Sudden rough idle

[upallnight]

Originally Posted by jfoj

Fuel Trims do not get reset when clearing DTC's. Trouble codes and Freeze Frame data and Emission Readiness Monitors are the only things cleared when DTC's are cleared.

Clearing Adaptation will reset Fuel Trims, but for BMW a BMW specific software, tool or Pro level scan tool with Adaptation Reset capability is required.

Assuming greggo151 checks back in here, he should go ahead and get 3 Logs to see what the O2 sensor health looks like along with Fuel Trims.

It appears his vehicle has had very little maintenance for the STANDARD BMW I6 problems.

au contraire mon ami. not according to this article

BMW and MINI Long-Term and Short-Term Fuel Trim Diagnosis with Launch CReader-VI – Positive Trim | Bavarian Autosport Blog

From the blog/article

"If you do a fault code clearing on the system, this will also clear the long-term fuel-trims. Of course, they will shortly regenerate if the system is still running lean (or perceived to be doing so)."

[jfoj]

Originally Posted by upallnight

au contraire mon ami. not according to this article

BMW and MINI Long-Term and Short-Term Fuel Trim Diagnosis with Launch CReader-VI – Positive Trim | Bavarian Autosport Blog

From the blog/article

"If you do a fault code clearing on the system, this will also clear the long-term fuel-trims. Of course, they will shortly regenerate if the system is still running lean (or perceived to be doing so)."

Well again you are not catching on and understand. Quote some unknown person from a Q & A area on a Parts suppliers website.

I will REPEAT, Fuel Trims are NOT RESET OR CLEARED with DTC's are cleared on the majority of OBDII vehicles.

Clearing Fuel Trims or Adaptations requires something other than a generic OBDII scan tool. Either a manufacturers tool or a Pro level tool that supports specifically clearing Adaptations.

Some think you can disconnect the battery, this was true of OBDI, but not OBDII. OBDII has capacitor memory retention and the battery would need to be disconnected for days or weeks on most models.

I cannot confirm that this is a reliable option, some will say disconnecting the battery and touching the battery cables together for 30+ seconds can clear DTC's and may clear Adaptations on some models, but this is not a reliable option because many of the DME/ECM/ECU are diode protected and the have RAM back up that is not impacted buy this. OBDII specifically requires that codes cannot be cleared by just removing power form the DME/ECM/ECU for short periods of time.

[upallnight]

If you can't reset the LTFT with a DTC erase command, how is it that greggo151 fuel trim scan listed the following:

PID Description Value Units
SAE 0x03 Fuel system 1 status 8
SAE 0x03 Fuel system 2 status 8
SAE 0x04 Calculated load value 23.92 %
SAE 0x05 Engine coolant temperature 177.8 F
SAE 0x06 Short term fuel % trim - Bank 1 0 %
SAE 0x07 Long term fuel % trim - Bank 1 0 %
SAE 0x08 Short term fuel % trim - Bank 2 0 %
SAE 0x09 Long term fuel % trim - Bank 2 0 %

They are close to what a good running engine should be, but he did not have a good running engine. He was getting a MIL light on.

The unknown person is Otto from Bav Auto. I would listen to him more than you. The person that is not catching on is you.

[jfoj]

Originally Posted by upallnight

If you can't reset the LTFT with a DTC erase command, how is it that greggo151 fuel trim scan listed the following:

PID Description Value Units
SAE 0x03 Fuel system 1 status 8
SAE 0x03 Fuel system 2 status 8
SAE 0x04 Calculated load value 23.92 %
SAE 0x05 Engine coolant temperature 177.8 F
SAE 0x06 Short term fuel % trim - Bank 1 0 %
SAE 0x07 Long term fuel % trim - Bank 1 0 %
SAE 0x08 Short term fuel % trim - Bank 2 0 %
SAE 0x09 Long term fuel % trim - Bank 2 0 %

They are close to what a good running engine should be, but he did not have a good running engine. He was getting a MIL light on.

The unknown person is Otto from Bav Auto. I would listen to him more than you. The person that is not catching on is you.

upallnight, you do not get it. If Otto wrote the article he was wrong or not clear on what he was communicating.

Clearing DTC's WILL NOT UNDER ANY CIRCUMSTANCES CLEAR OR RESET FUEL TRIMS. Read, rinse and repeat. Put in the spin cycle if needed.

So what you are posting above from grego151 may or may not have been after any codes were cleared.

