HELP - Filled up today and my car immediately went into limp mode *UPDATE #2 11/24*

[RoofusM3]

08 E90 M3. Car is meticulously cared for and has been running absolutely fine. Filled up at the usual Exxon today with 93 (I was very low, read less than 9 miles on the tank) and got no more than 300yds from the station and the car flipped out. I assume what happend was this cars version of limp mode.

The adjustable redline dropped to 4k rpm max. Dash alerts read service engine soon and something about increased emissions. Stuck the code reader on it and it codes for the following:

P0300 Random/Multiple Cylinder Misfire Detected
P0301, P0303 - P0308 which are codes for each cylinder for a misfire; i.e. every cylinder but #2 for whatever reason.

Cleared the codes to see if it was a fluke. Drove 200yds and same thing happened. Same codes, dash lights, and limp mode.

I got it home (and obviously your mind goes to the worst thing) so I pulled all the plugs for the left bank to make sure the plugs looked fine (changed back in June of this year) and there was no oil on the plugs or in the cylinders. Plugs were all fine, cylinders as clean as a whistle.

Everything looks in good order, and I'm hard pressed to believe 7 coil packs died simultaneously.

I'm assuming at this point the "93 octane" gas I received was absolutely not 93 octane. And I have no idea how to deal with that.

1) Any other possible malfunctions to clear off the list?
2) If not, (or after checked off) what do I do? I've had bad gas before in high performance engines and turbo engines that you couldn't push and just had to drive super civil till the tank emptied, but I've never had a car that got gas so bad that I couldn't even drive 20mph at low rpm without it freaking out like this. If this is faulty gas, this car is extremely sensitive to it.

Any advice is appreciated!

*UPDATE IN POST #18*
*UPDATE #2 IN POST #21*

[Helmsman]

Originally Posted by RoofusM3

08 E90 M3. Car is meticulously cared for and has been running absolutely fine. Filled up at the usual Exxon today with 93 (I was very low, read less than 9 miles on the tank) and got no more than 300yds from the station and the car flipped out. I assume what happend was this cars version of limp mode.

The adjustable redline dropped to 4k rpm max. Dash alerts read service engine soon and something about increased emissions. Stuck the code reader on it and it codes for the following:

P0300 Random/Multiple Cylinder Misfire Detected
P0301, P0303 - P0308 which are codes for each cylinder for a misfire; i.e. every cylinder but #2 for whatever reason.

Cleared the codes to see if it was a fluke. Drove 200yds and same thing happened. Same codes, dash lights, and limp mode.

I got it home (and obviously your mind goes to the worst thing) so I pulled all the plugs for the left bank to make sure the plugs looked fine (changed back in June of this year) and there was no oil on the plugs or in the cylinders. Plugs were all fine, cylinders as clean as a whistle.

Everything looks in good order, and I'm hard pressed to believe 7 coil packs died simultaneously.

I'm assuming at this point the "93 octane" gas I received was absolutely not 93 octane. And I have no idea how to deal with that.

1) Any other possible malfunctions to clear off the list?
2) If not, (or after checked off) what do I do? I've had bad gas before in high performance engines and turbo engines that you couldn't push and just had to drive super civil till the tank emptied, but I've never had a car that got gas so bad that I couldn't even drive 20mph at low rpm without it freaking out like this. If this is faulty gas, this car is extremely sensitive to it.

Any advice is appreciated!

Like you say the petrol may not be what you bought. Happened with my previous car (E60 550i), stopped soon as I left the station. Turned out diesel and gas was poored in wrong tanks so I got diesel. Got it cleaned out and was fine. It was much worse for the diesel cars that got the 98oct...

[SAMM3Y]

You might have sucked up whatever sediment was in your "really low" tank. Maybe gummed up the filter? Just an idea

[cclinard1]

Had this happen when the gas cap didn't seal correctly. Also, others have had the same issue when the gas cap seal is bad. Simple, but have you tried to just take the cap off and make sure it's sealed good?

[SkiFly01]

I would lean not towards anything mechanical if it happened that quickly and runs fine with codes cleared. I would say it's the fuel, just run that tank down and get a fresh tank in. Even with 87 oct it will run without throwing codes, it will pull a crap load of timing for safety but it will operate without issue. Sounds like you have either a lot more ethanol content or even water in your tank.

