Cold start & low-speed surging on 240E?

[dparm]

I had the 240E integration loaded about a month ago but I feel like the car is really surging and lurching right after it has been started (i.e. the first two or three minutes). Would describe it as feeling like someone is pulsating the gas pedal rather slowly. M-DCT also feels like it is taking its dear-sweet time to engage gears.

Any other 240E folks experience this?

[swartzentruber]

Are you still having lingering issues related to this low RPM surging at cold startup (with 240E), or has it gone away. I had my M3 upgraded earlier this year to 240E, and just lately have had a few issues with this type of surging when idling (700 - 1200 rpm, goes away after the first few minutes). I'm trying to figure out if this is something related to 240E, since I never noticed it in prior years), or if I have a mildly bad tank of gas, or something else is going on. Anyone else that has had issues with this kind of idle surging feel free to chime in as well.

[BPMSport]

Depending on what version you had before, the cold start strategy of 240E is more aggressive and it's normal to experience rougher starts. However, lots of idle jumping is not normal IMO, although dealerships like to say it is.

[W///]

Originally Posted by dparm

I had the 240E integration loaded about a month ago but I feel like the car is really surging and lurching right after it has been started (i.e. the first two or three minutes). Would describe it as feeling like someone is pulsating the gas pedal rather slowly. M-DCT also feels like it is taking its dear-sweet time to engage gears.

Any other 240E folks experience this?

Yea mine used to surge like crazy. To the point where I had to clutch in because it was bucking so hard. But that only happened when I started the car and took off almost immediately.

It's more or less gone with BPM dev tune though.

[dparm]

Originally Posted by Mike Benvo

Depending on what version you had before, the cold start strategy of 240E is more aggressive and it's normal to experience rougher starts. However, lots of idle jumping is not normal IMO, although dealerships like to say it is.

Yeah, the dealer confirmed this. The cold start jerkiness is somewhat normal. It's referred to as "bucking bronco syndrome".

[nullrouted]

Originally Posted by dparm

Yeah, the dealer confirmed this. The cold start jerkiness is somewhat normal. It's referred to as "bucking bronco syndrome".

I find that letting the car idle for about 60-90 seconds or so (however long the cold start routine is) until the idle drops down to normal cures the "syndrome" for me.

[dparm]

Originally Posted by nullrouted

I find that letting the car idle for about 60-90 seconds or so (however long the cold start routine is) until the idle drops down to normal cures the "syndrome" for me.

That's what the dealer told me: wait a minute and then drive off. It's an NVH concern and is there for emissions reasons.

[ThatGuyMikee]

Happend to my 08, never done this till after the dealer, they said it was normal, after about a week it never happend again, i think the new software has to get used to things

[C|3R1C]

When I had cold start my car was rough as hell. If I let the sequence complete, it was way smoother. And now with cold start gone, I let my car warm up for a few minutes depending how cold it is and it begins wayyyyy smoother.

[dparm]

Originally Posted by C|3R1C

When I had cold start my car was rough as hell. If I let the sequence complete, it was way smoother. And now with cold start gone, I let my car warm up for a few minutes depending how cold it is and it begins wayyyyy smoother.

Letting your car warm up for a few minutes is not going to help engine longevity.

[rsv4dan]

I recently updated my 08 6MT to the latest software. Can anyone tell me why it runs the cold start cycle 90% of starts whether hot or cold?? It will obviously do it when it's cold. It will do it 95% of the time if the car is stopped for a couple of minutes(ie stop for fuel) and it will do it 50% of the time if the car has been sitting for 20-30 minutes and cooled a little.

[BPMSport]

Normal operation. The cycle is not only present on dead cold starts, but also if the car has been sitting for a few minutes as well. This ensures that the cats are at operating temperature after a slight cool off.

[stevens]

for us in the UK it was also down to fuel, a lot of M3s here suffered this more than most when using Shell Optimax (not sure if you have this in the US) where revs would move up and down a lot and general jerky pulling away on DCT until the cold start cycle had finished, another fuel type (all 97-99 RON) and it immediately went away.

[spool twice]

Originally Posted by Mike Benvo

Normal operation. The cycle is not only present on dead cold starts, but also if the car has been sitting for a few minutes as well. This ensures that the cats are at operating temperature after a slight cool off.

Mike, does the cold start induce a lean-burn state? Does it use any more fuel than the cold-start delete? I've always been curious.

I recall on my 240E, the idle surging was more prominent during a warm engine/cold start sequence with the OEM software vs. a cold engine/cold start sequence.

[sylonien]

Originally Posted by dparm

Letting your car warm up for a few minutes is not going to help engine longevity.

Is that a fact or a endless internet debate?

[dparm]

Originally Posted by sylonien

Is that a fact or a endless internet debate?

It's a fact. The car runs in open loop mode which means it runs rich:

-contaminates oil with fuel
-pollutes like crazy
-unnecessarily pumps cold/thick oil through engine
-potentially fouls plugs and/or oxygen sensors

Engine LOAD will warm the car up much more quickly and smoothly.

[sylonien]

Sorry one more slight deviation from original thread.

Is it ok to run engine cold when you're de-icing the car?