Yellow emission light 07 X5 53K
 

The last couple of weeks when I start the car it splutters for a few seconds and today I noticed that I have a yellow warning light that I see means there is an emission fault....I checked the gas cap and looked to be secure. Also, I have noticed a drop in power which apparently happens when this warning light comes on...any ideas please?

Thanks

Gary

No need to guess, get an OBDII App and get the codes read and you will know exactly what is going on.

You want OBDFusion, for the iProducts it is $9.99, for Android is is $3.99.

For iProducts you NEED a Wifi adapter, for Android you can use the Bluetooth adapter.

iProducts adapter - http://www.amazon.com/dp/B00WPW6BAE/...BWNPO9BZ&psc=1

Android adapter - http://www.amazon.com/dp/B00WPW6BAE/...BWNPO9BZ&psc=1

So for the basic OBFusion, you are at $30 or less for iProducts and under $20 for Android. Very worth while once you find out what you can do with these Apps.

The is called a CHECK ENGINE LIGHT. or CEL

It is not just 'increased emissions'..it mans there is a fault with the engine that causes the engine to not run properly and THAT may increase emissions.

Tell us what codes are present....go from there.

Codes
 

I took the car to auto zone and they put the code reader on the car...I have two codes - P0171 and P0174 saying something about lean?

The thing is when I start the car it splutters for a few seconds and then settles down to a normal idle speed...about 800K....I took it for a nice drive today and it ran smoothly so looking at some of the things that could have caused the CEL to come on would the car run that well if it was something like a sensor or bad vacuum tube? I did get caught low on gas a couple of weeks ago...down to less than 20 miles..

Thanks

Gary

Assume you have the 3.0l engine?

P0171/P0174 is almost never caused by a bad sensor, it is more often than not caused by intake air leaks. Contributors can be Intake Boots, CCV and Hoses, DISA, Fuel Pump.

You NEED to buy OBDFusion so you can provide warm idle Fuel Trim and Freeze Frame data. This is where to start to get an idea as to what is going on for sure.

CEL
 

OK...so I took it to my dealer and they ran all the diagnostics and everything is working correctly...no leaks etc. they cleared the codes but about 100 miles later they came back again but the problem at startup is not as bad since I put premium gas in...the dealer thinks it may have been some gas that more than 10% Ethanol...

I cleared to the codes again today so I'll see if they come back.

What engine do you have?

Still recommend you get OBDFusion, it can tell you a lot about what is going on. Just because there is NO SES/CEL/MIL does not mean everything is operating properly with the engine.

I doubt the problem was with bad fuel, usually you have more obvious problems then Lean codes.

If you own or drive a 1996 or newer vehicle, you NEED your own OBDII tool and for under $20 it is a no brainer!

I highly doubt they did adequate testing, unless you spend $450 and had them do a smoke test.

More likely they screwed you over for a quickie $149 scan and check, found nothing 'active' and gave it back to you.

Then, over time, the leak drove the long term fuel trims to the limit and ding- CEL

CEL
 

They told me they did a smoke test and found nothing...fortunately the dealer is my next door neighbor so he did the analysis for free since he had the card for another issue - cracked expansion tank. Maybe I'll take the advice and get the software...what's really weird is the car drives so good...took it to Chicago and back (300 miles) and ran as smooth as silk except when you start it.

I cannot seem to get an answer about what engine you have in your vehicle, so I am going to assume at 3.0 I6 gasoline engine based on the cracked expansion tank comment. But it would be much easier if I did not need to guess and you could answer the question.

The 3.0 has all sorts of problem areas that cause misfires on cold start that a smoke test will not reveal if performed when the engine is warm and also will not find if the crankcase is not smoke tested as well.

Smoke testing is one method to find air leaks, but often the cold start problems require the vehicle to be stone cold after sitting over night, you cannot even start the vehicle to move it into a service bay, the smoke tester needs to be brought to the car.

Plastics and aluminum expand so quickly that even a few seconds running some leaks can seal up and be elusive.

Having your own OBDII tool can give you and us a lot of insight as to what is happening. It will likely pay for itself the first time you use it.

