[TheJungatron]

Update - 12/29/2020

Seems solved. Haven seen the issue after reverting to stock, resetting adaptations then retuning and again resetting adaptations.




Updated - bm3 log 11.30.2020

https://www.bootmod3.net/log?id=5fbf...0b434a0a882a4a

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2015 335i A8, rwd, mp lsd, 45,500 miles.

The car has been fantastic, but I haven't been driving it as much due to working from home since March.

My cold starts seem like it struggles or strange when it kicks over. the rpms bounce low then catch them self after half a second or it take a bit longer to kick over then rpm bounce weird. Just doesn't sound right. I'll turn it off and try it again and less issues or no issues.

It's like it hates cold starts sometimes.

Wondering if anyone has seen a rough cold start in mornings but then the rest of the day no issue, starts like a champ.

No misfires or issues. Coils and plugs replaced in July of this year.

Original battery as I purchased the car in 2017

Always running 93

Cleaned the MAF and no change. Still weird starts when the car sits for a days.


No codes in Cody or BM3

[thejeremyman9]

If you just mean the car needs a little more time from the time you press the button to the time the engine is actually running and/or the cold start seems a little more difficult after the car has been sitting for an extended period of time (say, 1 week or more), i would say that's normal, especially if the next cold start say a day later is normal again.

I'm in the same boat about infrequent driving and i thought i observed that last time. I havent started my car in about a week in a half and will be either tonight or tomorrow morning and will pay careful attention and report back.

[TheJungatron]

Originally Posted by thejeremyman9

If you just mean the car needs a little more time from the time you press the button to the time the engine is actually running and/or the cold start seems a little more difficult after the car has been sitting for an extended period of time (say, 1 week or more), i would say that's normal, especially if the next cold start say a day later is normal again.

I'm in the same boat about infrequent driving and i thought i observed that last time. I havent started my car in about a week in a half and will be either tonight or tomorrow morning and will pay careful attention and report back.

Yeah, it's hard to explain what's happening. I'm going to record it the next couple times.

[thejeremyman9]

My cold start is definitely a little different after the car has been sitting for over a week. Its just not as 'smooth' when it first starts idling. Sometimes it takes a second longer to fire, sometimes it doesnt. Goes away quickly and doesn't do it again until the car sits a while. It still cranks over completely fine FYI; if you have weird cranking that could be something else.

[TheJungatron]

Originally Posted by thejeremyman9

My cold start is definitely a little different after the car has been sitting for over a week. Its just not as 'smooth' when it first starts idling. Sometimes it takes a second longer to fire, sometimes it doesnt. Goes away quickly and doesn't do it again until the car sits a while. It still cranks over completely fine FYI; if you have weird cranking that could be something else.

The car never really sits for a week. Its more like 2 days or so and the first start is strange like it doesn't turn over immediately.

Today I recorded the start up and it was smooth. No issues, however I did drive more this week. It only sat for about 24 hours.

Ill leave it sit and try and get a recording in the next couple days.

[Pray for Mojo]

Mine does the same, it's sat a lot during the last 6 months and for a while it did that almost every time. I ended up turning GTS roar on because with cold start off it didn't like idling when first started.

[TheJungatron]

Short clip of the start up, of course it didn't stutter that much. I'll see if I can get a better one at some point

[TheJungatron]

Still did it a bit today. I'm really leaning towards battery replacement as my starting point if it keeps up.

[thejeremyman9]

Originally Posted by Jungatron

Still did it a bit today. I'm really leaning towards battery replacement as my starting point if it keeps up.

I do not think its battery. Usually when battery starts to go you get a slew of different codes and you would also expect the actual cranking to be impacted. Most people get 5-7 or even more years from their batteries depending of course on usage and where they live.

In the video you posted previously i only saw a fraction of a second of hesitation on the first start and then it idles just fine, and the cranking did not sound like there was any battery issue...

Just saying that battery issue usually shows up in other ways besides what you are describing.

[TheJungatron]

Originally Posted by thejeremyman9

I do not think its battery. Usually when battery starts to go you get a slew of different codes and you would also expect the actual cranking to be impacted. Most people get 5-7 or even more years from their batteries depending of course on usage and where they live.

In the video you posted previously i only saw a fraction of a second of hesitation on the first start and then it idles just fine, and the cranking did not sound like there was any battery issue...

Just saying that battery issue usually shows up in other ways besides what you are describing.

Thanks Jeremyman,

The car is a 2015 which puts the battery at over 5 years and we live in florida so the heat tends to kill them quicker... I will try and let it sit for a couple days and try it again. I'm running out of ideas as it doesn't throw any codes and it just doesn't sound right sometime when I let it sit.

