RESOLVED: SES CODE P1092 [P1190] [BMW 235]

[Wayne's World]

Hey guys - need some help, especially from the techs or more technically inclined than I.

'06 X5 3.0L, auto, 90K miles

Problem started at 87K miles
Since the problem started, I've done a 60K maintenance.

FINAL UPDATE: Resolution provided in post #20.

[mrbmwx5]

at 87k miles you might as well do the basic tune up

[Wayne's World]

Thanks for the reply. I was considering just doing a basic tune up anyway but since the coil packs aren't part of that routine - I didn't want to go blowing money on everything else other than the source of the problem.

[Wayne's World]

To address the codes and in getting a tune up done, I've got the following planned for next weekend:

New cabin microfilter
New Fuel filter
New Oil Separator/Crankcase Vent Valve/PCV valve
Cleaning the ICV, MAF sensor & throttle bodies
Crankcase/oil system cleaning w/Berryman's B12
Intake valve cleaning w/Lubro Moly Ventil Sauber
Fresh Oil & Filter change
VANOS Seals replacement (My X is the I6)
Valve cover gasket replacement
New plugs (NGK Iridium)
New boots for the coil packs

New front brake rotors
New pads & sensors all around
Brake fluid flush

Air filter and both O2 sensors were replaced by the dealer less than 1K miles ago so not touching those.

I think the new plugs, new boots for the coil packs, new fuel filter, oil separator, VANOS seals and cleaning of the MAF sensor should all contribute to ending my woes with the SES light and my air/fuel metering probs & this new misfire/low fuel code. I've also confirmed that the intake tract doesn't have any cracks but once I pull it all out, I will double check.

[Wayne's World]

So out of the list above, I only managed to do the following due to time restrictions, mostly.

New rotors on the front
New pads all around
Brake fluid flush

New microfilter
Crankcase cleaning. Used Seafoam instead of Berrymans.
New oil & filter
Valve cleaning using Lubro Moly Ventil Sauber
Cleaned the ICV, DISA, MAF and Throttle body
New plugs (NGK Iridium IX) - no noticeable difference. BOSCH/BMW plugs were in it before although I was under the impression that BMW used NGK as was the case for my E39.

Boots for the plugs were the wrong ones but after inspection, the existing boots looked pretty good.

Planning to do the VANOS seal replacement and a cooling system flush next weekend. That should be a good 7 hours. With that will come the valve cover replacement.

Replacing the oil separator looks like the job from hell. After pulling out the air intake boots and ICV, I still couldn't see the oil separator clearly enough to actually work on it.

The fuel filter has boggled my mind. It seems as if there is a belly pan underneath the tank but as to how you get it down, I have no clue. There are bolts and screws which are easily removed but on my '06 there are also what looks like pop rivets that I have no clue how to remove.

[lo_jack]

Did you get the fuel filter replaced yet? I am guessing that is what the codes were for. 02 codes can come and go as the computer tries to learn and compensate for abnormalities in the equipment or environment. I would not romp on it if you get the lean/low fuel code again. Don't want to burn it up if that is actually the case. There is a schrader valve on the fuel rail that I believe you can put a mechanical gauge on and see for yourself if you really are getting fuel at the rail, and more importantly if you get correct pressure at WOT. One problem though...you will have to figure out what fuel pressure is ideal, because I don't think I have ever seen that number before. I would be curious to find it though.

[Wayne's World]

No never did yet but I do feel the same way. The CEL/SES went out 2 days ago but came on again the following day. I've been romping on it quite a lot actually only because i've got fresh plugs and some wicked oil in there. But the fuel filter has boggled my mind on how to get to it. I started to take out the bolts for the belly pan, maybe about 8-10 of them and then got around to the side nearest the driveshaft and there are pop rivets there. No bolts. And it's firmly in place. A co-worker of mine bought the repair DVD off ebay and was going to make me a copy. I was going to see if that had the procedure documented before throwing down for the Bentley.

[Wayne's World]

OK so it's been a while but I'm still dealing with this problem but have done much since. The P0313 code has gone away.

The P1092 has persisted.

HISTORY
Since originally deciding to give the car a large 60K tune up, I've replaced the following within the last 3K miles that I feel would contrbute to solving the problem:

*New Valve Cover Gasket
*Oil & Filter Change [Total Quartz INEO MC3 5w-30]
VANOS Seals Replacement [Seals & VANOS Body Gasket]
NGK Iridium IX plugs
Fuel Filter
CCV Valve & Hoses
Coolant drain & fill [BMW Coolant & Distilled Water]
New OE BMW air filter
New Pre-cat Bank 1 O2 sensor replaced @ 86.5K miles by dealer, prior to me taking ownership of the vehicle.

