True MYSTERY problem. p2096 Can you help me?

[Persian]

Background:

For the past winter, I was going to and coming from school with a jammed open Thermostat. (freezing my ass off)

I didn't have the time to look after this due to an intensive program I was in. About 80 hours per week at school.

Fast forward to March where my sticker expires and I need an emission...


I had the codes:
P0125 (thermostat open code for BMW).
P0313 Misfire with low fuel
P2096 Post Cat Fuel Trim System Too Lean Bank 1.

OR in BMW language Trimming, oxygen sensor behind catalytic converter, bank 1.

I purchased the thermostat and a MAF (preventative) straight away. I replaced both of these. MAF is VDO Siemens.

All codes cleared and p2096 kept coming back.

So I purchased and put in a new o2 sensor after reading my voltages and seeing that the sensor was "stuck" at a voltage.

While I was at it I checked all the hoses and noticed there was a hose with a slight crack and I fixed it(it isn't part of the vacuum, but it does come into play when the car is NOT idling, it is connected to some solenoid or stepper motor).

The new sensor surely worked.

But now the code continues to come back, AND O2 readings spike at 0.1 to 0.6~0.8 while driving.

What can the problem be? Is it the DME? Is there a non-computer reset which may work?

This is a video from someone else whom appears to have the same issue!

https://www.youtube.com/watch?v=Ndif0o24VsU

I left him a message, hoping to hear back...

Car runs like a DREAM. 265,000 kM

PLEASE HELP ME

[Persian]

Bump

[Persian]

I have made an attempt to wipe the ecu or dme through the battery trick. No avail.

Please help.

[SlickGT1]

Battery trick wont work on these cars.

So that code can happen for a few reasons. Shorted sensor. Shitty maf. Leaking injector. Or what i am thinking is an exhaust leak. The code is telling us too much air, not enough fuel, lean.

Could be unmetered air post maf, like a cracked elbow in the intake path. Take off the DISA valve and inspect it just to be sure as well. Should be fairly easy to do.

I am thinking air leak, or exhaust leak simply because it runs like a champ otherwise. Maf would throw a code, usually. And o2 sensor would also have its own code.

[Persian]

Originally Posted by SlickGT1

Battery trick wont work on these cars.

So that code can happen for a few reasons. Shorted sensor. Shitty maf. Leaking injector. Or what i am thinking is an exhaust leak. The code is telling us too much air, not enough fuel, lean.

Could be unmetered air post maf, like a cracked elbow in the intake path. Take off the DISA valve and inspect it just to be sure as well. Should be fairly easy to do.

I am thinking air leak, or exhaust leak simply because it runs like a champ otherwise. Maf would throw a code, usually. And o2 sensor would also have its own code.

Hey thanks for he reply. I've checked these and tried to pressure the system at all inflow points. System is running fine and no cracks were visible via spray checking at those intake pipes.. What bothers the hell out of me is that my o2 readings are 👌 bang on. See this video I've made Bmw e53 x5 m54 p2096 fuel trimming lean - YouTube

The only other point which is interesting now is that the car blows a slightly funny smelling air at idle in 2-4 degrees Celsius even after being warmed up. I'll have a vid of this shortly.

[SlickGT1]

Have you tried putting injection cleaner in yet? Bad gas can do this. Just talked to my BMW guy, he has a shop. He said it could be the fuel and he has seen this issue on Porsches with a bad fuel press regulator.

[Persian]

Originally Posted by SlickGT1

Have you tried putting injection cleaner in yet? Bad gas can do this. Just talked to my BMW guy, he has a shop. He said it could be the fuel and he has seen this issue on Porsches with a bad fuel press regulator.

Is the stuff effective? going to pick some up now

[Persian]

Hey slick. Thank you for your suggestion. I have put in a bottle of rislone. Driving on the highway I see p2096 pending after 20km but not stored.

[Persian]

here are some freeze frames

http://i.imgur.com/BfporB8.jpg

http://i.imgur.com/lN2b7nJ.jpg

readings at idle as of now

http://i.imgur.com/CatqWZF.jpg

[SlickGT1]

Fuel trim 1 at 7% is a bit much for 2300 rpm. Isn it pretty much telling up there is not enough fuel and the computer is increasing it.

Clogged injectors, bad fuel filter, bad fpr, bad gas would be my areas to look at. Can you check the fuel pressure? Inpa can read it.