[Eddien123]

Hey all. I've noticed lately when I pull out of the garage and the cars stone cold, when accelerating on my driveway in first it seems to cut and add power in a surging form. Basically the only way to stop it is to clutch in and just grab second. Doesn't seem to do it on the road just under light acceleration in my driveway and only when the cars cold. Any ideas?

Car is a 335 6MT

[F36GC_NYC]

Originally Posted by Eddien123

Hey all. I've noticed lately when I pull out of the garage and the cars stone cold, when accelerating on my driveway in first it seems to cut and add power in a surging form. Basically the only way to stop it is to clutch in and just grab second. Doesn't seem to do it on the road just under light acceleration in my driveway and only when the cars cold. Any ideas?

Car is a 335 6MT

i noticed this after i did the stage 2 tune, but its ONLY when the car is cold... i can see the revs climb but my movement in relation to that doesnt seem to match up....(it sometimes even feels jerky)

but once the car is warm its fine, i just figured the car needs to be warm and problem solved....but it is worth mentioning before i did any kind of modifications i never had this issue.

i have the 8 AT..

[Eddien123]

Originally Posted by F36GC_NYC

i noticed this after i did the stage 2 tune, but its ONLY when the car is cold... i can see the revs climb but my movement in relation to that doesnt seem to match up....

but once the car is warm its fine, i just figured the car needs to be warm and problem solved....but it is worth mentioning before i did any kind of modifications i never had this issue.

Car is also tuned. Occasionally it'll throw a lean air mixture code perhaps when the cars cold the fueling gets screwed up until cylinder temps come up. However this cars been tuned for a while and this is a new issue

[4dirty5]

Same issue during a cold start. I believe (correct me if I'm wrong) the car idles at 750 RPM during a cold start. Once the engine warms up, it should drop down by ~200-300 RPM and you should be clear to take off. During the cold mornings in the east coast, I turn my car on and let it idle for about 5-10 minutes while I pack my breakfast/make coffee and it doesn't buck and isn't jumpy.

[Eddien123]

Originally Posted by 4dirty5

Same issue during a cold start. I believe (correct me if I'm wrong) the car idles at 750 RPM during a cold start. Once the engine warms up, it should drop down by ~200-300 RPM and you should be clear to take off. During the cold mornings in the east coast, I turn my car on and let it idle for about 5-10 minutes while I pack my breakfast/make coffee and it doesn't buck and isn't jumpy.

I definitely don't give it a 10 min idle warm up but the RPMs have definitely settled to regular idle before I set off. Last night fully warmed up I did a pull in second and it didn't buck but you could tell power was being withheld and after about 4000, it just took off. So I have some investigating to do. I may remove the dinan tune and go stage 2 BM3 maybe it's a tune issue

[bpwj76]

My bone stock 320i with 8AT does the same thing. Only does it once after backing out of garage and starting up the driveway. There's a stop sign about half a mile down the road and it never does it there. Only in the driveway.

I've also never tried letting it warm up first. Will give it a shot and see.

[4dirty5]

Originally Posted by Eddien123

I definitely don't give it a 10 min idle warm up but the RPMs have definitely settled to regular idle before I set off. Last night fully warmed up I did a pull in second and it didn't buck but you could tell power was being withheld and after about 4000, it just took off. So I have some investigating to do. I may remove the dinan tune and go stage 2 BM3 maybe it's a tune issue

For what it's worth, I'm FBO with Stage 2 BM3 AGG. I don't think it has much to do with the tune more than it does just letting it sit and warm up. It could be the engine needs a little more time than standard cars. I remember the same issue in my 370z Nismo. First would buck but after that initial drive off, it doesn't happen again unless the car sits for 15+ hours.

Curious, how long do you let it sit before driving off?

[hrdboiled]

I had same exact issue. 335i 6mt stage 1 tune. When cold in 1st car would surge forward like I forgot how to drive stick. Only happened when cold and in 1st. I had learned to live with it. Then my battery went out. After I changed my battery the surge completely went away. This was almost a year ago, it's still good.

I can't explain how or if the 2 are related but It's still not surging.

[Eddien123]

Originally Posted by hrdboiled

I had same exact issue. 335i 6mt stage 1 tune. When cold in 1st car would surge forward like I forgot how to drive stick. Only happened when cold and in 1st. I had learned to live with it. Then my battery went out. After I changed my battery the surge completely went away. This was almost a year ago, it's still good.

I can't explain how or if the 2 are related but It's still not surging.