Other items that should have no bearing on the code are:

New Brake Pads all around and new rotors up front
Brake fluid flush
New Transmission fluid [Valvoline DEX VI & filter | Drained and filled 2x]
Drain and fill of front and rear differential with OE BMW fluid [Castrol XAF-XJ]
Drain and fill of transfer case with OE BMW fluid
Drain and fill of power steering fluid with ATF
New cabin air filter
New OE 17" size tires

As far as service goes:

2 Fuel System Cleaners [20z Chevron Techron Concentrate & 15oz Redline SI-1]
Reset throttle adaptation
Cleaned MAF sensor with CRC MAF Sensor Cleaner
Cleaned ICV, DISA & Throttle body butterfly valve
LubroMoly Ventil Sauber via the brake booster line to clean top end

In removing the air ducting to clean the intake components and replace the CCV, I checked the hoses for cracks but found none. I paid attention to the elbow/accordian that shoots off to the ICV but it was OK.

The items I starred (*) above are what I believe might possibly be causing the condition. Although I torqued the valve cover gaskets down to spec, it could possibly still be leaky. I have not had a smoke test done yet. The oil I've used seems to be burning quite fast, about 1.5 quarts in 2000 miles. I'll be switching to German Castrol this weekend. I should also add that I only use Shell VPower (93 Octane).

TROUBLESHOOTING
BMW's P1092 code is defined as: Pre-Catalyst Fuel Trim Too Lean Bank 2
This is similar to the generic code of P0174. From OBD-CODES.com, P0174 is typically a vacuum leak after the MAF, a dirty MAF or a clogged fuel filter. OBD-II Trouble Code: P0174 System Too Lean (Bank 2)

Using my MAC Tools ET50 code reader, I was able to capture the freeze frame data, just today after clearing the codes last night. I have cleared it again and I'm certain it will come on again, so I will do the freeze frame again to determine if the values and conditions are similar.

This is where I really need your help, especially the techs. I have no clue how to diagnose this using this information but I figure someone out there might be able to help with this information.

Calculated Load : 47.84%
Coolant Temp : 87.0 C [188.6 F]
Engine Speed : 2285 RPM
Vehicle Speed : 59.00 kmh [36.7 mph]
Ignition Timing : 26.00 BDTC
Intake Air Temp : 30.0 C [86.0 F]
Mass Air Flow : 34.69 g/s
Throttle Position : 18.82%

Short term fuel trim Bank 1: 4.67%
Short term fuel trim Bank 2: 3.89%

Long term fuel trim Bank 1: -3.91%
Long term fuel trim Bank 2: -3.91%

At the time I recall the light coming on, I was slowing down to approach a traffic light. The outside air temperature as reported by the dash/cluster was 23.0 C [73.4 F]. Fuel mileage is a steady 18.0 MPG combined as confirmed by the dash/instrument cluster and the last fill up calculation. Range upon a fill up today showed 484 miles. Only noticeable driveability has been due to the oil burning and engine doesn't feel as smooth.

To add insult to injury - this is the strangest part of all. A coworker of mine that I typically go to lunch with every now and again, will get in the car, we'll drive over to wherever, come out and the light goes off. Meanwhile, it's been on for days. This has happened 3 times now. I know it's ridiculous but it was significant enough to mention it. I have NO IDEA what this has to do with it. And then on my way home, the light comes back on again. Go figure!

[Wayne's World]

So after doing some reading on how to read fuel trim data [I found this website very useful in understanding fuel trim: Driveability Corner | Motor | Find Articles at BNET]

It looks like it could potentially be a bad MAF sensor however the fault should've triggered both banks to run lean. Given the history of the vehicle where the Bank 1 O2 sensor was already replaced, this may be pointing to a bad or soon-to-be bad Bank 2 O2 sensor.

I'm going to swap the O2 sensors tonight and see if the code changes. Also, the light came on again today on the way into work but at highway speeds. I'm going to pull the freeze frame data later and post as I imagine the operating conditions are different.

[amacman]

i aint no expert but the ignition timing at 26.00 dont sound right .
that could be crank sensor or cam sensor or possibly something to do with valvetronic . also , is the crank vent system functioning correctly