CEL
 

Sorry...yes I have the 3.0 Gas engine...and I just took your advice and purchased the OBDFusion app and the wifi connector from amazon as the the light came back on again this morning. The problem is not as bad as it was but obviously the engine is compensating for something not working right.

Thanks for your responses. The OBDFusion app looks pretty cool so looking forward to using it and finding the problem.

Gary

I do not know the N52 as well as I know the M54, but I can tell you if the N52 is as close to the M54 as I think it may be, the majority of the cold start/Lean problems are due to vacuum leaks.

The DISA o-ring seal being one of the main sources at lower mileage.

I think the N52 actually has 2 DISA valves to make things even more challenging. Also I do not think anyone has started to look at non BMW solutions for the DISA primary seal like on the M54.

You might be into a smoke test once you figure out what the codes are.

Here is a simple smoke test option -

https://www.youtube.com/watch?v=AsgB9eBl58I

There is no where near the amount of diy stuff out there for the n52, n55 etc as there is for the m54. I'm curious as to whether aftermarket parts will ever appear in the same quantities. Bearings, pumps and the like.

I do not know enough about the N52 numbers, it seems that the M54 was a very popular and long running powertrain option, then the N52 showed up for a short period of time be direct injection and turbo charging became more popular.

I expect some aftermarket support, however, it may not be to the level that the M54 is supported.

This is why I look at a number of factors when I consider purchasing vehicles. I like to have "proven" and supported powertrains. I recommended a number of my friends to avoid the early turbo I6 for a number of reasons as I know the NA I6 was pretty well tired and tested.

obdfusion
 

So i have the adapter and software...what do i need to be looking for to see what is causing the lean codes please?

Thanks

Gary

Ok, saw your message, just so everyone can follow along you had P0171/P0174 Lean codes. Both Bank's Lean.

The BMW I6 engines are famous for vacuum leaks, but I can say I know the the M52/N54 engines like the back of my hand. The N52, I do not have much experience with, but like anything the problems are all pretty much the same, it is just pinpointing the exact cause on the specific engine.

So the first thing you need to do is to NOT clear the codes until you get ALL of the Freeze Frame data. On OBDFusion there may be 2-3 pages of Freeze Frame data that you usually access by swiping sideways or vertically on the screen. Make sure you forward that info to your email account or better yet set up a DropBox Free account and then upload the info to DropBox so it can easily be shared here in the forum. Will get into this in more detail later. One IMPORTANT thing is DO NOT download and install the DropBox software on your computer, it is NOT NEEDED and it will cause some issues if you do not manage it. When you go to install the DropBox software on your computer, once you enter your email address and password and it prompts you to download the software on your computer, just hit the BACK browser arrow and you will then be in your DropBox account.

So on to the OBDFusion App, you really need to spend about 20 minutes playing with it and finding your way around. Because these are Apps and the smart phones have few buttons, there are sometimes Menu buttons on screen or you have to touch and hold for a Menu to pop up.

You need to spend 20-30 minutes playing with it. The problem with ALL smart phone/tablet Apps is they only have 1 physical button, a few soft buttons and a LOT of hidden menus from pressing and holding on the screen.

OBDFusion is FAR more intuitive than other Apps.

First change the MAF reading from Pounds/Min to Grams/Sec, stupid EASY.

Settings, Units, Airflow, choose g/s.

Temp sometimes can be more useful in C vs F, but no so critical.

Settings, Log Setup then set the following:

Logging Enabled - checked

Logging Trigger - choose Trigger at a fixed sample time

Sample Time - choose 1000 msec

Log GPS Items - suggest you unselect it as to not advertise where you live

Select Items to Log - This varies a bit for each car. But here is a list I like to see:

Fuel - do not check any of these 3 items

SAE PID's:

Fuel system 1 status
Fuel system 2 status
Calculated load value
Engine coolant temperature
Short term fuel % trim - Bank 1
Long term fuel % trim - Bank 1
Short term fuel % trim - Bank 2
Long term fuel % trim - Bank 2
Engine RPM
Vehicle speed
Ignition timing advance for #1 cylinder
Intake air temperature
Mass air flow rate
O2 Voltage (Bank 1, Sensor 1) - not all cars have this
O2 Voltage (Bank 1, Sensor 2) - not all cars have this
O2 Voltage (Bank 2, Sensor 1)
O2 Voltage (Bank 2, Sensor 2)
O2 sensor Voltage wide range (Bank 1, Sensor 1) - not all cars have this
O2 sensor Voltage wide range (Bank 2, Sensor 1) - not all cars have this
Input Voltage read by the scan tool

Before you clear codes, get the Freeze Frame data and email or save the screen shot if this is an option. Freeze Frame data saves about 20+ questions as to what is going on.

