P0154 & P1085 any ideas?

[JPR10]

P0154: 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)
P1085: Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)

Here's some background...

• M54 was replaced in April 2017 with a used M54 w/ ~100k miles
• Often times car/motor will shake during cold starts
• Was dealing w/ some battery voltage issues until I removed some extra wiring that PO had installed w/ a system
• Car starts up tonight (after sitting for a week), and a lot of smoke coming out of tailpipe... It was cold, so maybe that's why. The car itself wasn't responding well under throttle... It was hesitating so I drove back to my driveway and took my other car.
• A few hours later I go to start it and it chokes up, turns over but never fires (won't start)
• Checked for codes, and those 2 codes are now pending

Any ideas? Could low battery voltage cause other electronics/sensors to malfunction? How can I check it -- my cluster has pixelation issues, so I won't be able to do it there.

What are some other thoughts on diagnosis?

Let me know what you guys think.

[JPR10]

Any ideas? I plan to test my 528s battery in the 530 this weekend and will report back... Any other thoughts?

I will also try to start the car again tonight to see what happens. If I can, I'll post a vid.

[JimLev]

Any chance the cable to the O2 sensor got pinched or the cable is broken?

[geargrinder]

Is there some reason you're avoiding the obvious - i.e. bad O2 sensor Bank 2 Sensor 1?

That would affect mixture, potentially its been actually running rich as hell because DME was trying to enrichen mixture it falsely 'thought' is lean when in reality it is not.

And if so, perhaps the super rich mixture has now given you "M54 borewash syndrome" (damn that's coming up a lot lately).

[edjack]

#1. Go to Harbor Freight and buy a DMM.

#2. Measure the battery voltage. S/b 12.5+

#3. Measure the battery voltage at the O2 sensor. S/b 12.5+

[JimLev]

And if so, perhaps the super rich mixture has now given you "M54 borewash syndrome" (damn that's coming up a lot lately).

This must be the new answer for everything, like the Click & Clack "choke pull off" answer they gave 1/2 the callers.

[JPR10]

Ok here's an update. Sorry for the delay as life has a tendency of getting in the way sometimes...

Swapped a known good battery from my 528i to my 530i -- still no start. The 528i starts up and runs fine w/ the battery from the 530i: Ruled out battery/voltage problems.

Took some pics of 02 sensor 1, bank 2:

IMG_3922.jpgIMG_3923.jpg

Both the sensor itself, and the plug have this weird orange paint, or tint on it. Bank 1 sensor looks normal... PO must have changed it out w/ after market?

IMG_3920.jpg

I pulled up the engine cover and took a look at all of the wiring to see if there were any pinches or exposed parts... all looked normal to me.

Questions:
- Does anything look off in the picture of 02 sensor on bank 2?
- Should I just replace it (in pairs) or is there anything else for me to inspect?
- The car doesn't start now... The engine turns over and the starter is trying to do its job... Could the O2 sensors cause a no-start?

- - - Updated - - -

#1. Go to Harbor Freight and buy a DMM.

#2. Measure the battery voltage. S/b 12.5+

#3. Measure the battery voltage at the O2 sensor. S/b 12.5+

Given my previous post -- is it worth it to check the voltage at the O2 sensor? I've never done this, so a quick tutorial would be helpful. I do own a HF multimeter, lol but I've never put it to use.

[JPR10]

Is there some reason you're avoiding the obvious - i.e. bad O2 sensor Bank 2 Sensor 1?

That would affect mixture, potentially its been actually running rich as hell because DME was trying to enrichen mixture it falsely 'thought' is lean when in reality it is not.

And if so, perhaps the super rich mixture has now given you "M54 borewash syndrome" (damn that's coming up a lot lately).

What exactly is bore wash? I'm reading into it a little, and this could be the problem on the no-start... How serious is this? Is the remedy simple or complex/expensive?

[Mach540]

What exactly is bore wash? I'm reading into it a little, and this could be the problem on the no-start... How serious is this? Is the remedy simple or complex/expensive?

I've done some (very little) research and found mostly confusing information from people that obviously have no idea what they are actually talking about...... Just regurgitated internet babble...... We all know how that goes.
I did find this article that discusses "Bore Glazing," that sounds like it could be a likely candidate for what might be happening.

https://coxengineering.sharepoint.co...reglazing.aspx

(Read it quick.... It looks like MicroSoft (penis) will be deleting the page in the very near future!)

[geargrinder]

Yeah Machster, that's not the same. Borewash is when too much fuel washes down the cylinder oil film and the rings can't seal anymore. M54's are notorious for this problem as they age... Its exacerbated by the M54 having apparently tricky rings that get clogged up with gunk over time i.e. you probably couldn't borewash a new M54 with tight rings if you tried because there'd be enough seal to get the motor started then oil splash would be enough to seal them up again, but with aged motors the fuel has solved some of the gunk in the ring gaps and stuck the rings so they can't seal up so easily. This stuff is all over the E46 boards because they have so many more M54's than E39's so they see it more often.

Non-BMW explanation of the symptom in new engines.

https://www.hastingspistonrings.com/...faqs/fuel-wash

BMW M54 explanation, which turns into a sales-pitch for a (actually pretty good) flush product but regardless has some info on why it happens on M54's (other threads/guys have talked more about the specific M54 ring design - low pressure rings or something...)

https://blog.bavauto.com/17656/it-ha...king-no-start/

[JPR10]

I came across this video... Does this method hold any merit? Is it something I should try?

