Anyone has idle issue after catless downpipe?

[wuziyue]

Did the vrsf catless downpipe on the f85 x5m and it sounds good but there is rough idle problem during cold start in the morning( in park or neutral) and it caused stalls if I don't push the accelerator to keep the rpm over 1000. It turned out good after(the temperature goes up). There is no faulty code from obd port and even if I flash the bm3 on the car, the problem still persist, the o2 sensors are in the right place. Any one had the issue? Please help. Thank you!

[Ehloo]

Heard of a similar issue from another member with a different tune. Figured it was tune related.

I am running hfc dp and don’t have the issue. Do you have the updated maps from bm3

Originally Posted by wuziyue

Did the vrsf catless downpipe on the f85 x5m and it sounds good but there is rough idle problem during cold start in the morning( in park or neutral) and it caused stalls if I don't push the accelerator to keep the rpm over 1000. It turned out good after(the temperature goes up). There is no faulty code from obd port and even if I flash the bm3 on the car, the problem still persist, the o2 sensors are in the right place. Any one had the issue? Please help. Thank you!

[wuziyue]

Originally Posted by Ehloo

Heard of a similar issue from another member with a different tune. Figured it was tune related.

I am running hfc dp and don’t have the issue. Do you have the updated maps from bm3

Yes I think so, it's version 2.2 released on March 2019. Do you have any tune on yours? Is it because the x5m meant to have a cat?

[Ehloo]

I’m running bm3 also. Not sure what version. Most likely the March 2019 when they released their burble

The stage 2 is suppose to be for cars with no cats or hfc.

Is the weather getting colder where you are at. I have heard rough idle with colder temps

Originally Posted by wuziyue

Yes I think so, it's version 2.2 released on March 2019. Do you have any tune on yours? Is it because the x5m meant to have a cat?

[Crisp]

Originally Posted by wuziyue

Did the vrsf catless downpipe on the f85 x5m and it sounds good but there is rough idle problem during cold start in the morning( in park or neutral) and it caused stalls if I don't push the accelerator to keep the rpm over 1000. It turned out good after(the temperature goes up). There is no faulty code from obd port and even if I flash the bm3 on the car, the problem still persist, the o2 sensors are in the right place. Any one had the issue? Please help. Thank you!

Have you altered the OEM cold start procedure?
How long has this been going on?

There's no error code even if you let the car stall?

[Crisp]

Originally Posted by Ehloo

I’m running bm3 also. Not sure what version. Most likely the March 2019 when they released their burble

The stage 2 is suppose to be for cars with no cats or hfc.

Is the weather getting colder where you are at. I have heard rough idle with colder temps

Yes, but it's not a requirement to be in Stg 2 if you change down pipes. You can stay Stg 1, but you won't get the extra power from the tune to accommodate the free flowing exhaust.

[ICBM]

I am also having the same issue with my x6m. Sometimes will stall if I let the engine run longer after the initial warm up. Sometimes idle it's fine, sometimes some small fluctuations. This is only happen at cold start, but it did happen once at a stop light. And it is summer. I was first running the tune with stock downpipes, everything was ok. This start happening after the catless dp. What I usually do I won't let the engine idle anything longer than needs - as soon as the warm up finishes I start driving. Everything else seems to be fine, except of some annoying noises that now can be heard since going catless. And a newly squeaking noise I now start hearing at idle and I suspect it is coming from a pulley or something. Not very loud atm but it is concerning and I will start investigate soon. My tuner is Velos, idle fluctuations happen with crackle and non crackle tune as well. Catless dp I have are the 3.5"

[notyourdadsf86]

Most of my research has led me to conclude theres no real answer here. I've read everything from stock cars stalling, to catless do causing it. Seen people put cats back on and stalling goes away but comes back. Stock guys took their cars to dealers for service and BMW never gave them a fix. At least none that I've found. Everyone I talk to just says that it's an issue for these trucks regardless.

[Lighting.Grey]

Originally Posted by notyourdadsf86

Most of my research has led me to conclude theres no real answer here. I've read everything from stock cars stalling, to catless do causing it. Seen people put cats back on and stalling goes away but comes back. Stock guys took their cars to dealers for service and BMW never gave them a fix. At least none that I've found. Everyone I talk to just says that it's an issue for these trucks regardless.

I mean what if you just let it stall? Does it really matter, I know it feels bad but does it hurt our vehicles?

[Lighting.Grey]

Originally Posted by Crisp

Have you altered the OEM cold start procedure?
How long has this been going on?

There's no error code even if you let the car stall?

Just curious here, what is the actual OEM recommendations for the cold start? When I first purchased my X6M, I read that we should let the engine warm up by slow gentle driving, don't need to wait until it warms up.

[Lighting.Grey]

I think this could happen to any F85/F86 out there, doesn't matter if it's new or old, with mods or without mods. I remember back in the days I went to my dealer to check out the brand new X6M, it was cold winter and as soon as I fired it up, after 10-15 seconds, the rpm dropped below 1000, then it felt like it's gonna to stall.

[adonnan]

No stalling to report here, just a really active fuel gauge with 90% city driving.

[F3085258]

No stalling here with VRSF catless DP AND BM3 stage 2. I do get a lumpy idle some times. Ambient temp doesn't seem to matter. I did do cold start delete and set the rpm up a couple hundred from normal in the warm up cycle.