One the App is started and connected to the vehicle, it ALWAYS Logs.

The Log files can be found under the Logs, Files tab.

WARNING do not waste any time trying to Graph on the App. All Apps and most standalone tools really SUX at Graphing, even the Pro level tools that are upward of $2k. You can play with it, but DO NOT bother posting any of the Graphs they are nothing but confusing and lack any real depth or information that can be helpful.

Under Diagnostics, you find Trouble Codes, Freeze Frame Info, PID Values and Report which you may need to swipe to the right to find while touching the Tabs listed. Depending on the size and layout of your phone Report may or may not be a visible tab. Sometimes it is just easier to rotate the phone to Landscape mode.

Make sure when you run a report the engine is running, this way I can at least see more data.

You can also perform Screen Shots or Grabs. On Android you hold the Power and Volume Down button until you hear the picture sound. On iProducts you You can capture the screen on your device by using the Sleep/Wake and Home buttons. You can find the screenshot in your Photos app.

You need to drive the vehicle until the SES/CEL/MIL comes on again and get the Freeze Frame data. Also Log the mileage and codes you get as this may be useful at a later date.

How many miles are on the vehicle now?

You may also have to get the parts for a smoke test to find intake or crankcase air leaks depending on what we find.

Fuel Trim values will be our friend here, this is what will help to understand what may be going on. I will need Logs and/or Fuel Trim values at warm idle and steady highway cruise. This is where Logging is helpful because the tool gathers and stores the data, you do not even need to look at it.

Do not be surprised if the CCV and hoses might be a problem or the intake boots.

I am sure I will give you more assignments once you figure out the Logging.

OBDfusion
 

Thanks for the detailed response...I can see why you were suggesting getting this app....so before I got your email I was playing around with the app and cleared the codes but I'm sure they will come back as they did before. I have changed the settings on the app so do you want me to wait until the code comes back or log the data now? I thought I could log it now because it will still tell us what is going on?

Thanks for your help...

Gary

Logs
 

OK..here are 3 log files....

https://www.amazon.com/clouddrive/sh...hare_link_copy

Thanks

Gary

I need another Warm Idle Log or you uploaded the wrong Log as this was before you chose the PID's to Log.

Only quickly glanced at the Log, but WOW, the LTFT are sky high, even at highway cruise. I would expect the codes to be back soon if you can actually drive the vehicle.

In short, when the LTFT are high to the Positive side at highway cruise, usually the problem is an under reporting MAF or a soft fail/weak fuel pump.

But before go down this road I need some history about the vehicle.

Have you refilled the fuel tank since you were at the dealer that claimed you had bad fuel?

What is the history on the MAF? Do you know if it original or if is was ever replaced?

Has any work been performed that may have required the O2 sensors to be disconnected?

Can you make sure you add the Wideband O2 sensors to the Logging?

If you look at the list of things to Log they may be listed as either Wideband O2 sensors or Lambda sensors. Usually they will have green data or values on the PID's that the engine supports.

It may be time for a Smoke Test?

But again, I want to re-read your comments from the beginning of the thread.

Lean codes
 

Yes...I have put 2 tanks of premium fuel in since the dealer suggested it could be bad fuel and the car has been running great and even the start up is not as bad as it was in the very beginning. I'll check the settings on the phone and send another log.

As far as I know no mods have been made to the MAF...I purchased the car in the summer from Fields BMW in Chicago and it was a car they had sold as new and did all of the servicing. It had 50K miles and now has 55,500K...dod you need the exact mileage?

