IAC valve same as fuel tank breaker valve?

[eswaroop]

Hey there - quick q - is the fuel tank breather valve same as the idle air control valve on these cars?

If not where’s the idle control valve located? I found the fuel tank breather valve as the one in the valley

[eswaroop]

Originally Posted by eswaroop

Hey there - quick q - is the fuel tank breather valve same as the idle air control valve on these cars?

If not where’s the idle control valve located? I found the fuel tank breather valve as the one in the valley

Guessing they are not

ICV is p/n 13417838024

FBV is p/n 13907838281

Which one may be responsible for hesitation during acceleration? If either..

[drwankel]

IAC, which means idle air control valve, (different manufacturers call it different things) is a valve that controls your idle speed, allowing the correct amount of air past the throttle plates to keep the engine running at the desired idle speed.

A fuel tank breather valve controls the pressure in the fuel tank.

[VictorH]

AS above they have different functions. Both are on top of your engine under the plenum (I've replaced both). Fuel tank breather is cheap and pretty easy to get at, but idle control valve is expensive and a bit deeper in the "V"

If your car dies after getting gas at the gas station while sitting at a red light, and idle speed hunts up and down, get a new fuel tank breather valve.

If you car, upon cold start, has a hunting idle and dies when cold, then consider replacing the idle control valve.

[1BlackDropTop]

Originally Posted by VictorH

AS above they have different functions. Both are on top of your engine under the plenum (I've replaced both). Fuel tank breather is cheap and pretty easy to get at, but idle control valve is expensive and a bit deeper in the "V"

If your car dies after getting gas at the gas station while sitting at a red light, and idle speed hunts up and down, get a new fuel tank breather valve.

If you car, upon cold start, has a hunting idle and dies when cold, then consider replacing the idle control valve.

Running into this issue myself... although none of the above scenarios has occurred to me. After some spirited driving I came to a red light and boom. Idles drop below 500 then bounce back above normal then back down, back and forth. I'm thinking ICV...

[wfdeacon88]

Originally Posted by 1BlackDropTop

Running into this issue myself... although none of the above scenarios has occurred to me. After some spirited driving I came to a red light and boom. Idles drop below 500 then bounce back above normal then back down, back and forth. I'm thinking ICV...

I was told on here a few days ago (having the same issue as you) that ICV throws codes and check engine light, while FBV doesn't, so I'm thinking FBV...

[M3BatMobile]

Originally Posted by 1BlackDropTop

Running into this issue myself... although none of the above scenarios has occurred to me. After some spirited driving I came to a red light and boom. Idles drop below 500 then bounce back above normal then back down, back and forth. I'm thinking ICV...

Same here. but i can't find a pattern. 2-3 x per week (driving me crazy), hot or cold, when i come to a stop the idle drops and seems if the car will stall (It did once) and then the idle picks up. I just did a smoke test which came up clean.

It's a 2011 w/138k miles, manual trans. I'm at the end of a 2018 refresh with this car, owned it since new and this pops up in the last 2 months.

within the last 6 mos I've replaced; actuators, ignition coils & plugs, rod bearings ... she's running like new except this one problem/ hiccup.

any ideas?

[eswaroop]

Which one If either causes surging and hesitation at cold start and run in first and even sometimes second gear? Not as much the idle speed but the car itself - surges, pulls back and surges again ? Or is it just bad gas ?

[kscarrol]

Having had the FBV issue, what you describe is not the FBV... FBV causes idle to drop while idling at a stop light. It will bounce back up above normal levels briefly but not surging. And I never had the issue at cold start up, usually after filling the tank.

[RedCardinal]

Originally Posted by M3BatMobile

Same here. but i can't find a pattern. 2-3 x per week (driving me crazy), hot or cold, when i come to a stop the idle drops and seems if the car will stall (It did once) and then the idle picks up. I just did a smoke test which came up clean.

It's a 2011 w/138k miles, manual trans. I'm at the end of a 2018 refresh with this car, owned it since new and this pops up in the last 2 months.

within the last 6 mos I've replaced; actuators, ignition coils & plugs, rod bearings ... she's running like new except this one problem/ hiccup.

any ideas?

Wondering if you solved this. My car almost stalled twice today after getting gas and I've had it stall before after fueling but it's very intermittent. no codes being thrown.

[drrust]

Originally Posted by RedCardinal

Wondering if you solved this. My car almost stalled twice today after getting gas and I've had it stall before after fueling but it's very intermittent. no codes being thrown.

If it occurs after a fill up, it is the fuel tank breather valve.

[Merlin_83]

I think that special emissions warranty will or should cover the cost of replacement of either of those items.

I can look up the actual link if people want, but there's some posts here on Bimmerpost that should be searchable and reference how the special fuel and emissions warranty works.

It's possible I may be incorrect- but double check to see if either of those items are covered.

Cheers,
Merlin

[M_island]

Originally Posted by drrust

If it occurs after a fill up, it is the fuel tank breather valve.

100% confirmed. Had mine replaced today. Failed at 115k km. Only sputtery idle after fill up on an 09 dct.

[TX]

Originally Posted by Merlin_83

I think that special emissions warranty will or should cover the cost of replacement of either of those items.

I can look up the actual link if people want, but there's some posts here on Bimmerpost that should be searchable and reference how the special fuel and emissions warranty works.

It's possible I may be incorrect- but double check to see if either of those items are covered.

Cheers,
Merlin

I thought that was only valid in Cali?

[Merlin_83]

Originally Posted by TX

I thought that was only valid in Cali?

The warranty covers many states including California- try doing a search but there existed an official BMW technical bulletin and lists I think about 7 or 8 states that have to/must follow the same wording of the warranty.