 10% is acceptable. With that said, I wouldn't consider being right at the edge of acceptable normal.

@Noobie when was the last time you threw in a bottle of fuel injector cleaner? Cleaned your MAF? With only 3k miles probably never. Might be worth a shot.

Any mods?

I just thought of a past experience, my 2014 Rogue came with an "over oiled" AIR filter from the Japanese factory - I mean this thing was dripping with oil. A container shipped overseas vehicle - like the OP's.

The SUV was only getting about 22-23 MPG. Tailpipe was black inside ( unlike Fords that always seem gray )

Then I thought, Maybe the MAF is dirty. I removed it, changed pout teh air filter, and I clean the MAF with CRC MAF Cleaner and the car ran much better after a sort period of adjustment of five or so hours of operation.
It had crisper light throttle response and nice down low torque. Gas Mileage was same though

I would check all air plumbing to insure it is air-tight. Then to the dealer for a EEG.