BUT, if you PAY ATTENTION and know anything about OBDII, look closely at Fuel System Status 1 & 2, notice they are in State #8. State number 8 is an error state and the engine will default to a non feedback fuel control and will use default fuel and ignition maps. Fuel System Status 8 = Open loop due to system failure.

Oh, BTW, few OBDII tools show, track or Log Fuel System Status, OBDFusion does. And you can specifically thank me for this feature being in current versions of OBDFusion. Few tools, even Pro level tools offer this basic but very important PID.

But also keep this in mind, if gregoo151 did provide another Log it could have very different Fuel Trim info due to a few reasons.

1. Fuel trims are dynamic and Adapt. They change over time and conditions.

2. The shop that greggo151 may have specifically cleared or reset the Adaptations with a BMW specific or Pro level scan tool.

But what you are showing above is clearly when the vehicle was not operating correctly and the System Fuel System status was in Open loop due to system failure.

[upallnight]

Originally Posted by jfoj

upallnight, you do not get it. If Otto wrote the article he was wrong or not clear on what he was communicating.

Clearing DTC's WILL NOT UNDER ANY CIRCUMSTANCES CLEAR OR RESET FUEL TRIMS. Read, rinse and repeat. Put in the spin cycle if needed.

So what you are posting above from grego151 may or may not have been after any codes were cleared.

BUT, if you PAY ATTENTION and know anything about OBDII, look closely at Fuel System Status 1 & 2, notice they are in State #8. State number 8 is an error state and the engine will default to a non feedback fuel control and will use default fuel and ignition maps. Fuel System Status 8 = Open loop due to system failure.

Oh, BTW, few OBDII tools show, track or Log Fuel System Status, OBDFusion does. And you can specifically thank me for this feature being in current versions of OBDFusion. Few tools, even Pro level tools offer this basic but very important PID.

But also keep this in mind, if gregoo151 did provide another Log it could have very different Fuel Trim info due to a few reasons.

1. Fuel trims are dynamic and Adapt. They change over time and conditions.

2. The shop that greggo151 may have specifically cleared or reset the Adaptations with a BMW specific or Pro level scan tool.

But what you are showing above is clearly when the vehicle was not operating correctly and the System Fuel System status was in Open loop due to system failure.

If you know anything about OBD II you would have known that greggo151 cleared the trouble code(s).

This was part of his scan:

This vehicle is not ready for emissions testing.

Reason
MIL On
Stored trouble codes have been detected
Number of incomplete tests exceeds the maximum number allowed
Trouble Code Report


The reason for any incomplete test is because he erased the code(s).

Looks like another one of those time that we agree to disagree. You can believe what you want and I can believe what I want. The people that read this thread can decides who they want to believe.

[jfoj]

Originally Posted by upallnight

If you know anything about OBD II you would have known that greggo151 cleared the trouble code(s).

This was part of his scan:

This vehicle is not ready for emissions testing.

Reason
MIL On
Stored trouble codes have been detected
Number of incomplete tests exceeds the maximum number allowed
Trouble Code Report


The reason for any incomplete test is because he erased the code(s).

Looks like another one of those time that we agree to disagree. You can believe what you want and I can believe what I want. The people that read this thread can decides who they want to believe.

Look I know you type, I had to run one of your good friends off here lately.

I know more about OBDII that you will ever comprehend.

I am working off a tablet a the moment and did not choose to go back through every single post and letter on this thread. I deal with helping and EDUCATING MANY people on MANY threads and forums. The problem is TOO many arm chair mechanics that never lift a finger or confirm anything for themselves.

I am sure greggo151 cleared codes, I am sure greggo151 shop cleared codes. Does not really matter either way, clearing codes DOES NOT RESET FUEL TRIMS. Also when the DME/ECU/ECM is in a Fuel System Status of 8, it is not going to start clearing Readiness Monitors either.

No need do agree to disagree, assuming you do not expect to be spoon fed, you can do you own research and you could even go out and clear codes on your vehicle and you will see that Fuel Trims will not reset. And if there are no codes or a SES/CEL/MIL light you can still force a clear of the DTC's and you will see the Emission Readiness Monitors will start over and you will ALSO see the Fuel Trims will not be zeroed (0) out or reset.

I just do not understand some of the mindsets of some forum members, I also find that some of these mindsets are badly contagious and it is SO SAD to see SO MANY do not understand the basics.

