Help! 2009 BMW 328xi coupe problem starting

[lastnerve]

2009 BMW 328xi coupe. Approx 62,000 miles. Problem: My car has a problem starting when I take it on short trips. NOT ALWAYS, but frequently. For instance, if I drive 10 minutes, shut it off, run in a store for a soda, when I try to restart -it will crank over but not start. When I do finally get it started, it runs REALLY bad stuttering and stammering until I shut it off and let it sit. On trips where the car sits for longer periods, it will restart with no problem. Otherwise the car runs great, I mean really great! I have had the same problem since I bought the car two years ago. The fuel pump went bad and I had it replaced. Same problem still exists. I had the entire valve cover assembly replaced because of some part that is integrated. Same problem still exists. Recently, I had the MAF changed. Same problem still exists. Check engine light comes right back on within 5 miles of clearing it and throws a Bank 1 & 2 code each time. One last observation is that sometimes when I shut it off after longer trips, I can hear a constant humming noise from the back of the car like the gas tank is purging. Air maybe? That all being said, it definitely seems like its sucking air into the fuel system, but mechanics have been ALL over the car and can't figure out where or how. Smoke tested twice -NO leaks detected. Would a bad gas cap or purge valve o-ring cause any of these problems for me? could it suck enough air that way to cause these problems? I know that is a major reach, but at this point.......ANY advice? Thanks in advance!

[shogun]

Moved from cars for sale to 3 series subforum

[relative4]

For sale is right. OP just did a piss poor job of listing it.

Are you gonna eat that?

[relative4]

What codes are you getting? What are your fuel trims at idle?

Are you gonna eat that?

[154e90]

It sounds like a crank sensor gap or performance issue to me. They typically fail when hot. Have someone with an oscilloscope check cam and crank signals when the car is hot and won't restart. There's no other way to find this issue if that's what it is.

They stay cool due to airflow when the car moves and heat soak when you turn the car off. This expands some part of the pcb and severs a connection internally. You have to wait for it to fully cool down for the pcb to shrink back and make the connection again.

I highly doubt a purge solenoid is causing your no start.

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[3onthetree]

Hi. I think it sounds like computer. I’ve heard this one before. The heat and expansion from running the engine messes with a bad computer.


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[3onthetree]

Oh yeah. Just like guy, more eloquently said before me. Anyway two votes


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[JDStrickland]

2009 BMW 328xi coupe. Approx 62,000 miles. Problem: My car has a problem starting when I take it on short trips. NOT ALWAYS, but frequently. For instance, if I drive 10 minutes, shut it off, run in a store for a soda, when I try to restart -it will crank over but not start. When I do finally get it started, it runs REALLY bad stuttering and stammering until I shut it off and let it sit. On trips where the car sits for longer periods, it will restart with no problem. Otherwise the car runs great, I mean really great! I have had the same problem since I bought the car two years ago. The fuel pump went bad and I had it replaced. Same problem still exists. I had the entire valve cover assembly replaced because of some part that is integrated. Same problem still exists. Recently, I had the MAF changed. Same problem still exists. Check engine light comes right back on within 5 miles of clearing it and throws a Bank 1 & 2 code each time. One last observation is that sometimes when I shut it off after longer trips, I can hear a constant humming noise from the back of the car like the gas tank is purging. Air maybe? That all being said, it definitely seems like its sucking air into the fuel system, but mechanics have been ALL over the car and can't figure out where or how. Smoke tested twice -NO leaks detected. Would a bad gas cap or purge valve o-ring cause any of these problems for me? could it suck enough air that way to cause these problems? I know that is a major reach, but at this point.......ANY advice? Thanks in advance!

???

You said it has codes for Bank 1 & Bank 2, but there are dozens of codes that can be for Bank 1 & Bank 2. What are the codes you are getting? Also, you are treading on things where it matters to know if the engine is the N51 or N52. Go to www.realoem.com and enter the last 7 digits of your VIN (these digits will be something like, AB12345), realoem will throw up a page that tells you the engine designation. The N51 is a SULEV motor (Super Ultra Low Emissions Vehicle) that has stuff that makes some of the emissions stuff different than the standard (N52) engine.

Somebody is selling you parts that very likely are not needed, this is one of those times when the mechanic needs extra money that month to make his yacht payment, and you are the next guy that walks in the door. You are conflating all sorts of different things that have nothing to do with one another, and you are asking if the gas cap or purge valve can cause these problems, but you don't tell us what "these problems," are. I see the part about sputtering and stammering, but these can arise from an engine that is running very slowly because of the battery, the computer is trying to keep it running, but the motor is going so slowly that the computer can't make it run smoothly.

My first thought when I started reading was that you have a weak battery. I see a slow start when cold, then you drive down the block and park, making the next start slow, maybe slower, and you get the spurts and sputters. Then you drive while and get the battery charged up and all is well for a while. But, you NEED to tell us the codes, Pnnnn is the preferred format.