[radeohedca]

2013 320i
When I start my car on a cold morning it will run for about 30 or 40 seconds then stumble... sometime it will stall, other times it will recover. If it stalls then I can restart it and all is well. It's acting as if there's an issue with the MAF sensor but it's not throwing codes. Like starting in open loop then crashing when it goes to closed loop. Anyone else seen this or have any suggestions ?
Thanks.

[cfm56d7b]

It's unusual that codes are not thrown. I suggest to check again. What code scanner are you using?

Starting with a caveat that remote diagnostics are rarely perfect, these are the items worth taking a look at:

- Fuel delivery / mixture (LPFP, HPFP, injectors): again - codes will be thrown if something is outside of the specifications
- Misfire in one of the cylinders: codes will be thrown ...

[radeohedca]

I'm using a BlueDriver Bluetooth scanner.

[paulymu]

I have a 2016 340, and mines does something similar and i hate it. The worse its been was when i got the drivetrain malfunction and had to replace the tank vent valve. It got rid of the drivetrain malfunction but the issue came back a while later. Not sure what it is at this point or what to do. I don't have any check engine light or any codes (last time i checked). I also use the blue driver scan tool. Mite also look into replacing my leak detection module because when i first noticed the issue an i used the BlueDriver it said something about system too lean/small leak detected. I tried tightening gas cap and all but code still stayed for a while until i replaced the vent valve and hasn't returned since. Any suggestions before replacing leak detection module?

[thejeremyman9]

Does this scanner detect both active and shadow codes?

Are you guys stock, or running any mods, specifically an intake?

How is your battery SOC? Are you starting in low temps, take frequent short trips, drive infrequently, or any combination of the 3?

How many miles on car/plugs/injectors?

[Billfitz]

It's not the battery. Once the engine starts its job is done. From that point on what keeps the engine running is fuel, air and ignition. The places to start looking at are the fuel pumps, injectors, air filter and plugs. You should be getting codes, lots of them if the car actually stalls.

Any suggestions before replacing leak detection module?

Does the code say no connection with DME? I had that, it turned out to be wiring chewed by a mouse.

[MHF30]

I've had something similar happen when backing out the driveway after a cold start. The car just dies when I get to the end of the driveway and then I have to start it again. Happened a couple of times a couple years ago but hasn't happened since.

[thejeremyman9]

Originally Posted by Billfitz

It's not the battery. Once the engine starts its job is done. From that point on what keeps the engine running is fuel, air and ignition. The places to start looking at are the fuel pumps, injectors, air filter and plugs. You should be getting codes, lots of them if the car actually stalls.
Does the code say no connection with DME? I had that, it turned out to be wiring chewed by a mouse.

IIRC there was another person in the N55 section that had an issue where the RPM would dip very low on a cold start - as in it would fire, go up to ~1500, then dip to ~400-500, then pick back up again. He posted a log and you could see his voltage drop during and immediately after cranking. It was the battery. So I think the battery can be a factor during and immediate after a cold start before sufficient power is delivered by the engine. Not saying its the issue here, but just something to consider.

Other people have had luck running techron complete fuel system cleaner, but that was usually for rough idle and not a complete stall.

[pshovest]

Originally Posted by radeohedca

....2013 320i.... Like starting in open loop then crashing when it goes to closed loop........

Sure sounds like a fuel problem. I would set scanner up to see live data for fuel trims (STFT, LTFT, additive, multiplicative) w/ignition on before starting. Start engine and note what happens to fuel trims when engine begins to stumble. If they go excessively positive, you've got a lean condition. Continue to watch as engine warms up. What are they at operating temp?

[paulymu]

The only code i remember is air fuel mixture too rich, and small leak detected. Can't remember the exact code though. I changed my plus at about 55k an im at 64k rite now. Didn't do injectors and not sure if previous owner changed it but i doubt it. No i don't get any dme code about the leak detection module. I was on noglutchgarage youtube channel and he was dealing with something similar and thats the fix he recommended.

[bloodline129]

Originally Posted by thejeremyman9

IIRC there was another person in the N55 section that had an issue where the RPM would dip very low on a cold start - as in it would fire, go up to ~1500, then dip to ~400-500, then pick back up again. He posted a log and you could see his voltage drop during and immediately after cranking. It was the battery. So I think the battery can be a factor during and immediate after a cold start before sufficient power is delivered by the engine. Not saying its the issue here, but just something to consider.

Other people have had luck running techron complete fuel system cleaner, but that was usually for rough idle and not a complete stall.

That was me! Lol, haven't replaced the battery yet unfortunately. Still experiencing same issue

Battery should be done in next few weeks I hope and I'll report back

[radeohedca]

Originally Posted by thejeremyman9

IIRC there was another person in the N55 section that had an issue where the RPM would dip very low on a cold start - as in it would fire, go up to ~1500, then dip to ~400-500, then pick back up again. He posted a log and you could see his voltage drop during and immediately after cranking. It was the battery. So I think the battery can be a factor during and immediate after a cold start before sufficient power is delivered by the engine. Not saying its the issue here, but just something to consider.

Other people have had luck running techron complete fuel system cleaner, but that was usually for rough idle and not a complete stall.

You guys may be on to something. I do have battery codes when I perform a scan and a couple of times when it was bitterly cold I had an error message on the CIC. It's the original 8 year old BMW battery... I can tell that it's never been changed. I'm going to replace it in the next day or two and see if the cold start RPM drop gets resolved. Thanks !

[Billfitz]

Originally Posted by thejeremyman9

IIRC there was another person in the N55 section that had an issue where the RPM would dip very low on a cold start - as in it would fire, go up to ~1500, then dip to ~400-500, then pick back up again. He posted a log and you could see his voltage drop during and immediately after cranking. It was the battery. So I think the battery can be a factor during and immediate after a cold start before sufficient power is delivered by the engine.

It's not impossible. If the battery is severely low the power management system might be sending too much juice from the alternator to the battery upon starting, causing current starvation in the fuel and/or ignition system. But...many a year ago when I worked for Ford corporate our office took possession of a bankrupt dealer's inventory. We went to his lot to drive the cars to a secure location, but the batteries were all dead, so dead that when we tried to jump start them from a company car the dead batteries sucked up all the juice and they still wouldn't start. I was the only one of the group with mechanic experience, and I knew that if we disconnected the batteries the cars would start with a jump and run without a battery. After the cars were running we hooked the batteries up again and were good to go. I got a nice bonus that week, because otherwise they'd have had to bring in a fleet of flatbeds to haul those fifty odd cars.