Woooow that is so strange because I just recently started getting slow cranks and "battery discharge warning". My battery is no doubt shot. You might be onto something

[hrdboiled]

I knew my battery was on it's last legs b/c it was taking a little longer to crank. The surging was happening more and more- even when the car was sitting for a couple hours. After I changed my battery and pushed the start stop I was like "damn that turned over super quick." Guess I got so used to the old battery haha.

Anyway- keep us updated.

[Korvo]

Same issue tuned with BM3. JaredG_F30 determined that a throttle recalibration fixed his issue. I tried it and it seems to work!

[Eddien123]

Originally Posted by pdegene

Same issue tuned with BM3. JaredG_F30 determined that a throttle recalibration fixed his issue. I tried it and it seems to work!

Was thinking of dropping the Dinan tune for BM3. Just have to go through the haste of disconnecting everything. To be honest i May just take it to kies motorsports in Jersey to have him do it all. Cars equipped to run stage 2 so that would be sweet

[Mouse]

My bet is battery is about to give up the ghost. I had exact same issue and my battery died a few months later. New battery fixed up cold start bucking and other odd issues. (I was tuned as well.)

[Eddien123]

Originally Posted by Mouse

My bet is battery is about to give up the ghost. I had exact same issue and my battery died a few months later. New battery fixed up cold start bucking and other odd issues. (I was tuned as well.)

Amazing how electrically based these cars are now...

[pshovest]

What's the date code on the battery?
Connect laptop w/ISTA and read the state of charge of the battery.
This is easy to confirm or rule out. Put a 10 amp charger on battery overnight.

[Eddien123]

Originally Posted by pshovest

What's the date code on the battery?
Connect laptop w/ISTA and read the state of charge of the battery.
This is easy to confirm or rule out. Put a 10 amp charger on battery overnight.

I will check. I did an overnight charge last week and within a day it went back to a slow crank. And OB2 reader I attached claimed it's max potential charge was like 57% or something. I'm just going to grab a new one. It wasn't really a priority because the car is not daily driven and it sits in a warm garage yanno so I Never really experienced cold weather starts

[pshovest]

Originally Posted by Eddien123

....... Occasionally it'll throw a lean air mixture code.......

Don't have any experience with tunes, but cold start driveability issues in my experience are almost always mixture related.

If you get the chance, try the charger again and see if the driveability issue disappears even if only for (1) drive.

[Eddien123]

Originally Posted by pshovest

Don't have any experience with tunes, but cold start driveability issues in my experience are almost always mixture related.

If you get the chance, try the charger again and see if the driveability issue disappears even if only for (1) drive.

Will do. Thanks for the advice!

[paul e]

I keep my Miata - another non-daily usage car - on a “float” charger. This type puts a small current into the battery WHEN NEEDED and shuts off until another small charge is needed.

[DadzBmer_N2o]

Originally Posted by 4dirty5

For what it's worth, I'm FBO with Stage 2 BM3 AGG. I don't think it has much to do with the tune more than it does just letting it sit and warm up. It could be the engine needs a little more time than standard cars. I remember the same issue in my 370z Nismo. First would buck but after that initial drive off, it doesn't happen again unless the car sits for 15+ hours.

Curious, how long do you let it sit before driving off?

Originally Posted by 4dirty5

Same issue during a cold start. I believe (correct me if I'm wrong) the car idles at 750 RPM during a cold start. Once the engine warms up, it should drop down by ~200-300 RPM and you should be clear to take off. During the cold mornings in the east coast, I turn my car on and let it idle for about 5-10 minutes while I pack my breakfast/make coffee and it doesn't buck and isn't jumpy.

So glad someone brought this up, as i was gonna do more searching but then i saw these. I have Stage 1 - 93 BM3 and it does this as well in this cold weather now..

[thompsac25]

I have noticed this happening more frequently in the colder months. Same thing though - I start the car, pull out of the garage and down the driveway, then the surge starts as soon as I take off. Theres a stop sign at the end of my street and it doesnt happen when I take off from that stop. So its just initially when its a super cold start. I think the car just needs to warm a little. My car is completely stock motor, no tune etc. just a BMW MPPK.

[Eddien123]

Originally Posted by thompsac25

I have noticed this happening more frequently in the colder months. Same thing though - I start the car, pull out of the garage and down the driveway, then the surge starts as soon as I take off. Theres a stop sign at the end of my street and it doesnt happen when I take off from that stop. So its just initially when its a super cold start. I think the car just needs to warm a little. My car is completely stock motor, no tune etc. just a BMW MPPK.

Are you auto or manual?