[RoofusM3]

It would seem very odd to me for the throttle actuators to go out that suddenly. But is it possible to have a TBA failure with only misfire codes and no TBA code?

[RoofusM3]

Originally Posted by cclinard1

Had this happen when the gas cap didn't seal correctly. Also, others have had the same issue when the gas cap seal is bad. Simple, but have you tried to just take the cap off and make sure it's sealed good?

I have not. I will check. I did get some gas cap alerts over the summer that also occasionally popped a code for some sort of evaporator if I remember correctly. I replaced the gas cap with a new one and those codes ceased. But since you mentioned it, I'm flagging it.

[BeaterM3]

My LPFP shit itself right after I filled my gas tank on my 335i a few months ago. Smelled a long wiff of gas along with it as well. Then limp mode. The pump was still functioning but barely.

[RoofusM3]

Originally Posted by revengeismine

My LPFP shit itself right after I filled my gas tank on my 335i a few months ago. Smelled a long wiff of gas along with it as well. Then limp mode. The pump was still functioning but barely.

Interesting. Doing some reading I’m seeing that if the LPFP dies the car will not run, but if the HPFP goes out the car will show misfires and go into limp mode.

[RoofusM3]

Let the car sit for two days. Started it up this morning with no issues whatsoever. Drove to work, drove home, no problem.

On one occasion when turning the car off, a message saying "battery at low charge" or something along those lines popped up.

Later in the day, I drove to the store and it drove completely fine. But when I cranked the car it immediately went into limp mode. I shut the car off and restarted it about 5sec later and it was completely fine and drove normally back home.

Now leaning toward it having nothing to do with the gas. Maybe an electrical issue screwing with fuel pressure and that's causing the misfires? Kinda stumped on this one.

[drrust]

Either your battery or alternator is bad. My alternator died and the DCT wouldn't stay in gear.

[timothy2001]

I recall reading about a fuel breather valve issue that can cause problems and it's very elusive. Try doing on search on that and see if it describes anything close to what your are experiencing.

[xander_g]

Are you catless? If so, it could be an O2 sensor. I had similar symptoms.

[tpak1122]

switch out all your spark plugs. If same codes, and you can't narrow the cylinder, you might have to buy 1 new coil pack and switch them around the cylinders to see if one might be bad. or just buy 8 new ones.

[wfdeacon88]

Originally Posted by RoofusM3

Let the car sit for two days. Started it up this morning with no issues whatsoever. Drove to work, drove home, no problem.

On one occasion when turning the car off, a message saying "battery at low charge" or something along those lines popped up.

Later in the day, I drove to the store and it drove completely fine. But when I cranked the car it immediately went into limp mode. I shut the car off and restarted it about 5sec later and it was completely fine and drove normally back home.

Now leaning toward it having nothing to do with the gas. Maybe an electrical issue screwing with fuel pressure and that's causing the misfires? Kinda stumped on this one.

I'd get the codes and look for alternator issues. Mine is on the way out and I'm about to have it replaced.. different symptoms, but could be that yours is further gone than mine.

[RoofusM3]

Originally Posted by xander_g

Are you catless? If so, it could be an O2 sensor. I had similar symptoms.

No. Car is stock sans K&N stock replacement filter and H&R springs.

Originally Posted by tpak1122

switch out all your spark plugs. If same codes, and you can't narrow the cylinder, you might have to buy 1 new coil pack and switch them around the cylinders to see if one might be bad. or just buy 8 new ones.

Replaced all the plugs in June and less than 1,500m since. Pulled the plugs on left bank (passenger) and they all looked fine.

I’m away this week for work. Thinking I need to get the battery tested when I get back first to make sure I don’t have an electrical issue being caused by the battery or alternator.

[nick3753]

Originally Posted by timothy2001

I recall reading about a fuel breather valve issue that can cause problems and it's very elusive. Try doing on search on that and see if it describes anything close to what your are experiencing.

Fuel tank breather issue will cause the car to stall after a fill up however it will not cause the car to go into limp mode (from my experience and past research).

