I’ve been chasing down a P2096. My scanner shows LTFT to be ~ +20% when idling but goes down to ~6% on the highway. Here’s what I’ve done so far:
1. Fuel pressure was low, reading ~40psi. I was having some cold start issues. Repair manual says S should be ~50psi and non-S 40. I replaced with a new fuel pump and cold start issue seems resolved. The old pump had no part number on it at all so I wonder if maybe a previous owner swapped in a cheap Chinese part that was made for a non-S?

2. cleaned injectors

3. Performed exhaust leak test and found huge leak at the manifold where the 4 collectors merge. Replaced with new part and confirmed that leak is gone.

With that, I am still reading LTFT of >20% when idling. What gives? Could it be I need to reset the fuel adaptations?

 

Resetting would by my first advice yes.

Is your bypass valve working ok?

 

it should be working fine. I’m not having any driveability issues. Is there some connection between p2096 and the bypass valve?

 

The bypass valve has influence on fuel consumption

 

What is the STFT (short term) reading? It takes some time for the ECU to calculate the the LTFT (Long Term).

 

When idling, STFT ~6-10 % and LTFT >20%. When on the highway at steady speed, STFT ~0% and LTFT ~6%. The fact that the trim numbers improve when engine is revved or driving lead me to think it's some kind of exhaust leak.

 

From what I have read, our cars are in open loop at idle... which means no fuel control

Bryan

 

Usually:
-Open loop at idle & WOT
-Closed loop at partial throttle/load

 

You may have a damaged catalyst, that why you have bad LFT and get P2096 fault code.

 

manifold was replaced due to the leak.

 

Not the same thing, but I chased down a p0171 for a year or so before I finally noticed that the previous owner had changed the routing for the bypass valve. They'd connected the bypass valve via a new pipe to a tee on the fuel pressure regulator line. I took that off and reconnected the bypass valve as it should be, and the code went away. The symptoms were crazy LTFT readings when under heavy load - accelerating up a long hill on the freeway, for example. My advice: check for clever previous owner mods and reverse them.

 

Reset fuel adaptations if you can otherwise the ECM/PCM or whatever Mini calls the engine control module will have to slowly adapt to the now repaired exhaust manifold that was likely supplying unmetered air for the O2's to pick up.

Once adaptations are reset, the ECM will operate from a base fuel map and adjust STFT/LTFT from the O2 readings which should then remain within specifications if the repair is complete and/or correct.

 

That’s good advice. I’ll take a look.

 

how long does it take to slowly adapt? I have a Foxwell 510 but it doesn’t seem to have an option to reset fuel adaptations on the R53. I’ll try updating the software to see if they added that ability but I’m not holding my breath.

 

Also known as the "VGS" mod (vacuum gain system). I tried that myself, but reverted in the end. More info here: https://www.northamericanmotoring.co...ystem-vgs.html


And you connect the new splitted line to the actuator of the bypass valve (and cap off the existing connection)

 

Just want to give some insight for people who may be having a similar issue. My GP has been throwing a P2096 for a while now, and I've been slowly troubleshooting the issue. First was a broken exhaust header. I changed that, and while the long and short term fuel %'s decreased, they still were +. I used this site to troubleshoot as well: https://www.vehicleservicepros.com/s...equipment-news

I then started looking at the voltages on the O2 sensors and took a bit of a gamble, and replaced both front and rear O2 sensors with new NTK sensors. I also downloaded INPA and used the how-to's on this site to install them on my laptop. I was able to reset my fuel trim adaptations, and with the new o2 sensors, the car's MPG has improved from low 20's to high 20's and low 30's! The car hasn't thrown a code in the last 3 drives - it usually throws it after the second restart - and hopefully it will stay off. Not sure if its related, but I just started having a cold start issue - car starts, then bogs and misfires and then dies - second key on restart and the engine starts right away and is fine. I've already replaced the fuel filter last year, and the car runs fine after this. Anyway, I'll keep troubleshooting it, but at least so far, my P2096 hasn't come back! Hope this helps anyone!