E92 M3 Erratic Idle After Fill-Up

[kscarrol]

elm, any update? Has the update to 240e solved your problem? My car is at the dealer now and they are replacing the what the SA called the fuel tank vent valve which I assume is the same as the fuel tank breather valve that gpitts had replaced...

[NashvegasR]

I'm having this same problem and posted a thread about it. I think I might try to direct the dealer at the fuel purge valve that worked for a few folks.

http://www.realoem.com/bmw/showparts...44&hg=13&fg=15

But -- anyone know -- where on earth is this valve on the car? I assume in the rear. I guess I"m asking if this is a "drop the fuel tank blahblahblah" (not something I would tackle) or is this a "remove the carpet and its right there item" (totally up my alley)

[grantmax]

Originally Posted by Talk2meg00se

240E doesn't fix it.

Correct. 240E is not a fix. I've posted more detailed info in part similar threads.

My car has seen three dealerships and shop foremen. Still tries to choke out after a fill-up. It's almost time to consider this working as intended.

[kscarrol]

Fuel tank breather valve was the cure for me. No rough idle/stalling after fill up since it was replaced...

[5soko]

Ive given up on the fix for my S85, as have many V10 owners.. Be awesome if the real fix is the fuel tank breather, i will be looking into it on my car.

[thekurgan]

Originally Posted by kscarrol

Fuel tank breather valve was the cure for me. No rough idle/stalling after fill up since it was replaced...

What was involved in this replacement if I may ask?

[modkrazy]

I've had a slightly bouncy rev line when cold and right after a fill-up, but never such big dips.

Try a different gas station?

[kscarrol]

Originally Posted by thekurgan

What was involved in this replacement if I may ask?

Good question but I'll have to plead ignorance! Was a warranty repair so dropped it off in the morning and picked up in the afternoon. Sorry!

[thekurgan]

Originally Posted by kscarrol

Good question but I'll have to plead ignorance! Was a warranty repair so dropped it off in the morning and picked up in the afternoon. Sorry!

Nah, no sweat. I'll look at the parts list and I'm betting it's mostly labor.

[kscarrol]

Originally Posted by thekurgan

Nah, no sweat. I'll look at the parts list and I'm betting it's mostly labor.

Probably right! I have the actual service paperwork at my office but my SA printed a summary of my car's records as I went out of warranty in October. It is a brief description but it says "fuel tank vent valve (carbon canister) permanent malfunction". Not sure if that's part of the fuel pump or where it's located. Realoem.com shows an activated carbon filter as part #1 in this diagram...

http://www.realoem.com/bmw/showparts...19&hg=16&fg=10

[thekurgan]

Originally Posted by kscarrol

Probably right! I have the actual service paperwork at my office but my SA printed a summary of my car's records as I went out of warranty in October. It is a brief description but it says "fuel tank vent valve (carbon canister) permanent malfunction". Not sure if that's part of the fuel pump or where it's located. Realoem.com shows an activated carbon filter as part #1 in this diagram...

http://www.realoem.com/bmw/showparts...19&hg=16&fg=10

Yeah that looks like a PITA to R&R. I wonder why they are failing.

[RogEphedra]

I had the same problem as shown in the video in post #20 by kscarrol. However, his did it for a few seconds then leveled-off for a while, then did it again, then leveled-off, etc. Mine was a continuous fluctuation until I drove away. It only stalled once on me in my driveway, but was very close to stalling several times.

Tried to post a .mov video of mine, but couldn't get it to work.

Anyway, as kscarrol and gpitts have said, it appears to be the "fuel tank vent valve" aka "fuel tank breather valve". I took it to the dealer. I showed them 2 videos I took. They were looking for codes even though I told them there was no “service engine soon” light, so no codes stored. After a couple more correspondences with them throughout the day, I could tell they were not going to be able to diagnose it in a timely manner. So I pointed them to this thread, and pushed them in the direction of the fuel tank vent valve. They agreed, and asked for approval to replace. They replaced the fuel tank vent valve, along with the “charcoal canister” aka “activated charcoal filter” to maybe make a little more money. If they tell you the Johnson Rod needs replacing, you say “sure, of course, Johnson Rod”. What the hell do I know? I just want the damn fluctuating idle to stop already. After having these replaced, there have been no more repeats of the erratic fluctuating idle.

So for the guy reading this thread and wondering what the problem is with his car and the erratic fluctuating idle, just like I did, and seeing a bunch of different possibilities brought up, I’m going to say definitively that it is the fuel tank vent valve. Point your mechanic/dealer in this direction. Tell them you really believe it’s the fuel tank vent valve and you want them to replace that.

It’s not the gas, as I tried different gases -- Chevron, Shell, Texaco, always 93 octane, and still had the problem. It’s not the cold weather, although parts seem to really go south when the weather gets cold. But weather isn’t the reason for the fluctuating idle. It’s not waiting for your car to warm up. I let the car warm up plenty, and still had the problem. It’s the fuel tank vent valve.

If you can’t get this fixed immediately, here are some ways to mitigate this:

• Don’t fill up the tank, go to about 7/8 tank.
• Don’t let it sit idle after getting gas.
• If you have to let it sit idle after getting gas (sitting at traffic light), and you are worried about stalling or the embarrassing fluctuating idle sound, shift to neutral and give it a little gas as soon as the idle starts to fluctuate. Just give it the slightest amount of steady gas to keep it from potentially stalling or creating the embarrassing sound. When the light changes, shift back to 1st gear and go.
• If you don’t want to do the above, just shut the car off as soon as the idle starts to fluctuate. When the light turns green, start it back up, shift to 1st gear and go.
• If you don’t want to do any of the above, just know that the car could stall and be prepared to deal with it.

