E46Fanatics

E46Fanatics (http://forum.e46fanatics.com/index.php)
-   Driveline, Engine & DME Tuning (http://forum.e46fanatics.com/forumdisplay.php?f=98)
-   -   Dropping a cylinder when the car reaches 1/4 tank of gas (http://forum.e46fanatics.com/showthread.php?t=745097)

aj330ci 03-01-2010 01:53 PM

Dropping a cylinder when the car reaches 1/4 tank of gas
 
Ok, this is a really strange thing that has been happening to my car for the past few months, and just happened last night, so I'm kind of worried.

I drive a 2004 BMW M3.

When my car reaches right around 1/4 tank of gas left, it feels like the car drops a cylinder. Same feeling as like a coil pack going out. The car loses basically all acceleration, and if you try to get it moving, it just spits, sputters, and dies on you.

After I go to the gas station, fill the car up with gas, and let it run for a little while, it works just fine again. I did some reading on the Internet, and I know how the car is behaving is like a coil pack going out, but I doubt that's it since it only happens when the car reaches 1/4 tank of gas left.

I also know the gas gauge isn't wrong because when I stopped and filled it up, I put 12 gallons in on a 16 gallon tank, with the 4 gallons being the 1/4 tank that was left.

Does anybody have any ideas what could be going wrong with the car? The solution right now is to just keep it above 1/2 tank of gas at all times, but that's just until I can get it to the shop.

Thanks for any and all help!

Justin@SharkInjectorDirect 03-01-2010 02:13 PM

It sounds like it could be a failing fuel pump.

As the fuel level gets lower, it has to work harder to pump the fuel to the engine bay.

Think of it this way. Lets say you were on a 5 story building and there was a bucket of water on the ground level. Imagine trying to suck the water up to your level thru a straw. Now imagine the bucket of water was 6" below your mouth. Much less effort is needed.

ChasCan 03-01-2010 02:16 PM

Maybe something simpler? Fuel filter?

aj330ci 03-01-2010 02:22 PM

Quote:

Originally Posted by Justin@SharkInjectorDirect (Post 11397325)
It sounds like it could be a failing fuel pump.

As the fuel level gets lower, it has to work harder to pump the fuel to the engine bay.

Think of it this way. Lets say you were on a 5 story building and there was a bucket of water on the ground level. Imagine trying to suck the water up to your level thru a straw. Now imagine the bucket of water was 6" below your mouth. Much less effort is needed.

I was kind of thinking fuel pump as well. Guess all I can do is drive the 2 hours to the dealership, and let them take a look at it. Oh the joys of BMW maintenance, lol!

TKC 03-01-2010 02:24 PM

This might help you. :)

Good luck

http://forum.e46fanatics.com/showthr...highlight=fuel

aj330ci 03-01-2010 02:31 PM

Quote:

Originally Posted by TKC (Post 11397377)

Wow AMAZING write-up! Thanks! :bow:

Justin@SharkInjectorDirect 03-01-2010 06:42 PM

Quote:

Originally Posted by ChasCan (Post 11397342)
Maybe something simpler? Fuel filter?

A fuel filter would most likely exibit issues all the time. It would not really be dependant on the fuel level.

But, it never hurts to change the fuel filter.


All times are GMT -5. The time now is 09:57 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use