Ricapar

It's been happening on a constant basis now. I regularly fill the tank when I'm reaching the 1/4 mark. I turn off the engine, fill 'er up, and go to start the car again. In the past, it's been fine.

However, recently... it's just been refusing to start. Engine will crank.. and then die. I have to do that a few times, giving it some gas in order for it to rev up properly and stay on.

I had some codes that were throwing a Service Engine Soon light.. those codes were also accompanied by an iDrive warning to tighten the gas cap. Upon my inspection, I noticed the gas cap was hardly sealing. I'd turn it to the click and give it some extra force, but I'd then be able to unscrew the cap with little to no force. Tapping with my pinky was enough to remove it. I got a new gas cap, and the errors seem to have gone away. My hope was that the starting issue would too.... but nope.

Before continuing, here are the codes I had:



The 2A1A one was due to the gas cap. Last two times I checked for any stored codes, it had gone away. I believe the last one (2A15) was also due to the gas cap. The middle two (2A2F, 2A2E) I suspect were due to the failed start attempts after a re-fuel.

However.. the other day I re-fueled, it again had a lot of trouble starting. I get it going, drive for about 30 mins and pull into a rest stop. I pull codes.... and they are empty. I've always gotten the 2A2F and 2A2E ones after the failed starts.... so now I'm confused. I suppose they could have cleared themselves during the drive, but that seems like a short amount of time to clear a code.



Does anyone have any ideas on where to start looking deeper into this?

Again... it only happens when re-fueling. Gas cap has already been replaced. Fixed the "tighten gas cap" warning, but the starting issue is still there.

Car is a 2007 525xi, N52 engine, 52k miles.

pcy

You will need to check fuel pressure during no-start condition.
Without other data, I'd guess the fuel pump is the cause.

pukka

+1

If its low I'd start by replacing the fuel filter assuming its external. Otherwise its on to the fuel pump.

luigi524td

My guess is it sounds like a fuel problem - but if it's a pump would your engine be starved for fuel when accelerating??. Supply (pump) or delivery (filter) - Is it possible you picked up a bad load of gas that has clogged the works up?

Do you fill up at the same station regularly? Have they reported a problem recently - I recall reading recently that some NJ gas stations had this problem - I don't recall specifically -- try Googling it! If that is the case and you can prove you bought gas there (credit card charges are adequate proof) I'd go back to them for the fix.

Ricapar

I'll research how to check the fuel pressure. E60's have the fuel filter and pump both inside the tank, so it's not exactly an easy job (at least compared to changing an oil filter, etc.)

That's what's puzzling me too. On any normal start (warm or cold), the engine starts just fine. When accelerating, no problems. This only happens after refueling.
As for the gas stations... I'm usually all over the place, and thus end up filling up in many different places. I avoid shady looking stations, and I've always put in 93 octane gas. As for getting bad gas.. I saw a few articles mentioning a large incident from 2008, but I haven't come across anything recent.

The only thing I can remember (which is when this all started, I think)... One time I was filling up and I didn't turn the engine off (forgot - I usually do). I was quite low on gas at that point (~20 miles left on the counter). Yeah, I know, I know... but I made it to a gas station at a service stop on the Parkway. As it's filling up, I feel the engine sputtering and the car shaking. Best way I could describe it was that it felt like it was about to stall and die, but it was kindof fighting for it's last turn. I immediately turned the car off at that point. I go to the turn the car on, and it behaves as I described in my first post. That was the first time that happened.

I've been through several re-fuels since then, at both local and not-so-local stations, and it's done it almost every time.

Qper2007

The purge (or tank vent) valve is probably sticking open. When you fill the car with fuel all the vapors go into the intake manifold and the car is effectively flooded. That's why you need to hit the gas pedal to get it to start. It lets more air in. This could cause all the faults. The 2A1A or the 2A15 faults. It sees the open purge valve as a leak in the tank vent system. The lean mixture faults are because when the valve is stuck open and there are no fuel vapors in the line it's like an air leak.

pcy

^ yes, very likely the purge valve is causing the problem.

turboawd

this guy knows what he's talking about

Ricapar

Wow, thanks! That's probably the best and most accurate recommendation I've gotten. I looked up some articles on BMW TIS about the Purge Valve that described how it worked... and the symptoms are pretty much dead on.

I'm still doing research as to how to go about replacing the valve.. Finding mixed results. I found a DIY from a guy that did it on an older M5, and it didn't look pleasant at all. But I also might've seen some people with 6-cylinder E60's claim they can do it fairly easily... so we'll see.

Indeed!