I know the dealer tested the fuel pump pressure and told me everything was OK there...not sure about the O2 sensors being disconnected...he told me he tested those too.

What would be causing the LTFT to be so high?

I'll post a new log later.

Thanks for your help

Thanks for the reply and answers.

I just needed to know some of the vehicle history to get an idea as to what I am dealing with. The problem about being an "Internet" mechanic is I have to make a lot of assumptions and/or sometimes I have to try to rule out a lot of things. Figure out what is right to find out what is wrong.

I will wait until you can get the additional warm idle Log with hopefully the Pre-Cat Wideband O2 sensors.

There is something CLEARLY wrong here. LTFT are off by 25%. This could be a few things. Either the engine is really running Lean and the fuel trims are high based on a Lean problem or there is a false reading and the engine thinks it is running Lean.

What does the fuel mileage appear to be, does it appear to be close to what you may expect or do you think if it not as good as expected.

Again, I need to look over the data again before I make any suggestions.

I do not think this is a vacuum leak at first take because the Fuel Trims are off even at highway cruise and idle by about the same amount. You also mentioned that a smoke test was already performed as well with no obvious leaks identified.

Lean codes
 

Thanks again for responses...I'm getting ready to go for another test run to gather the additional info you need

Regarding MPG...I only do short runs to work etc. and my average is 21mpg which has been constant.

And yes, the garage did do a smoke test and didn't find anything but I can't say if it was done when cold...I'll find out.

Thanks

Gary

Lean codes
 

Here's the latest log:

https://www.amazon.com/clouddrive/sh...hare_link_copy

Let me know what you think please.

Thanks

Gary

Your case is a bit tricky, but I think I have an idea. I may or may not be correct and you may or may not choose to get a 2nd opinion.

I am newer on this Forum, but I have been around BMW's, BMW and other forums for quite a while and have helped MANY members actually solve problem. Even problems Dealers and Independents failed to resolve quickly and effectively.

Reviewing the Logs, what stands WAY out is the Long Term Fuel Trims are about maxed out. Typically most BMW's max out the LTFT at around 27%. You vehicle is operating in the 15%-25% with a few higher spikes. Based on these high LTFT values, I would expect your vehicle to quickly and consistently trigger P0171/P0174 Lean codes as soon as the Emission Readiness Monitors start to change to Clear/Ready/Pass.

I do not have much baseline data on the N52 engines, but given these are effectively the same displacement as the M54 engines, I would expect about the same MAF reading at idle.

I am highly suspect of your current MAF readings, they are about 1 g/s too low at idle. What I think is the MAF is under reporting the airflow, thereby no commanding the DME to provide the proper amount of fuel so then the the LTFT must compensate. Most sensors and things degrade over time and rarely, if at all, will a degraded sensor "over report", they typically "under report".

One of the MAJOR problems these days are Asian counterfeit sensors on the market that look legitimate, however, the do not function properly. Anyone can copy and cast plastic and make labels, but the guts of the sensor are IMPORTANT and cannot vary by more than 1-2% at most, otherwise there will be problems.

You typicaly MAF reading at idle is around 3.2 g/s, my typical 3.0l M54 that I have good baselines on are around 4.2 g/s at idle which is around a 25% difference just at idle which is about how far off the LTFT is. You can attempt to clean the MAF, however, I find this does usually do much for a MAF. Make sure your air filter is clean and hopefully the smoke test was performed at the input of the MAF opening to rule out any obvious air leaks.

If you source a MAF, suggest you use BMW Parts Catalog to look up the correct part number. Then plug the part number into this tool to find the best price from a reliable vendor - BMW Part Number Price Comparison for Windows & Mac

You do not have to purchase from an online BMW dealer, however, you can. I have found historically that OEMBimmerparts.com tends to have quality products and some of the best pricing.

My take is even if I am wrong, you save a lot of money for shop labor for both diagnosis and parts mark up. I always recommend people keep their old MAF. Once you inspect the MAF's side by side you may find out this is an aftermarket of Asian counterfeit.

I have attached just one graph so you can see how the LTFT vs RPM looks.