Enjoy your Otto article that is wrong and misleading. Keep convincing yourself you fully understand what you are talking about, it will likely make you feel much better about yourself.

I know what I know and I also will note if I am wrong. I have been doing this FAR too long on FAR too many different makes and models of vehicles and I have spend FAR too many hours researching and reading as well as confirming things in the field. You would be surprised how many documented things are inaccurate, incorrect or just flat out wrong!

[upallnight]

Originally Posted by jfoj

Look I know you type, I had to run one of your good friends off here lately.

I know more about OBDII that you will ever comprehend.

I am working off a tablet a the moment and did not choose to go back through every single post and letter on this thread. I deal with helping and EDUCATING MANY people on MANY threads and forums. The problem is TOO many arm chair mechanics that never lift a finger or confirm anything for themselves.

I am sure greggo151 cleared codes, I am sure greggo151 shop cleared codes. Does not really matter either way, clearing codes DOES NOT RESET FUEL TRIMS. Also when the DME/ECU/ECM is in a Fuel System Status of 8, it is not going to start clearing Readiness Monitors either.

No need do agree to disagree, assuming you do not expect to be spoon fed, you can do you own research and you could even go out and clear codes on your vehicle and you will see that Fuel Trims will not reset. And if there are no codes or a SES/CEL/MIL light you can still force a clear of the DTC's and you will see the Emission Readiness Monitors will start over and you will ALSO see the Fuel Trims will not be zeroed (0) out or reset.

I just do not understand some of the mindsets of some forum members, I also find that some of these mindsets are badly contagious and it is SO SAD to see SO MANY do not understand the basics.

Enjoy your Otto article that is wrong and misleading. Keep convincing yourself you fully understand what you are talking about, it will likely make you feel much better about yourself.

I know what I know and I also will note if I am wrong. I have been doing this FAR too long on FAR too many different makes and models of vehicles and I have spend FAR too many hours researching and reading as well as confirming things in the field. You would be surprised how many documented things are inaccurate, incorrect or just flat out wrong!

Which One???

If Otto is wrong, so must Ross-Tech, a company that produce diagnostic software for European cars.

Fuel Trim Info - Ross-Tech Wiki

From that article:

It is totally normal for both the first and second fields to be something other than zero. In fact, zeros IN BOTH FIELDS indicates that either you just cleared codes (which will reset fuel trim values) or something isn't working properly.

I know you don't care what other people on the internet think, you just know you are always right.

[jfoj]

Originally Posted by upallnight

Which One???

If Otto is wrong, so must Ross-Tech, a company that produce diagnostic software for European cars.

Fuel Trim Info - Ross-Tech Wiki

From that article:

It is totally normal for both the first and second fields to be something other than zero. In fact, zeros IN BOTH FIELDS indicates that either you just cleared codes (which will reset fuel trim values) or something isn't working properly.

I know you don't care what other people on the internet think, you just know you are always right.

I believe you are the one that thinks you are always "right" and the funny part is you have not bothered to get up out of your chair and even verify any of what you read a gospel for yourself!!

Go out, read your vehicles Fuel Trims, clear the codes with a standard OBDII scan tool, then read the Fuel Trims again immediately and see what you find. I think you could answer your own question without help from anyone else.

Oh, but why should anyone do that professional companies NEVER make mistakes.

I know Ross Tech as well, just because they state something does not mean it is 100% correct either. Sometimes these things become a BAD game of telephone.

[bcredliner]

IMO this is an excellent example of how data can complicate, be misleading and even those that are experienced at the data gathering method can have different interpretations of the same information. That's why there is little chance I will get it right. .

Don't interpret this as I am against using diagnostics. I've used diagnostics many many times but only after going through the age old, basic, hands-on troubleshooting did not find the problem or going further required too much wrenching.

This is not intended for those posting but those reading. I mention this because there are so many that are reluctant to work on their X5 because of the electronics and the assumption that because of that one has to have, and be proficient, using diagnostic equipment plus expensive, special tools. Most of the time that is not the case.

Over simplified. engines are still a big air pump. Air in, air out. They still only need adequate air, fuel, compression and spark to run. That means the troubleshooting of the good ol' days is still very applicable. I like solving problems, learning and I hate spending money on someone else when I haven't tried to fix anything that breaks.

