Hi Everyone,

I'm new to this channel but i need some help if anyone has experienced what I am going through. I have 2010 535i xdrive M-Sport with 71k miles on it. Car runs and drives absolutely fine except for one issue. When I go to put gas in the car, upon starting the car, it shakes and the check engine light comes on it reads that there is a lean mixture. I have done a smoke test and found that my valve cover had a crack and both turbocharger blow off valves were leaking. I have changed all of that and smoked tested the car again and it has no issues. I cleared the code and test drove the car it was fine but as soon as i went to the gas station and put $10 of gas the same issue would come back. This only happens when i put gas in the car. To be sure that I wasn't going crazy I had a BMW dealer check it out they can confirm that there is no other leaks in the system and all sensors are working fine. I asked them if they can fix it they told me they don't even know what is going and BMW engineering got involved and said to try and replace the igniters if that doesn't work we cant help. They have inspected them and said they don't seem to be bad because everything else in the car is working fine but they arent 100% sure. I have checked the gas cap to make sure its good (it is). I don't fill up my car when the engine is running. Personally i don't think it is the igniters because the car would be running rough, i feel it may be a sensor but idk. Everything in the car is perfect except for when i put gas and i only put 91 and 93 in it. The only code i am getting is the system is too lean.

Any information will help!! I haven't driven this car in about a month trying to resolve it. :'(

 

Does it run better only once fuel gets to a certain level? What if you only filled to 1/2 or 3/4 of a tank, same issue? What if you filled up most of the way, came home and used a can to fill it up and then let it sit overnight before starting? What if you try starting with the gas cap off? These are all things I would try to isolate the issue. I’m guessing something with pressure in the tank is affecting the fuel pump.

 

it runs the same no matter what the fuel level is. even if the car stays over night the issue is still there. When I serviced the car and cleared the code it was normal like nothing is wrong until i put gas in it then the shaking begins followed by the light. The car then shakes until i fixed something else and clear the code but it will come back when i put gas.

I agree i feel like it has to do with pressure because it is only when fuel enters the tank. I made assumptions it was a purge valve or an evap valve but i have no clue.

 

On the e60 the fuel pressure regulator is under the back seat gas tank (on the driver's side).

The pressure regulator is embedded in the fuel filter assembly and gas level sending gauge.

When was the last time that unit was changed?

 

Update:

So i checked with my service center and they changed my igniters. My fault was reading lean in bank 2 so they swapped bank igniters and the fault followed. I have changed them and the car is now working great. BTW lesson learned is you can change only one igniter, if you change 1 you have to change the rest of them in the same bank.

 

Thanks for letting us know your solution.

 

Still, this doesn't explain why your problem only came up after a refueling. How does the service centre explain that?

 

The question was raised, "this doesn't explain why your problem only came up after a refueling. How does the service centre explain that?"

I was reading a e60 post for a similar issue. The vehicle would throw a code after refueling or having a certain level of gas in the tank.

The problem ended up being the purge valve assembly above the right rear tire (remove the wheel lining to get to the purge valve). There is a small motor that recaptures fuel vapors regarding the charcoal canister. That motor went bad and was triggering codes.

 

That explains the alarm, but doesn't explain why the OP had problems only after refueling. Coincidence? Or, since he replaced the "igniters" and that solved the problem, he hadn't noticed that the problem was there on other occasions when he hadn't just refueled, but only associated it with the alarm. The "igniters" and fuel tank level etc. have no relationship.