Idol rough after filling up gas tank

Past few gas trips car has a fluctuating erratic idle right after running from the fill up. This only happens while the car is stopped and full, idle bounces up and down but engine doesn't stall. After 5 minutes of driving it does not happen until the next tank fill. No power issues, 2013 DCT 36k miles. Only use 93 octane and iv tried different gas stations but still happens only after tank is filled for few minutes after. Anyone else have this problem?

Ringtaxi wrote

Past few gas trips car has a fluctuating erratic idle right after running from the fill up. This only happens while the car is stopped and full, idle bounces up and down but engine doesn't stall. After 5 minutes of driving it does not happen until the next tank fill. No power issues, 2013 DCT 36k miles. Only use 93 octane and iv tried different gas stations but still happens only after tank is filled for few minutes after. Anyone else have this problem?

A common issue with the E9x M3.

It's the fuel tank breather/purge valve. $90 part.

https://www.ecstuning.com/b-genuine-bmw-parts/fuel-tank-breather-valve/13907838281/

Located under the intake plenum. Consider changing it when you're doing your TAs so you kill two birds with one stone.

RAETD M wrote

A common issue with the E9x M3.

It's the fuel tank breather/purge valve. $90 part.

https://www.ecstuning.com/b-genuine-bmw-parts/fuel-tank-breather-valve/13907838281/

Located under the intake plenum. Consider changing it when you're doing your TAs so you kill two birds with one stone.

Thanks for the reply, do you know if this is a sign that the throttle actuators are close to failing?

Ringtaxi wrote

Thanks for the reply, do you know if this is a sign that the throttle actuators are close to failing?

No relation to throttle actuators.

Iyzmi wrote

No relation to throttle actuators.

Is it ok to allow this idle issue to continue until I replace throttle actuators. I only drive this car a few thousand miles a year and so at this rate it could take years until TAs need to be replaced.

How many miles are on your car?

330indy wrote

How many miles are on your car?

36,000 miles.

RAETD M wrote

A common issue with the E9x M3.

It's the fuel tank breather/purge valve. $90 part.

https://www.ecstuning.com/b-genuine-bmw-parts/fuel-tank-breather-valve/13907838281/

Located under the intake plenum. Consider changing it when you're doing your TAs so you kill two birds with one stone.

I just would like to know if this idle issue after filling the gas tank is something I should fix now to prevent some problems/damage or can it wait until the throttle actuators need replacing like you say which may be a while.

Is this a problem caused by/ aggravated by overfilling gas tank?

330indy wrote

Is this a problem caused by/ aggravated by overfilling gas tank?

Correct

I replaced my fuel breather valve and the problem went away.

mine happens when I literally overfill to the point it is pouring out gasoline.. I wish I knew this prior changing out the TA's

Here is the DIY

DIY: Replace Fuel Tank Breather Valve (Fix for bouncing idle at fuel station) https://www.m3post.com/forums/showthread.php?t=1273927

The comment on replacing the actuators is more that once you have the plenum off, replacing the actuators is not much more work.

I am not aware of significant issues with 'living with it'. Stalling is more of an annoyance, unless you plan to be the getaway car!

I never overfill the car! Once the pump clicks I stop. To hear this is from overfilling isnt correct because I’ve never put gas to the point it spills out. I think I will live with it until TAs need replacing because it doesn’t affect the car while driving only a short time while vehicle is stopped after tank is full.

0_to_60 wrote

mine happens when I literally overfill to the point it is pouring out gasoline.. I wish I knew this prior changing out the TA's

You should never fill it to this point as you can damage components in the fuel system.

If I remember the progression of stalling in my car correctly, initially it only occurred after a fill up. It didn't happen every time. Then it happened just about every time. Then occasionally it would stall well after a fill up.

It is something that can be addressed with service that requires removing the plenum. The part isn't expensive, only tricky part is removing the back hose.

Let me translate...

When you need major service that involves removing the plenum, also do the fuel tank breather valve at the same time. Replacing the $60-90 part alone isn't worth the cost of the 4-5 hours of labor.

Since you have such low mileage, do the spark plugs/air filter or leaky valve cover gasket replacement and fuel tank breather valve at the same time. Spark plug service interval is 37k miles, which is crazy for platinum plugs. Use OE NGK plugs and gap them, instead of the BMW OEM p/n. Same exact part and save $$$.

You will likely have to replace the throttle valve actuators around 60-80k miles like clock work, but no need to wait.

As a test, only fill your gas tank up to 3/4 or 1/2 tank, and see if the idle problem persists. Issue might just pop up when you fill it to FULL. Not about overfilling the tank, which is not really possible. Just a flakey fuel tank breather valve part we all have to deal with. I think Bosch makes/sells the same part.

Do all this work at a good BMW Indie shop instead of the BMW dealership. Simple routine maintenance.


Cheers

nyc_dude wrote

Let me translate...

When you need major service that involves removing the plenum, also do the fuel tank breather valve at the same time. Replacing the $60-90 part alone isn't worth the cost of the 4-5 hours of labor.

Since you have such low mileage, do the spark plugs/air filter or leaky valve cover gasket replacement and fuel tank breather valve at the same time. Spark plug service interval is 37k miles, which is crazy for platinum plugs. Use OE NGK plugs and gap them, instead of the BMW OEM p/n. Same exact part and save $$$.

You will likely have to replace the throttle valve actuators around 60-80k miles like clock work, but no need to wait.

As a test, only fill your gas tank up to 3/4 or 1/2 tank, and see if the idle problem persists. Issue might just pop up when you fill it to FULL. Not about overfilling the tank, which is not really possible. Just a flakey fuel tank breather valve part we all have to deal with. I think Bosch makes/sells the same part.

Do all this work at a good BMW Indie shop instead of the BMW dealership. Simple routine maintenance.

Cheers

Thank you for this explanation I agree. I will wait until more service is required before I handle the breather. I did plugs and air filter not long ago. Next time I get gas I will try to fill 3/4 tank and see if the issue persists.