Lean codes
 

I think your deduction could be correct. All the data and symptoms seem to lead in the MAF direction so I'll source a replacement and let you know

Thanks

Gary

I hope I have hit the nail on the head. Sometimes I can be wrong, sometimes the problems can be very unusual and rather off the wall and very hard to identify.

But if this turns out to be wrong, then hopefully you can rule out the MAF as a problem and then move forward. But I think if you watch the g/s MAF reading at idle and compare them with the new MAF you should be able to tell almost immediately there is a difference.

The LTFT may take as long as a week to shift or "Adapt" back in the proper direction once the new MAF is installed. So even if you start to see 4+ g/s MAF readings at idle but the LTFT are still high, be patient and watch for them to start to drift back closer to 0%. Most of these engines typically run around +2% to +3% LTFT at idle, they rarely ever settle on 0%.

I hope I am correct in your case. Again, without being able to put hands on the vehicle an try a few things it is often hard to get to the bottom of some problems.

Worst case end up with a shelf spare MAF or you could sell it though the classified section or Craigslist. But even if you spend money on the MAF and this is not the correct diagnosis, you may still be much further ahead financially then if you took the vehicle to a shop and paid for "Fuel Injector Service", throttle and idle control valve cleaning, a "computer diagnosis" for 1+ hour of labor and so forth. Your "computer diagnosis" cost less than $30 and is probably far superior than what you would have paid for at any shop.

Keep us informed. Hopefully others can learn from this case whether the outcome is good or bad. As I always remind people, just because there are no lights on the dash does not mean everything is operating 100%.

Lean codes
 

Well so far so good...no codes and the car is running as normal. I talked to my dealer about replacing the MAF and he advised waiting until the CEL comes on again.

Gary

I am sure jfoj knows this but as MAFs age they become contaminated with oil, soot, crap...they may have a self cleaning cycle, but eventually they build up a layer of material over the sensor-and this acts as an insulator

since a maf is a type of hot wire anemometer, insulation on the sensor will make the sensor report lower air flow. or more air is entering than the maf thinks- In other words the engine gets lean (or tries to, the fuel trims get driven up to counter this- but eventually it hits the limit and CEL/code).

A quickie diagnosis can be to clean the maf with maf cleaner- if it HELPS, you likely have a maf issue. Replace the maf. Although since the oxide layer left after repeated self cleaning will not be dissolved with solvent, it is not a complete or permanent fix.

This is a major failure mode with those POS K&N oiled filters.

An interesting wiki: Mass air flow - S4wiki

CEL came on again
 

OK so just as everything was running better the CEL came on tonight...I'll hook up the OBDFusion and collect the info and see what it says.

Gary

Codes and Freeze Frame data is what is needed.

Make sure you get all pages of the Freeze Frame data.

You can also use the Report feature while the engine is running as well.

Under Diagnostics choose Report.

Then you can Save and Share/Upload the Report in addition to getting Codes and Freeze Frame data.

Data
 

OK...here is a link to the file:

https://www.amazon.com/clouddrive/sh...hare_link_copy

How do I get the freeze frame data? I can see it on the iPhone but don't see a way to send it?

Thanks

I am not an iPhone user, sometimes there are hidden menus where you touch and hold on the screen and another menu will pop?

You can do a screen grab as well.

You can capture the screen on your iOS device using the Sleep/Wake and Home buttons. Press and hold the Sleep/Wake button on the top or side of your iPhone, iPad, or iPod touch, then immediately press and release the Home button. You can find the screenshot in your Photos app.

I think if you run a Report it will gather the Freeze Frame info as well.

Of you do not see the Report tab, rotate the phone to landscape and you will see it on the far right under the Diagnostic section.

Also post all the Codes as well.

Initial look at the Log is the LTFT is sky high. Lean condition or possibly bad misfiring causing what appears to be a Lean condition.

Really need to see the codes, Freeze Frame and 4 minute warm idle Log as well.

Freeze Frame data
 

OK...here is a link to the freeze frame data which also also the log from this morning...P0171 and P0174 are the codes again.

https://www.amazon.com/clouddrive/sh...hare_link_copy

Thanks

Gary

Typical Lean codes.

