About to give up and sell the car cause of the idle.

[Integfoo]

Have been battling this cold start idle issue just like many others here. Bounces from zero to 1 and sometimes almost sounds like its gonna die. I tried posting a video on here but it doesnt like iphones i guess. So far, i have replaced the icv, spark plugs, fuel breather valve. I am at the point where i am considering selling and buying another m3. Before i do, anything else you think i should attempt 1 last time? Thanks for the help. 👍🏼

[Epoustouflant]

Originally Posted by Integfoo

Have been battling this cold start idle issue just like many others here. Bounces from zero to 1 and sometimes almost sounds like its gonna die. I tried posting a video on here but it doesnt like iphones i guess. So far, i have replaced the icv, spark plugs, fuel breather valve. I am at the point where i am considering selling and buying another m3. Before i do, anything else you think i should attempt 1 last time? Thanks for the help. 👍🏼

Was the tubing (idle strips) of the IVC changed out as well? It was sometimes the culprit in early SIBs per BMW.

Do you have a tune?
Battery / alternator?
Throttle actuators?

TAs would stall my car when they got degraded to a point of needing replacement.

[Integfoo]

Originally Posted by Epoustouflant

Was the tubing (idle strips) of the IVC changed out as well? It was sometimes the culprit in early SIBs per BMW.

Do you have a tune?
Battery / alternator?
Throttle actuators?

TAs would stall my car when they got degraded to a point of needing replacement.

I dont know if the strips were also replaced unless they came with the icv? Is that something i have to purchase separately?
I have no tune, battery is new but not sure how the alternator would cause a bouncy idle?
I was going to replace the throttle actuators too but didnt after reading on the forums and their symptoms were different than mine (i.e. always throwing codes and going into limp mode). Mine shows no codes and never has gone into limp mode.

[MJBO]

Mine’s done this for most of the two years I’ve owned it, definitely worse in the colder months. Occasionally it will stall, but most of the time it’s just stumbly for 10-15 seconds.

Holding my foot lightly on the accelerator helps, but it still dances about before settling.

I want to get it sorted, but just haven’t been bothered enough. Next service I’ll get it investigated.

[mapster37]

i had a similar issue, no codes. i replaced the fuel pressure sensor, cold starts normal after replacement

[Integfoo]

Originally Posted by mapster37

i had a similar issue, no codes. i replaced the fuel pressure sensor, cold starts normal after replacement

Hmm ok thanks for the tip!

[Integfoo]

Originally Posted by MJBO

Mine’s done this for most of the two years I’ve owned it, definitely worse in the colder months. Occasionally it will stall, but most of the time it’s just stumbly for 10-15 seconds.

Holding my foot lightly on the accelerator helps, but it still dances about before settling.

I want to get it sorted, but just haven’t been bothered enough. Next service I’ll get it investigated.

Yea im doing the same thing! But its just embarrassing cause its so damn loud and the whole city can hear how broken my car is 😂

[Integfoo]

Originally Posted by mapster37

i had a similar issue, no codes. i replaced the fuel pressure sensor, cold starts normal after replacement

Did you replace both the high and low pressure sensors?

[pbonsalb]

I had this many years ago and replaced the low pressure fuel sensor.

[Dpc2u]

Originally Posted by Integfoo

Did you replace both the high and low pressure sensors?

There is only one sensor on the s65. It is the low pressure sensor that is easily accessible right behind the airbox.

[Integfoo]

Originally Posted by Dpc2u

There is only one sensor on the s65. It is the low pressure sensor that is easily accessible right behind the airbox.

Ah ok thanks for clearing that up. I read on here that someone replaced another one that was very hard to access and called it the high pressure Fuel sensor. 🤷🏻

[Dpc2u]

You will find that there are 2 different looking sensors, one brass like the original, and a silver one. The brass one is discontinued, and is superceded by the newer silver one. the newer one uses a small adapter that you put on it before screwing it in place. They both go in the same location and do the same thing. You can still find the brass one if you dig around. I changed mine a year ago and used the brass one. It's a pretty simple fix with the right flex head wrench. I didn't have to remove the airbox though most people do. Took 10 minutes to swap it.

I hope that changing it will get your issue resolved. I never had any drivability issues, just a code that would pop up on long drives. Never had the code again after I swapped it out.

https://www.ebay.com/itm/151734140904

[Integfoo]

Originally Posted by Dpc2u

You will find that there are 2 different looking sensors, one brass like the original, and a silver one. The brass one is discontinued, and is superceded by the newer silver one. the newer one uses a small adapter that you put on it before screwing it in place. They both go in the same location and do the same thing. You can still find the brass one if you dig around. I changed mine a year ago and used the brass one. It's a pretty simple fix with the right flex head wrench. I didn't have to remove the airbox though most people do. Took 10 minutes to swap it.

I hope that changing it will get your issue resolved. I never had any drivability issues, just a code that would pop up on long drives. Never had the code again after I swapped it out.

https://www.ebay.com/itm/151734140904

Thanks a bunch! I have ordered the new version with the adapter. Hopefully this will solve the problem. Although mine is not throwing any codes like yours did.

[pbonsalb]

Mine did not throw codes either. It simply occasionally stumbled when idling, like when stopped for a traffic light.

[Integfoo]

Originally Posted by pbonsalb

Mine did not throw codes either. It simply occasionally stumbled when idling, like when stopped for a traffic light.

Ah ok i see. Mine only has an issue at cold start after sitting over night and is fine for the rest of the day.

[SG_E90]

You don't think it can be anything related to the secondary air pump, maybe clogged?

[pbonsalb]

I agree that a cold start related stumble may be different than a fuel pressure sensor related stumble.

[Kwike92M3]

What are you selling the car for?!

[GORDON.M3]

Sounds like you have a leak or a bad sensor. I would check the fuel pressure sensor. Happened to a buddy of mine.