post Fill up stall/misfire

e90 m3 with 135,000 mi all major maintenance pretty much up to speed however last three to four fill ups having stalling sputtering and slow restart. Just had my MTL pump changed. shop is thinking fuel pump might be going out. It has done this stall sputter thing once or twice at stop light. Just wanted to check and see before moving forward with fuel pump if anyone thinks it could be anything else only codes that have been thrown are misfires in all cylinders.... shop first took a look at it after installed at the stoplight right near the shop and they told me there was no fuel found in the overflow thing I can't remember what it's called but they said fuel pump likely wouldn't throw codes.. car otherwise is pretty much in good shape rod bearings etc all completed since requiring it 4 years ago.

Also last year did spark a new valve covers etc. Just wanted to check if it could be idle control valve or fuel breather for the expensive fuel pump decision.

Apologize for grammar using voice to type while driving

Sounds to me like it could be the fuel breather valve

dmz_m3 wrote

Sounds to me like it could be the fuel breather valve

that would be phenomenal.. could it still be that if the overflow tank think was empty? that's what we found when checked.... forgive my incorrect naming

dmz_m3 wrote

Sounds to me like it could be the fuel breather valve

^This. Sounds like pretty classic signs.

tbuck wrote

dmz_m3 wrote

Sounds to me like it could be the fuel breather valve

^This. Sounds like pretty classic signs.

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

going to give this a try, don't want to risk $1100 on a fuel pump replacement if it's just this part... is this the only part I need?

Prior to dumping that type of cash on a pump I would check and see what type of pressure you are getting out of it. Unless the shop specializes in BMW they likely defaulted to "sounds like the fuel pump" because they have no idea what else it could be. Without pressure testing the pump it would be silly just to throw another one on there.

There are numerous threads on this issue and it sounds like you are suffering from the breather valve failure which is not uncommon.

https://www.m3post.com/forums/showthread.php?t=1273927

tbuck wrote

Prior to dumping that type of cash on a pump I would check and see what type of pressure you are getting out of it. Unless the shop specializes in BMW they likely defaulted to "sounds like the fuel pump" because they have no idea what else it could be. Without pressure testing the pump it would be silly just to throw another one on there.

There are numerous threads on this issue and it sounds like you are suffering from the breather valve failure which is not uncommon.

https://www.m3post.com/forums/showthread.php?t=1273927

they are specialty BMC, Porche... very good shop, but the master BMW tech was out the day I brought it in, very late in the day after a stall out. But, this shop has never ever tried to upsell me on anything, trust them 100% based on the last 4 years they have been incredible to me and the car. But they hooked it up, ran codes (only misfires), and drove it around (nothing happened for them), checked the overflow canister thing, etc.. they are going to swap the fuel breather valve first this week, hopefully that's the fix. It's still on original so worth a shot. hopefully that's it.. thanks for the link and information, fingers crossed!

wfdeacon88 wrote

tbuck wrote

dmz_m3 wrote

Sounds to me like it could be the fuel breather valve

^This. Sounds like pretty classic signs.

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

going to give this a try, don't want to risk $1100 on a fuel pump replacement if it's just this part... is this the only part I need?

If you're replacing it yourself you may want to get the kit with the hose. The connector to the valve can be difficult to remove.

https://www.ecstuning.com/b-assembled-by-ecs-parts/fuel-tank-breather-valve/13907838281kt/