Most likely an intake air leak or MAF related. Intake air leak can easily be ruled out by Smoke Testing.

You can do this with about $15 in parts.

Cheap fluid transfer pump from the local Auto Parts store. A few rubber gloves and rubber bands and a few cheap cigars.

https://www.youtube.com/watch?v=AsgB9eBl58I

Best to rule out the simple and obvious problems before dropping bigger money on parts.

Still would best to also see a 4 minute warm idle Log again.

The problem here is if there is an intake air leak, it will cause the MAF to under report because air will be bypassing the MAF.

It might be something as simple as an intake boot that was not installed properly and has pulled off. Not sure if the intake boot is like the M54 engines where the small tube cracks.

I think this may be like what your engine has?

Genuine BMW | Intake Boot/Air Duct (E70 X5, E71 X6) - BimmSport

The smaller tube typically connects to the ICV, assume this may be the same for your engine?

Idle log
 

Here's a link to the idle log...

https://www.amazon.com/clouddrive/sh...hare_link_copy

Thanks

Gary

My best guess is an intake air leak of some sort at this point based on the latest warm idle graph.

Suggest a smoke test to rule out any intake air leaks before proceeding to a MAF.

If there are no intake air leaks, then I might point the finger at the MAF.

But as I mentioned, previously, intake air leaks can and will bypass the MAF so the MAF reading can be lower than expected.

New MAF
 

OK...my dealer got me a new MAF to try before buying...if it still throws codes he can send it back for a refund....attached is a link to the log after the MAF was installed...

https://www.amazon.com/clouddrive/sh...hare_link_copy

Anything stick out?

Thanks

Gary

Still shows as Lean, but how far have you driving on the loaner MAF?

No CEL yet
 

OK...so 500 miles with the new MAF Sensor and no CEL. I'll post a new log now that the MAF is settled in for analysis.

Thanks

Gary

I will look at it once you get it posted.

Latest results
 

Here's a link to the log from this morning

https://www.amazon.com/clouddrive/sh...hare_link_copy

Still running good with no CEL:)

Still not looking so good. Long Term Fuel Trim is still high. Lean codes will probably be triggered soon.

You need to change the MAF reading from lb/min to g/s. Very easy, go to Settings, Units, Airflow and change from lb/min to g/s.

I would like to see a 4 minute warm idle Log in neutral.

I would also like to see a 4 minute steady cruise in the 45-60 MPH range. Straight, flat road would be best and try to hold speed or use cruise control.

Something is still not right.

The engine is running good at this point?

Log
 

OK...I'll get some more data over the weekend....the car is running good and MPG is right around 21 which is typical since most of what I do is around town.

I haven't had to pay for the MAF sensor yet

Thanks...and Merry Christmas

new log
 

OK...so here is the test drive from this morning....I've got about 5 minutes of steady 56MPH and then at the end 4 mins of idle...let me know your thoughts. Looking at some other guides it seems that anything that is more then 10 combined (STFT and LTFT) is not good...but the light still hasn't come on?

Thanks for your insights

Gary

https://www.amazon.com/clouddrive/sh...hare_link_copy

Gary,

Sorry for the delay. I looked over the Log files briefly but I need to think about this a bit more. Something is still not right.

I need to go back and really compare if the MAF made any significant difference.

Fuel Trims are still higher than they should be, surprised you have not triggered any Lean codes yet, but not sure how much you have been driving and what kind of driving you have been doing.

Not sure if the Adapations are slow to react on this platform or you may have just too few miles so far.

You may want to drive the vehicle then leave it idling for about 15 minutes before grabbing another 2-4 minutes of idle Logs.

This is the N52 I6? I do not have enough hands on with this motor as compared to the M52/M54 I6 so there may be something I am not familiar with on this engine causing the Lean codes. As I recall this engine also has 2 DISA's? I have no idea if the the DISA configuration on this engine is as problematic as the M52/M54.

I am tied up the rest of the day, so I may need to get back on these Logs tomorrow.

Are we sure the headings are correct? On the short and long term trims?

If it is from a .CSV file it should be correct. Easy enough to verify.