As much as it makes sense, I work from the point of air in and work toward air out---air filter, MAF, intake tube, etc. That said, Electronics are sensitive to variations of voltage so it makes sense to be sure the battery and alternator are OK by unlocking the cluster and looking at their real time performance. Remove the air filter and see if it runs better. Check the air intake tube for cracks. Remove and clean the MAF with MAF cleaner. In short bursts, spray some of the MAF cleaner around the engine. That may locate the source of a vacuum leak (idle increases). Use a long screwdriver and put the metal end against each injector and listen to see if the clicking noises are all even and sound very similar. Spray a can of fuel injector/throttle body cleaner as directed. Remove the connection to one pre cat sensor at a time and see if anything changes. Rent a fuel pressure tester from a local auto parts store (rent fee returned when you bring it back in most cases) or use DIY savings as justification to buy one.

For some diagnostics will be easier than the steps to check compression, spark or an injector. If, for whatever reason, one chooses not to go to diagnostics at this point, it is still possible using basic tools to check each cylinder for spark or low compression. To check spark remove power to one coil at a time to see if it runs worse. If that doesn't happen the next check injectors by removing power to one injector at a time.That local auto parts likely also rents a compression checker. Pull each plug and check it and then do the compression check. If problem is not pinpointed at that point I would have a smoke test done at a well recommended Indy that specializes in BMW and uses diagnostics.

If you found the core problem prior to the smoke test you have invested only your time and
about $20. I didn't cover everything and you can change the order of troubleshooting if you want.

And, yes, I might have saved time and that $20 via the diagnostic approach or you can say I worked hard rather than smart or I may not find the problem anyway but I had fun and enjoyed the challenge.

I probably missed something but I think I hit the high points. I thought about adding to check for a potato in your exhaust pipe

FYI, I often pull up Otto's videos, have never been mislead-great source of step by step DIY broken down into non technical language. I'm surprised you didn't know who he was jfoj. He certainly is not unknown and I have found Bavauto to be a great source for quality parts and to get answers to questions I have.

[jfoj]

Originally Posted by bcredliner

FYI, I often pull up Otto's videos, have never been mislead-great source of step by step DIY broken down into non technical language. I'm surprised you didn't know who he was jfoj. He certainly is not unknown and I have found Bavauto to be a great source for quality parts and to get answers to questions I have.

I know about BavAuto and Otto, if there is such a real person. I glanced at the link and there was no clear author listed that I saw, so it is what it is. I prefer to have info with a least an author and date so there is some point of reference and real ownership.

And BTW, I have Launch CreaderVI so I know exactly what the tool is capable of and can do. It cannot clear Adaptations or Fuel Trims.

As for diagnosis, it is really not all that hard. I have helped a lot of folks using data logging for some time and for even the less technical, it has usually been a very good way to identify and resolve problems. It also will allow the user to learn how to use their tool(s) and be self sufficient. You know, "Teach a man to fish".

The data is not confusing, the data is the data. It is when you get narrow minded people that do not listen or want to have a real discussion and learn if something does not make sense or is different than what they assumed.

Its one thing to link or quote info that you have not verified, it is totally a different story when you have training and first hand experience over many years in the field. If you want to link something that is accurate and informative, hopefully you have verified the info is as least somewhat close to correct.

But the other approach is when anyone is dealing with a 10+ year old BMW, you just replace all the plastic and rubber crap under the hood, O2 sensors, fuel pump, fuel filter, spark plugs and valve cover gasket(s) and more often than not you have resolved 95% of the OBVIOUS problems these vehicles have. I would have assumed the E53 crowd was more likely to have searched and done their homework as well as maybe a fair amount of maintenance, but this does not appear to to always the norm here.

Whether it be a E46, E39, E53 or any of the models using the M52/M54 I6, the problems are ALL the same and even if you are not dealing with a BMW it is still pretty much the same, after 10-12 years every vehicle on the road will need a lot of TLC if you expect it to be reliable. Plastic and rubber parts are the first to go, followed by consumables and then move on to other wear items.

Just kind of cracks me up that there are glaring errors in technical documentation from manufacturers, service manuals and so forth and the years after the info is released it is not corrected and bad info keeps getting propagated by the mis-informed or hard headed crowd. It is really sad actually that some people cannot stop for a moment and actually think about something and realize there may actually be an error.

I have run into this same resistance in different forum for many things over the years. Unlike many on the Interwebs, I try to not always take, I try to leave behind helpful and accurate info when I can. I also realize many times I am leaving the info behind for some future user that has not even stumbled upon this forum yet.

BTW, smoke testing can be cheap, quick and easy as well.

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