[TheJungatron]

Originally Posted by thejeremyman9

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

The issues is the strange hesitation, It just doesn't feel right. The video doesn't do it justice. It sounds way strange in person.

Might just have to live with it until a real code shows up or I might just replace the fuel rail pressure sensor when I do my spark plug and coils again soon. Thanks FCP Euro for the lifetime warranty parts.

Originally Posted by Korvo

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!

Tried Techron this weekend. Ran almost a full tank of gas though the car and it started ok this AM.

I also tested the battery with Bimmerlink and it stated 74%... not sure if that mean anything.

Thanks for all the ideas gang :-)

[TheJungatron]

Ok so finally got treatment #2 of techron though the system and I will say its running a lot better on startup, I really haven't seen the delayed startup in about a week or more at this point even when letting it sit for days.

Maybe it was dirty fuel sensors, injectors or something.

Thanks Gang :-)

[EvenKeel]

Check your PCV Valve

[Munchi435i]

Originally Posted by Korvo

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!

Which techron did you use? The grey bottle or black one. I believe the black one is a concentrated mix.

Looking to do this since I'm getting similar issues. But this only happens when I'm running a ethanol mix. Rarely does this happen when I'm running straight pump 93.

How many bottles or cycles are recommended, 2? 4?

[thejeremyman9]

Originally Posted by Munchi435i

Which techron did you use? The grey bottle or black one. I believe the black one is a concentrated mix.

Looking to do this since I'm getting similar issues. But this only happens when I'm running a ethanol mix. Rarely does this happen when I'm running straight pump 93.

How many bottles or cycles are recommended, 2? 4?

You want the "complete fuel system cleaner" one, not the injector cleaner or whatever the other one is as it has a lower concentration. See attached photo below.

I was doing this once a year before oil change but given the success so many others are having i am going to step it up to twice a year, especially since i am consistently running E30 and never pump gas only. The other guy said he did 4 in a row to fix existing issues. That might be overkill if you are just doing it as preventatively but i think 2 bottles in a row might not hurt.

[1KWIKBMR]

Originally Posted by 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?

My car just started doing this. The weather turned cooler and it does this some mornings when I crank it for the first time of the day. It doesn't usually happen any other time, only the first start of the day.

[TheJungatron]

welp, I have still be chasing this issue. I let the car sit for 3 days and it sounded like hell starting up.

It cranks and stumbles then turns over. I let it run for a minute, turn it off then restart the car and it works flawlessly.

I'm just running out of patience with this thing. It doesn't show any codes so I can't see what the heck is starting to fail.

[TheJungatron]

Issue is still persistent... not going away. If the car sits and doesn't get run every day it feel like it's not going to start. it jumps all over the place on first start. Going to add my BM3 logs.
https://www.bootmod3.net/log?id=5fbf...0b434a0a882a4a

[about94ninjas]

Try flashing the car back to stock and seeing what happens. I've heard a few other people having issues with cold starts on OTS maps, and I believe the consensus was that some fuel needs to be added during cold starts to make them smoother. It's nothing to worry about.

[TheJungatron]

Originally Posted by about94ninjas

Try flashing the car back to stock and seeing what happens. I've heard a few other people having issues with cold starts on OTS maps, and I believe the consensus was that some fuel needs to be added during cold starts to make them smoother. It's nothing to worry about.

Ok, Ill give it a shot and let it sit for a couple says. Any idea if BM3 will address it?

Thanks!

[TheJungatron]

update, I detuned the car and let it still. Its not starting as rough when it was left alone vs when tuned.. gunna let it sit for over 48 hours to see there's any change.

[rjd_F30]

For what it's worth,your videos look 100% normal to me. My car is not tuned (just intake and exhaust) and if it sits for more than 48 hours, there's a bit of unsteadiness in the high idle on cold start for a few seconds before it smooths out again. My old 328i did the same thing for years and it never became more of a problem than a minor annoyance every few startups after sitting. Just my .02, you may want to reach out to BM3 to see if they can smooth it out in the startup tune but I wouldn't be concerned that this is the result of a bigger underlying (or mechanical) issue.

