P2096 Recurring Check Engine Light after Fill up/Car Wash -- Troubleshooting help
 

Right -- Hopefully a decent thread title for searches.

P2096 Target A/F feedback system too lean ON 2 Fuel system ´
(See DTC P2096 )

Situation:
Fill up with 91 and purchase a touch-less car wash (with the under carriage wash)

I had to wait in line for the car wash, car was running the whole time (no cel).
(I don't believe it's a bad gas issue but its a variable that needs to be identified)

Entered car wash, car was running, no problems.
Exit car wash and didn't even get a 100 feet when the CEL came on.

Vehicle background:
Custom Turbo setup
80,000 km's
BHR Coils
Brand new plugs not even 500 km's on them
No catalytic
Ambient temperature 30f to 38f

Modified air filter location is on the top of the frame bumper on the passenger side basically in front of the ECU.
This location is not ideal for preventing contamination from water.

Vehicle Behavior
I knew I was taking a chance going through the car wash and getting the filter wet.
So I pulled in to my work and lifted the hood and yeah ... water everywhere and filter was wet.
Now I'm at work all week for a services meeting so I'm not able to come home.
I clear the code and it continues to come back.

The thing that has me confused is that my AFR's (I have a gauge to monitor this) where perfect in cruise and idle before this (14.7).
Now I'm running rich about 0.5 afr in cruise and idle.

The code says lean?
P2096 Target A/F feedback system too lean ON 2 Fuel system ´
(See DTC P2096 )

Can someone enlighten me on this?
And I've not been able to figure out if this is a Front O2 sensor problem or a Secondary O2 sensor issue. To me it's not glaringly evident.

MIL Freeze Frame capture:
Fuel system 1 = Closed Loop
Calculated Load = 29%
Engine Coolant Temp = 77c
STFT Bank 1 = 4.6%
LTFT Bank 1 = 0.0%
Engine RPM = 3030
Speed = 71 km/h
Ignition Timing = 31deg
Intake Air Temp = 10c
Maf = 34.47 gm/s
Throttle Position = 20%
Secondary Air Status = off

Troubleshooting
I plan on doing these one at a time to see if I can hit the exact item that is throwing the MIL

1) SEARCH RX8 SITE!!!!!!!!!!!!!!!!!!!
2) Clean Air Filter
3) Clean Maf
4) Clean/Check/Reset ESS

Results
I thought this post was interesting while I was searching for info on the P2096
https://www.rx8club.com/series-i-trouble-shooting-95/engine-code-p2096-resolved-issue-217828/

Funny typo in this post
https://www.rx8club.com/series-i-trouble-shooting-95/help-p2096-post-catalyst-fuel-trim-system-too-lean-bank-1-a-210793/

Interesting tid bit at as well
https://www.rx8club.com/series-i-trouble-shooting-95/p2096-post-cat-fuel-trim-system-too-lean-bank-1-a-220451/

However I came to this thread which had another item that my car also is experiencing that I've not mentioned.
https://www.rx8club.com/series-i-trouble-shooting-95/reaccuring-p2096-226774/

I get the same thing.
It's been like that since the turbo install. Everyone says vacuum leak, and I thought that as well ... but if looked and looked and taken shit a part and clamped and zip tied ... I can't find anything.

The only thing I would add to this is that my car does not show this behavior until the engine is fully hot.
If the engine coolant temp is around 70c it will not stall however once it gets nice and warm 80c + it will stall under the above conditions.

So the original OP's engine finally thru an apex seal shortly after posting that thread.
This does not make me happy but I thought it my be relevant so I'm noting it here.
I also found it curious that I have the exact same stall problem, which only started once I installed the turbo kit.

I do not know if this symptom is part of the P2096 mil issue ... but I will document that problem/troubleshoot progress here as well.

Questions:
Why am I running richer than before the MIL?
Is the lean condition being reported from the Front or Rear O2 sensor?
Stall issue on hot engine over 3k rpm, thoughts?
Any other ideas advice or something I should look at?



I reflecting on this thread before I hit the submit button ... not sure if this is worth doing .... I'll delete the thread if it turns in to a shit pile.

From my understanding, the rear o2 only reports how the cats doing. It should not effect on anything, even if you unplug it, except getting a cel.

My only experience with a car stalling like you described (3k rpm drop) was a bad maf. But this was on a totally different car (04 grand am gt), so it might not apply here.

Sorry forgot to add that I have the Cobb and most of the codes for the rear o2 turned off.
I thought??

I have a spare maf but that would mean re-tuning.
I will keep this in mind thanks, but I hope it's not a faulty Maf (cross my fingers).
Ugh at re-tuning

I also have that DTC 2096. Cleaned MAF, replace rear o2 sensor, found no vacuum leaks, cleared the DTC, After driving about 100mi. I got DTC 2096.

Thanks for the input.
Defiantly a recurring issue for some people.

I will have some time tomorrow to start troubleshooting.

Odd sequence. Is the oil catch can perhaps open to air and sucked in water to places water shouldn't be?

Interesting...
Yes it got wet. I have it located near the front of the engine bay.

I didn't inspect it closely but I will check it out ...

Anyways, its' a good idea. I will check all those connections.

I'll have a few hours in the morning before work, I'll try and clean the air filter and inspect hoses.

thanks

Hmm, I know your car is way more modified than mine, but if you like I'll hop in mine today and try to freeze frame the same data at 3030rpms and 71km/h. Maybe this would help?
I know your turbo, but both engines are the same so as long as your not boosting we should be sucking up about the same amount of air.

Thanks 1.3 LOF
The g/s should be close as long as the load is the same as well.
What the hell might as well try if you like and we shall see.

Update:
I dried the filter and went for a run.
The good news is everything seems fine now. No MiL and the AFR's are good.

So that was easy, not quite what I expected.

I'm having problems with my electronic copy of the Rx8 workshop manual but if I can I will place the troubleshooting section for the P2096 MIL here....

In a nut shell ... just about anything can cause a P2096

Found P2096 issue.
 

Changed the gaskets at exhaust manifold & catalytic converter. Looks as if the previous gasket had deteriorate. I believe the gasket cost under $2(rock auto parts). So far 300mi and no DTC P2096.