[thejeremyman9]

Originally Posted by Jungatron

Thanks Jeremyman,

The car is a 2015 which puts the battery at over 5 years and we live in florida so the heat tends to kill them quicker... I will try and let it sit for a couple days and try it again. I'm running out of ideas as it doesn't throw any codes and it just doesn't sound right sometime when I let it sit.

You could also consider putting a maintainer on it and see if it changes the symptoms at all... and/or you can check battery voltage after sitting and during cranking. If it does't drop outside normal range i would suspect battery is fine. Its usually the 2012-2013s you see starting to have failing batteries now, but YMMV.

There's another thread on potential cold start issues now too. The question is really how much variation is 'normal'. As i mentioned there you can also give everything underhood a good visual/physical inspection. It's quite possible that cars are just sitting more/longer now and the decrease in driving frequency is affecting the cold starts, so people are noticing things are different sometimes and are seeking answers/explanation. The average person would probably not notice or just completely disregard many of these small things but of course here on the forums we all pursue perfection

[TheJungatron]

Originally Posted by thejeremyman9

You could also consider putting a maintainer on it and see if it changes the symptoms at all... and/or you can check battery voltage after sitting and during cranking. If it does't drop outside normal range i would suspect battery is fine. Its usually the 2012-2013s you see starting to have failing batteries now, but YMMV.

There's another thread on potential cold start issues now too. The question is really how much variation is 'normal'. As i mentioned there you can also give everything underhood a good visual/physical inspection. It's quite possible that cars are just sitting more/longer now and the decrease in driving frequency is affecting the cold starts, so people are noticing things are different sometimes and are seeking answers/explanation. The average person would probably not notice or just completely disregard many of these small things but of course here on the forums we are pursue perfection

It only happens when it sits for 24 or more hours. Driving it today no issues at all after start up.

Super confused :-/ it's almost like a long crank that's why I keep going battery...

Thanks for the idea of the tender Jeremy. I'll take a deep look this weekend. Might just do coils and plugs again as I use fcp euros warrenty program if I run out of ideas.

[jv004]

I heard somewhere if you turn the car on first with out stepping on brake then starting engine helps reduce that cranking from your video on cold start. I guess it primes the fuel through the injectors or gets the injectors ready. Reason why you don't get the issue on second engine start. But don't know if that's true, but worth a try to see if anything changes.

[thejeremyman9]

Originally Posted by jv004

I heard somewhere if you turn the car on first with out stepping on brake then starting engine helps reduce that cranking from your video on cold start. I guess it primes the fuel through the injectors or gets the injectors ready. Reason why you don't get the issue on second engine start. But don't know if that's true, but worth a try to see if anything changes.

I thought Kies mentioned in the HPFP video that the LPFP primes when you hit the unlock button. There is always a noise that sounds like that's what i could be... need to fact check that though.

[Orion4]

It doesn't sound battery-related. If concerned about the battery, go to Batteries Plus or an Auto parts store and have them test the battery, including a load test. Normally free and will give some insight it the health of the battery.

[TheJungatron]

Originally Posted by jv004

I heard somewhere if you turn the car on first with out stepping on brake then starting engine helps reduce that cranking from your video on cold start. I guess it primes the fuel through the injectors or gets the injectors ready. Reason why you don't get the issue on second engine start. But don't know if that's true, but worth a try to see if anything changes.

Interesting...

I'll have to try that tomorrow.

Might run over to and autopart store to test the load of the battery just to be sure.

[TheJungatron]

Here's another take on it. Running out of ideas. Battery came back fine with volts never dropping below 10.50 on crank.

[Korvo]

Did you delete cold start with BM3?

[TheJungatron]

Originally Posted by Korvo

Did you delete cold start with BM3?

No, Cold start is still on and so is the GTS roar from BM3. I turned off BM3 GTS and it did nothing a week ago.

I might try cold start off and report back

[thejeremyman9]

Originally Posted by Jungatron

Here's another take on it. Running out of ideas. Battery came back fine with volts never dropping below 10.50 on crank.

I just watched this a few times... what exactly is the concern? How it hesitates for a second after starting before raising the rpm?

[exE36M3]

So here's what I get from time to time....

1. Start car (generally if it's been sitting for a couple days or more) OR there's been a drastic weather change (like crazy heat or cold).

2. Car will rev higher when started, then drop for a second, like it wants to die... then catch itself.

3. Then after about 10 seconds... the idle will drop to normal and it's good to drive.

Yes?

[Korvo]

Originally Posted by Jungatron

No, Cold start is still on and so is the GTS roar from BM3. I turned off BM3 GTS and it did nothing a week ago.

I might try cold start off and report back

I had this issue with BM3 cold start disabled, but it was random. Someone recently mentioned that running Techron fixed an issue like this.

Worth the $4!