[RoofusM3]

UPDATE 10/28

So in review, after the first few times of limp mode mentioned before I never went into limp mode again from about 3/4 tank until empty until last night.

Last night I filled up again (at a different station). I cranked the car and sat idle for a few minutes. After maybe 2 minutes the rpm needle started bouncing like it was struggling not to choke out and then the car went into limp mode. I turned off the car and cranked it again and it was fine.

I'm also getting "tighten the gas cap" messages AND still getting low battery messages when I turn the car off.

I feel like I'm dealing with multiple problems:

1) Stalling/Limp Mode after fill up > Fuel tank breather valve?
2) Low power warning > Bad battery &/or alternator?
3) Gas cap warning > I just replaced the gas cap with a brand new cap a few months back. Not sure how to diagnose.

I bought a fuel tank breather valve this week, so I can get that swapped in. I tried to get the battery/alternator checked, but the tester at Autozone wouldn't work on my car, so I'll need to go somewhere else. But I have no idea what's going on with the gas cap.

I'll try to knock these out one by one and keep reporting back.

[New2Roundel]

How old is the battery? After about 5 yrs, I'd just put in a new one. Although I didn't get a warning about it, at about the 5 year mark, my car wouldn't even turn over one morning. Replaced the battery and all was good.

If you're doing the breather, why not also try another gas cap? They're cheap enough.

[RoofusM3]

Originally Posted by New2Roundel

How old is the battery? After about 5 yrs, I'd just put in a new one. Although I didn't get a warning about it, at about the 5 year mark, my car wouldn't even turn over one morning. Replaced the battery and all was good.

If you're doing the breather, why not also try another gas cap? They're cheap enough.

I assumed the battery was the original battery. If it was replaced it was replaced with a BMW brand.

I put a new battery in tonight, same specs as what was in it. AGM 900 90. We'll see if that clears up some of these gremlins. Did a battery reset with Bimmerlink. Fingers crossed that really works as it didn't show a previous mileage (app only reports in Km) of a previous reset. I guess I can try to cycle the app and see if it shows the current mileage of my reset tonight. Might have to switch the car setting to Km and see if it'll read it then.

I'll do breather tomorrow. I'd like to see if that clears up the gas cap warning first before ordering another. I got an oem replacement part. Would seems weird that a gas cap would be a lemon, but I guess anything could happen.

But if somewhere between replacing the battery and the breather solves the misfires and limp mode then I've solved the big problem. Will just need to finally figure out why I can't get my bluetooth to work after that...

[RoofusM3]

I believe I have been dealing with 3 issues simultaneously.

1) After replacing the battery the low battery and weird electrical issues have totally disappeared. So that's a win.

2) I replaced the low pressure fuel sensor and the fuel breather valve last weekend. This seems to have fixed the idle stutter issues (bouncing rpm needle at idle) and the car stalling after a fill up. So that's a win.

3) The remaining issue relates to the "tighten gas cap" problem I was experiencing and seems to correspond with a code that occasionally will pop up with it: P0442 Evaporative Emission System Leak Detected. I am still getting the tighten gas cap alerts right after a fill up and if I don't turn off the car rather quickly and take it off and put it back on then I will occasionally get the limp mode.

I have also noted a strong smell of gas vapors (more than normal) when I remove the gas cap. (Remember I have a brand new gas cap).

So I'm thinking this probably indicates I've got a faulty charcoal filter or a leak in one of the lines that goes to it. Thinking it may be best to have my mechanic run a leak test considering those parts are pretty pricey.

[RoofusM3]

*UPDATE 12/18*

After a few weeks here with the new fuel breather valve and new low-pressure things are still doing better. But I'm still getting a "loose gas cap warning" and a P0442 - "Evaporative Emission System Leak Detected (Small Leak)" code.

On occasion, on a cold start, I have also gotten a DSC failure dropping the car into limp mode and a P152D - "Idle-Speed Control Valve Monitoring Incorrect Actual Value (Bank 1)" code.


I'm wondering if the issue in my first paragraph is related to the charcoal filter or a leaking gas vapor line. And the issue in the second graph is unrelated and maybe a sign of failing throttle-bodies.