Thanks to kscarrol and gpitts for pointing me in the direction of the fuel tank vent valve.

[gpitts]

Originally Posted by RogEphedra

I had the same problem as shown in the video in post #20 by kscarrol. However, his did it for a few seconds then leveled-off for a while, then did it again, then leveled-off, etc. Mine was a continuous fluctuation until I drove away. It only stalled once on me in my driveway, but was very close to stalling several times.

Tried to post a .mov video of mine, but couldn't get it to work.

Anyway, as kscarrol and gpitts have said, it appears to be the "fuel tank vent valve" aka "fuel tank breather valve". I took it to the dealer. I showed them 2 videos I took. They were looking for codes even though I told them there was no “service engine soon” light, so no codes stored. After a couple more correspondences with them throughout the day, I could tell they were not going to be able to diagnose it in a timely manner. So I pointed them to this thread, and pushed them in the direction of the fuel tank vent valve. They agreed, and asked for approval to replace. They replaced the fuel tank vent valve, along with the “charcoal canister” aka “activated charcoal filter” to maybe make a little more money. If they tell you the Johnson Rod needs replacing, you say “sure, of course, Johnson Rod”. What the hell do I know? I just want the damn fluctuating idle to stop already. After having these replaced, there have been no more repeats of the erratic fluctuating idle.

So for the guy reading this thread and wondering what the problem is with his car and the erratic fluctuating idle, just like I did, and seeing a bunch of different possibilities brought up, I’m going to say definitively that it is the fuel tank vent valve. Point your mechanic/dealer in this direction. Tell them you really believe it’s the fuel tank vent valve and you want them to replace that.

It’s not the gas, as I tried different gases -- Chevron, Shell, Texaco, always 93 octane, and still had the problem. It’s not the cold weather, although parts seem to really go south when the weather gets cold. But weather isn’t the reason for the fluctuating idle. It’s not waiting for your car to warm up. I let the car warm up plenty, and still had the problem. It’s the fuel tank vent valve.

If you can’t get this fixed immediately, here are some ways to mitigate this:

• Don’t fill up the tank, go to about 7/8 tank.
• Don’t let it sit idle after getting gas.
• If you have to let it sit idle after getting gas (sitting at traffic light), and you are worried about stalling or the embarrassing fluctuating idle sound, shift to neutral and give it a little gas as soon as the idle starts to fluctuate. Just give it the slightest amount of steady gas to keep it from potentially stalling or creating the embarrassing sound. When the light changes, shift back to 1st gear and go.
• If you don’t want to do the above, just shut the car off as soon as the idle starts to fluctuate. When the light turns green, start it back up, shift to 1st gear and go.
• If you don’t want to do any of the above, just know that the car could stall and be prepared to deal with it.

Thanks to kscarrol and gpitts for pointing me in the direction of the fuel tank vent valve.

Clearly the Johnson Rod was the solution.

[DMA]

Thanks for this thread I am having the same issues not as drastic drops but it is getting worse.

Will go the route of replacing Fuel Purge Valve seems like an easy DIY based on this thread:
http://www.bimmerfest.com/forums/sho...98&postcount=4

Looks like good price on ECS:http://www.ecstuning.com/Search/13907838281/ES35640/

$70.

Out of Warranty and 3rd Party Warranty deductible would be more than the part. Ill create a DIY and post it up probably will be in the next couple weeks.

[elm3]

Originally Posted by kscarrol

elm, any update? Has the update to 240e solved your problem? My car is at the dealer now and they are replacing the what the SA called the fuel tank vent valve which I assume is the same as the fuel tank breather valve that gpitts had replaced...

So far so good. I haven't had the problem yet. The engine runs differently at start up too when I changed the software. Knocks on wood.

[woody888]

I think I have the same problem.

it's like this??

http://www.m3post.com/forums/showthread.php?t=1069991

[kscarrol]

Yes, looks very similar to what I experienced before having the fuel tank breather valve replaced...

[gpitts]

Originally Posted by woody888

I think I have the same problem.

it's like this??

http://www.m3post.com/forums/showthread.php?t=1069991

Looks like what I experienced as well...

[woody888]

So, It need to replace the fuel tank breather valve will improve this issue?

Forgive me my question, because I went back the dealer many time. They still could not fix my car problem .

My car is still having Erratic Idle...

not only after Fill-Up.

When normal idle it also Erratic Idle

someone tell me, Maybe is fuel tank vent valve or vacuum problem..

[gpitts]

Originally Posted by woody888

So, It need to replace the fuel tank breather valve will improve this issue?

Forgive me my question, because I went back the dealer many time. They still could not fix my car problem .

My car is still having Erratic Idle...

not only after Fill-Up.

When normal idle it also Erratic Idle

someone tell me, Maybe is fuel tank vent valve or vacuum problem..

If you are having issues beyond post-fill-up, then our issues are different. They may root-cause to the same solution, but they may not. Anything beyond this would just be a guess on my part.

[kscarrol]

Originally Posted by gpitts

If you are having issues beyond post-fill-up, then our issues are different. They may root-cause to the same solution, but they may not. Anything beyond this would just be a guess on my part.

I will say that I had this idle mostly after fill-up but on more than one occasion it happened with as little as 1/4 tank of gas. Show the dealer this thread and have them replace the breather valve...

[RogEphedra]

I will say that I had this idle mostly after fill-up but on more than one occasion it happened with as little as 1/4 tank of gas. Show the dealer this thread and have them replace the breather valve...

I agree 100% with kscarrol here, if the dealer can't ID the problem, show this thread to your service advisor and tell him you strongly suspect the breather valve. The idle issue happened at different fuel levels for me too.