I've noted this for a while, but have recently become more aware of it. If I idle and then "punch it" there is a distinct "bog" as if the engine hesitates and it wants me to rev slower. This doesn't occur when the revs are already up.

Is it more noticable b/c I have a cold air intake? The car runs strong as ever, and I haven't noted a change in performance. It is of concern? Does your "S" do this?


His, Chile RED over, Madness intake, Magnaflow, Helix Pulley & RDR Swaybar
Hers, Electric Blue / Union Jack on top and BONE Stock

 

Does it sound like a champaign bottle uncorking? Not the pop but the air escaping sound... Or a vacuum cleaner when you pull the sucked in paper out? It's the air being sucked hard into the engine, you can hear it loud and clear with the intake.

Motor On!

 

I think you're talking about the "stumble"...I have it, as do many others. Try a search on the word "stumble" on the site here, you'll probably find some useful info...

If you can provide more info on your MCS (build date, etc.), some of the more knowledgeable folks on here might be better able to help.

If it helps, there are a number of folks here who can empathize!


_________________
<IMG SRC="https://www.northamericanmotoring.co....jpg"> BLK MCS All 3 packages...I call him...Buster.

 

I'm don't think it's the dreaded stumble, unless I'm misunderstanding the stumble. It only happens only when the RPMs are at idle and then the throttle is punched fast and hard. When driving acceleration is smooth.(for the most part)

I don't think I can describe the sound.

It reminds me of my 2 stroke Suzuki '74 TS 100 I owened as a lad. From idle to full throttle there is a hesitation as if the motor is "choking" on too much fuel/air. There is a delay in the increase in RPMs, a "bog".

My "S" is an Aug 02 build.

Is there is anyone willing to start their "S", let it idle for a bit and then punch it fast and hard and see if there is a hesitation.

Additionally, I think I have recently developed the cold start issue as it starts and then dies on first start. Subsequent starts are smooth and brisk

 

The engine "bog" you describe is a known issue with the engine management. There are three issues related to the software:

1. Stumble/hiccup (momentary engine cutout in 1st gear launch)
2. Engine Bog (slow acceleration no matter how much throttle is applied, occurs infrequently and without warning)
3. Yo-yo acceleration (acceleration oscillates usually in the 3000-4000 rpm

Your situation sounds a little different, since you can cause the bog on-demand. Probably still related, though.

We're all waiting on a fix...and waiting...and waiting...and waiting...

See ya,
JS

 

Okay, I have all 3 issues with my S, is there anything that can be done about it?
>>
>>See ya,
>>JS

 

>>Okay, I have all 3 issues with my S, is there anything that can be done about it?
>>>>
>>>>See ya,
>>>>JS
>>

Tell everyone you can that may be interested in buying a Mini about these problems. It's not right and BMW should not sell any car with these issues.

 

This might be too obvious so forgive me if you already ruled this out, but might you be triggering the ASC/DSC with a little wheel slippage? Try turning off your traction control and doing the same hard start, you should now lay a nice bit of runflat on the pavement rather than bog.

If that's not it I would then refer to the above posts.

Jim