[TheJungatron]

Originally Posted by rjd_F30

For what it's worth,your videos look 100% normal to me. My car is not tuned (just intake and exhaust) and if it sits for more than 48 hours, there's a bit of unsteadiness in the high idle on cold start for a few seconds before it smooths out again. My old 328i did the same thing for years and it never became more of a problem than a minor annoyance every few startups after sitting. Just my .02, you may want to reach out to BM3 to see if they can smooth it out in the startup tune but I wouldn't be concerned that this is the result of a bigger underlying (or mechanical) issue.

Thanks RJD,

It has sat for about 24 hours now, I'm going to let it got for another 24 then start it up and record it. Makes me think there is something going on with fuel pressure.... we will see tomorrow

[thejeremyman9]

Originally Posted by Jungatron

Thanks RJD,

It has sat for about 24 hours now, I'm going to let it got for another 24 then start it up and record it. Makes me think there is something going on with fuel pressure.... we will see tomorrow

I have also thought this looked normal since the beginning, but understand it can be different in person when you notice an anomaly. If you think there's a FP issues, you can log the startup.

[TheJungatron]

Originally Posted by thejeremyman9

I have also thought this looked normal since the beginning, but understand it can be different in person when you notice an anomaly. If you think there's a FP issues, you can log the startup.

Hey jeremy, the start up log is now on on post #1. I'm kinda lost. It's way more strange then the video looks too. hoping to see tomorrow if its just the tune being strange. Ill post another log tomorrow.

[thejeremyman9]

Originally Posted by Jungatron

Hey jeremy, the start up log is now on on post #1. I'm kinda lost. It's way more strange then the video looks too. hoping to see tomorrow if its just the tune being strange. Ill post another log tomorrow.

Took a quick look at the log. HPFP pressure picks up right away and doesnt really fall behind target. I don't notice anything unusual, but i also don't look at many startup logs.

[rjd_F30]

Originally Posted by Jungatron

Hey jeremy, the start up log is now on on post #1. I'm kinda lost. It's way more strange then the video looks too. hoping to see tomorrow if its just the tune being strange. Ill post another log tomorrow.

As has been said, there's certainly something to be said for abnormalities being easier to pick up in person than on video, but with the normal looking logs and videos, I'm stumped brother :/

[TheJungatron]

Originally Posted by rjd_F30

As has been said, there's certainly something to be said for abnormalities being easier to pick up in person than on video, but with the normal looking logs and videos, I'm stumped brother :/

Thanks guys for the help. After detuning and letting it sit for 48 hours, it started like a normal start... so I retuned it to stage 1 and let it sit and now it seems to be ok?.... I don't get it.

Ill update if I ever figure out anything.

happy holiday's :-)

[thejeremyman9]

Originally Posted by Jungatron

Thanks guys for the help. After detuning and letting it sit for 48 hours, it started like a normal start... so I retuned it to stage 1 and let it sit and now it seems to be ok?.... I don't get it.

Ill update if I ever figure out anything.

happy holiday's :-)

Could have been something with adaptations. Not sure if you did that previously, but if it comes back, you could try reseting adapations and see if it makes a difference.

I just started my car for the first time in over 2 weeks. Has been sitting with E30 in the tank that whole time. Started right up no issues even though i had my doubts for a long crank or initial rough idle lol

[TheJungatron]

Originally Posted by thejeremyman9

Could have been something with adaptations. Not sure if you did that previously, but if it comes back, you could try reseting adapations and see if it makes a difference.

I just started my car for the first time in over 2 weeks. Has been sitting with E30 in the tank that whole time. Started right up no issues even though i had my doubts for a long crank or initial rough idle lol

Yeah, I reset adaptation anytime I mess with the tune. I just don't get it. Cars been a dream other the that start up weirdness. Glad it's gone. I'm wondering if it was a tune issue all along... oh well


I'll keep updating if anything changes.

[TheJungatron]

So latest update. Let the car sit for 48 hours In the cold. Started up just fine. I'm thinking it was a tune issue.

Once I reverted back to stock and rest adaptations, I let it sit for a day then retuned the car and reset adaptations again it's worked solid.

[Bmwerspeed123]

Originally Posted by Jungatron

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

_________________________________________________
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

Do you still have this issue? I have the same peoblem but I do not have a tune..