Rough idle, no power loss, lean on acceleration

[bmwlover0725]

I decided to make this a bit more simple because my post was long yesterday and I doubt anyone wanted to read it.

I received code P2096 yesterday while trying to do my drive cycle. This morning I got P114D. The data on my scanner reads the following:

With engine OFF:

02S12 V: 0.435
02S22 V: 0.435
02S11 mA: 0.499
02S21 mA: 0.499

After letting it sit for a few minutes, O2S11 hits 255.xxx mA, but O2S21 stays at .499 until I turn on the vehicle. The first one always goes way up and down, but while the second one sometimes hits 255.xxx, it drops way below and likes to sit at 10.xxx to 13.xxx - the same goes for the same bank on the ones measured in voltage. One measures around .8 and fluctuates a bit while the other one stays below .09

The car has a rough idle, but from 1-2k revs fine and the numbers seem okay. At 2-3.5k it goes way lean on bank 2 again and vibrates the entire vehicle.

I know this is probably typed like I've never seen an engine before, but I'm trying to make it as simple as possible here. I'm drained from two days of research and no solution.

I did get two front O2 sensors used locally for 20 bucks each that look to be in good shape, but I haven't tried them yet. I hope this isn't a cat issue. MAF looked clean when I had it out but I'll shoot some MAF spray in it just to be sure. I also haven't tackled my secondary air on bank one which I'm wondering about it being related to this.

And of course... My wife is on the verge of murdering me

[thekurgan]

S65 has no MAF, so what are you spraying?

[javarithms]

Originally Posted by thekurgan

S65 has no MAF, so what are you spraying?

OP good luck, hopefully you'll get her up and running again!

[bmwlover0725]

I thought the air sensor attached to the secondary air hose from the manifold was considered to be a MAF

[thekurgan]

Originally Posted by bmwlover0725

I thought the air sensor attached to the secondary air hose from the manifold was considered to be a MAF

Aside from some additional vibration for a minute or so, SAP shouldn't cause your symptoms.

[tbrown1985]

Have you checked your temp to make sure you dont have a bad thermostat?

[bmwlover0725]

Originally Posted by tbrown1985

Have you checked your temp to make sure you dont have a bad thermostat?

Temp sits right around 180 driving. Close to 190 at idle. That should be normal, shouldn't it?

An update on this as well. Had it checked on an Autologic yesterday. Pulled 277D and 27C6. 27C6 seems to be a bank 1 fuel trim issue. 27B0 for secondary air is of course still coming up.

Here is what I've done so far

Checked spark plugs - they're like new.
Changed upstream O2 sensors.

It sounds like there is a leak from under the vehicle, but I couldn't find it on the lift. It sounds like a leak when you put your head next to the cats, but I can't figure out where because there doesn't seem to be anything coming out.

The fuel trim seems to even out while driving, but is terribly lean on bank 1 at idle. I'm also getting mixed codes for 277D between catalyst and battery voltage. Different sites are telling me different things as to what the code indicates. I know batteries can have issues with electrical in these cars, but an emissions issue?

What is my next step? Replace the cats? I know that an exhaust leak could cause this on bank 1, but cats don't cause that bank to run lean as far as I know.

[thekurgan]

Fuel pressure might be an issue as well, although I believe there is a sensor for that as well. There is also a tank purge thing many have had issues with as well. A bottle or two of techron concentrate wouldn't hurt before you go spending gobs of dough.

[bmwlover0725]

Originally Posted by thekurgan

Fuel pressure might be an issue as well, although I believe there is a sensor for that as well. There is also a tank purge thing many have had issues with as well. A bottle or two of techron concentrate wouldn't hurt before you go spending gobs of dough.

Tried two of the small bottles which equals more than one big bottle

[thekurgan]

How old is your battery? Post cat O2? I'm drawing a blank without searching somewhere. You might want to PM one of the tuners here to see if they would have a clue.

[bmwlover0725]

Originally Posted by thekurgan

How old is your battery? Post cat O2? I'm drawing a blank without searching somewhere. You might want to PM one of the tuners here to see if they would have a clue.

Checked battery voltage and it seems fine. Don't know battery date. However, I left this in the hands of a shop because I just do t have time right now and I don't want to toss parts at it.

I left it with Cantech Automotive in Syracuse. They're experts with this car from what I hear. I will find out more tomorrow or Monday, but after the hour drive there I have a pretty good idea of what it may be...

Here is my theory until they call: The exhaust leak is getting louder. I think it is the cat to be honest. I couldn't actually feel the top part of the converter on the lift because the car was at operating temp still running and way too hot obviously. That leak is coming from bank one and is a more defined hissing noise now. Bank 2 is running rich so I would have to assume that IF there is a leak in the cat, that the reason the O2 is reading fine up top is because the leak is after and because of the lower leak, the two sensors are communicating and creating a rich condition for that bank to compensate for the lean detection. Bank 1 has a condition which I think may be created because of an issue with the secondary air because it's running lean. That side was noted as a rich condition has leaned out according to my data while the other side with the lean condition is now running rich as a result of running lean for too long.

Perhaps that is completely opposite or not even close, but that is what I'm getting.

The LAST thing which may trump that completely is that the vehicle has an easy to hear whistle while on the gas at highway speeds coming from the engine bay. The description of the purge valve problem matches that, the running issues, AND the lean/rich conditions perfectly. Regardless, it has an annoying leak anyway and assuming that this will be done quickly and inspected, I will swallow my pride and have my first job done by a shop assuming the bill isn't going to be outrageous for what the job entails. Kills me to have to have someone else do it, but I need this fixed and I HATE emissions issues.