Here's the Fix for Cranking but not Start. See this case in particular is an classic example of Piston Ring/Cylinder Wash due to fuel flooding and this can happen to a lot of modern fuel injected vehicles.

What happens is when you cold start the car and specially in colder weather, the ECU dumps more fuel, So if you've started the motor and then moved your car for a bit and then shut down too quickly without letting the motor warm up, lets say within a min or so then the excess fuel gets left in the combustion chamber. And if you dont restart the motor soon enough and leave the car there for some time; in my case which was few days, What will happen is the left over un burnt fuel sitting on the piston will slowly seep down and wash off the fine film of oil that sits between the piston rings and cylinder heads walls and not only lubricates but also makes a seal, a lot of race motors have a system which sprays to make this seal and often a lot of the street cars just rely on splash from the crank to make it while your car runs. Your engine depends on that fine film of motor oil to maintain its compression, without which your compression will drop and therefore it will crank but wont start and may as well cause premature wear, Hence when you have a car sitting for too long, you always put a few drops of oil down the spark plugs. Getting back on the subject, in such a case you will have Fuel, Spark, Timing and everything all right but that wont help because there is little compression.


Now this is the solution for this particular case, I personally know a lot of these cars suffer from Crank and Cam Sensor Problems along with bad fuel pumps, but if they all check out, then this is what you could try and do.


Remove the coil packs and spark plugs, use some electronic parts cleaner/maf cleaner or brake cleaner and let them dry a bit as they are likely soaked in fuel and carbon. Meanwhile put some engine oil or atf fluid down in the spark plug holes into the motor so its sitting on your pistons, use a teaspoon or a oiler squinter or just a syringe whatever works, just around 10 - 20ml of oil is enough. Then disconnect your Fuel Supply (take out the fuel pump relay and fuse) And then crank the car a few times, 5 - 10 seconds in between, do this for a couple of mins.


Then put your spark plugs back in, (clean up the holes where they sit) and reinstall the coil packs and do it all back up. Then crank a few times more, now put your fuel pump relay and fuse back and floor the accelerator / gas pedal while you crank it up, this will in turn cause the ECU in most cars to cut down on the fuel, as in Flood Mode, Do a few cranks like that and then leave it. Then remove your foot off the gas and try to start it as usual, it will hesitate for a min or two, you will see plenty of smoke from your tail pipe which is the oil being burnt, I have heard some scary noises, backfires you name it, then maintain idle till the car warms up to operating temp as in let it idle on its own, once warmed up and all is good, then you can shut the car down. From here it should be as it was.


And in the future remember if you start it up in cold weather and shut the car down immediately, and then dont start it back up for a while, you might run into this problem.

Let me know what you think.

EDIT: It seems like that is what bavauto is suggesting as well...

* Remove the spark plugs and add a small amount of oil to each cylinder. Wait a bit, then cover the spark plug holes with rags and crank the starter. Re-install the spark plugs and crank the engine until it starts (similar to the step below).

* Crank the starter for a few seconds, continuously. After about 10 seconds of cranking, the sound should become a bit more rhythmic with some indication that cylinder compression is building. Take a break with the cranking, we don’t want to destroy the starter by just continuously cranking for minutes at a time as this will get the starter quite hot. Continue the cranking and there should begin to be some indication of some firing. Remember to give the starter (and the battery) a break occasionally. More cranking should eventually get the engine running, perhaps weakly, for a few seconds after cranking. Eventually, the engine will run on its own and clear out all the unburned fuel. After a few minutes of working with it, the engine should be running normally.

[geargrinder]

Yep that's it. Some people leave the ok to soak overnight after the plugs-out turnover. Some of above is overkill (why pull pump fuse AND relay?) But basically it's the procedure. You can be liberal w the oil but not too crazy, don't want to hydrolock the motor..

[JPR10]

Yep that's it. Some people leave the ok to soak overnight after the plugs-out turnover. Some of above is overkill (why pull pump fuse AND relay?) But basically it's the procedure. You can be liberal w the oil but not too crazy, don't want to hydrolock the motor..

Should I be worrying about the SES code for the O2 sensor at this point? Or should I just worry about getting the car started?

[JPR10]

Little update:

Got the car started this morning using this method:

Crank the starter for a few seconds, continuously. After about 10 seconds of cranking, the sound should become a bit more rhythmic with some indication that cylinder compression is building. Take a break with the cranking, we don’t want to destroy the starter by just continuously cranking for minutes at a time as this will get the starter quite hot. Continue the cranking and there should begin to be some indication of some firing. Remember to give the starter (and the battery) a break occasionally. More cranking should eventually get the engine running, perhaps weakly, for a few seconds after cranking. Eventually, the engine will run on its own and clear out all the unburned fuel. After a few minutes of working with it, the engine should be running normally.

CEL remains w/ the same codes. O2 sensor inactivity and fuel mixture, etc

Tons of smoke coming out of the tailpipe:



Engine runs a little rough, and can sometime idle roughly when I give it gas and the RPMs drop back down. Could this be due to the O2 sensor issue?

My next step:
- Replace both upstream O2 sensors

Anything else I should be considering?

[JPR10]

Update: Took my multimeter and set to 200 ohms.

I checked the resistance of both sensors and they are both between 3.2 and 3.5 ohms -- is that under spec for both?

[JPR10]

Another video -- when I got the car running I heard an unusual noise under the hood... It sounds like air escaping, or some sort of air leak... I don't have an EVAP/smoke testing machine... but any ideas of what it might be?

Note: the camera was in that position because that's where the sound was the strongest.. I wasn't necessarily pointed at where the leak might be coming from.