[tbrown1985]

I was going to mention the purge valve. My m5 had that problem but it would only act up after filling up with gas, but it did have the same symptoms you are describing. The rear O2's dont do anything but monitor the cats, so they wont effect mixture. Curious to hear what fixes it. Let us know.

[bmwlover0725]

Originally Posted by tbrown1985

I was going to mention the purge valve. My m5 had that problem but it would only act up after filling up with gas, but it did have the same symptoms you are describing. The rear O2's dont do anything but monitor the cats, so they wont effect mixture. Curious to hear what fixes it. Let us know.

Haha I swear if this thing had the same emissions AND throttle issues that your M5 did I'm going to die. I called them today. They're taking it into the shop in a bit. I should know today. Kind of wishing I just replaced the damn thing while I was in there seeing how it could probably use it anyway and it costs less than an hour of labor for the part. Oh well. My guess is the secondary air check valve and that will be the issues. Probably the exhaust leak too.

[tbrown1985]

Now you know why the M5 is gone. Wife was sick of me spending all the time in the garage under it. And frankly, I was getting tired of it too.

[bmwlover0725]

Originally Posted by tbrown1985

Now you know why the M5 is gone. Wife was sick of me spending all the time in the garage under it. And frankly, I was getting tired of it too.

Yeah I hear ya. I love this car, but I'm very annoyed at the issues. We did buy it as-is expecting them though so I can't really complain.

I should be hearing from the Cantech today. They have an amazing reputation, but I'm a bit disappointed at their customer service. I called yesterday three hours after they pulled it in and he said they didn't complete the two hours I authorized them for. I know how these places work so I get it, but I was frustrated at having NO result, as they "don't like to bother technicians until they come to them." ...What the hell is that?

[bmwlover0725]

UPDATE!!!

I picked the car up from Cantech today. They said I needed a new cat because bank 2 was having issues. Of course I wasn't about to pay 5500 for an OEM cat + labor and NYS inspection. I took it home with the check engine light still on and decided to check it tonight. Since they swapped rear O2's according to a TSB and reset it - all of the monitors except secondary air have set which is good enough for me. Both banks are reading the same as each other as well, so I doubt it is the cat.

Both O2's now switch as necessary and there isn't any major lean condition that I can tell on one vs. the other. I CANNOT get it inspected yet because the SES is activated for P0191 for the fuel pressure sensor. I haven't tested fuel pressure yet, but my scanner is reading about 400 kpag or slightly below at idle and WOT quick up to 3k makes it read about 620.

I'm not sure if this is within spec, but I think I can now narrow this down to a fuel delivery issue since the readings are now consistent and no longer abnormal on one side vs. the other.

Does anyone know what my fuel pressure should read in bar, kpa, or psi? I know this could be an injector issue as well, but since that sensor is reading strange before it actually hits the rail, I'm wondering if the sensor itself, fuel pump, or fuel filter (if any) needs replacing.

Is there a fuel filter? I'm going to see if I can find a pressure sensor locally tomorrow and hope that by starting with that since it's the cheapest part, that it will work. If anyone has thoughts, please let me know. This is becoming insanely urgent, as I desperately need it done before the end of the month

[thekurgan]

The sensor is cheap and an easy-to-replace item. I'm betting the fuel filter is in-tank. There have been many folks here with the fuel sensor code and most were just sensors that needed replacement iirc.


http://www.m3post.com/forums/showthr...ighlight=P0191

[bmwlover0725]

Originally Posted by thekurgan

The sensor is cheap and an easy-to-replace item. I'm betting the fuel filter is in-tank. There have been many folks here with the fuel sensor code and most were just sensors that needed replacement iirc.


http://www.m3post.com/forums/showthr...ighlight=P0191

That was the thread I saw that led me to my conclusion other than the code itself. I have the luxury of auto part international delivering the OE part to my showroom today so it should be quick. I don't want to reset monitors unless I have to. Would this go away after a couple cold starts if the sensor solves my issue? If that does it then I'm good to go for inspection finally!

[bmwlover0725]

Had to reset it. Car ran rough despite the new sensor, BUT after clearing the code it seems much better. I wouldn't say flawless, but everything is reading about where it should and catalyst monitor is set. Bank one is still slightly lean which I'm starting to think is a cat issue with the slightly rough running, but everything seems to have normalized and all monitors have set except O2, EVAP, and secondary air which I'm trying to avoid because there is still an issue with it. Any advice on EVAP and O2? I haven't done a cold start yet, but my first cold start may be my only chance if the secondary air adds a pending code. Next try after that will throw the light. I'm going to order a check valve because I'm assuming that it is my issue. Either way, I'm hoping that will be after I get the inspection taken care of

[bmwlover0725]

Final update. Fuel sensor fixed the lean issue and I did a full proper drive cycle before work today. Everything set and only a pending code for secondary air popped up, no SES though. I'll do that one next week and replace the valve.

Bottom line: car has passed inspection and a HUGE weight is off my shoulders. Paid 17400 for it. Put under 1k into it. Fixed. Thank you guys so much!

[tony093]

Paid 17400 for it. Put under 1k into it. Fixed. Thank you guys so much![/QUOTE]

that is a steal....what's the mileage again?

[bmwlover0725]

Originally Posted by tony093

Paid 17400 for it. Put under 1k into it. Fixed. Thank you guys so much!

that is a steal....what's the mileage again?[/QUOTE]

Outrageous lol. 135k. Has a rebuilt motor though at least. Somebody just decided to attach all the old electrical parts and not finish the job. Still about 10k under book though so I won't complain. Plus I financed it at 2.39 for 72 months. On that mileage for that term, it's pretty good. That's the luxury of being an F&I manager lol