[ricoman1]

Hey guys...new member here,so tell me if I do anything wrong..LOL
OK..I have a 1994 540I that I purchased in 1995...I parked it at 70K for 10 years..long story.Anyway,I just drained the fuel and put new fuel pump in...wouldnt run right,but my mechanic found the wire on the sensor broke off,so he fixed that,and car runs like a dream....sorry I kept it on block all these years....I've logged about 1,000 miles on it..and been noticing the fuel gauge doesnt seem to like to go much past the halfway mark...at first didnt think much of it,but made sure I filled up when it hit halfway....SO...today,driving home,had a longer trip and figuring its a 21 gallon tank I'm good for 350 miles at least....well at 285 miles (which is like 13MPG),the car all of a sudden starts to sputter and slow down..run,sputter,slow down..and CHECK ENGINE light comes on...first thing I figure is Damn,gas gauge doesnt work and running out of gas...lucky for me gas station was 1/4 down road and I made it there..pulled in..car idles fine...so I fill it up,and on my way I go..drive the next 20 miles home fine....I've been using Regular grade gas since I got it back on road...So my question is,finally...could it of started because engine isnt liking the low grade...or is the fuel sensor/gauge really bad....13MPG is crazy since I remember getting like 20....When I fueled up,checked the engine..all was fine,oil OK,not overheating....Does the Check Engine light come on if you run out of fuel....there was no other warning and I thought the panel should of said LOW FUEL before getting to the point of empty...OR could it be some fuel sensor....? Hate to bring back to mechanic at $100 per hour for him to say,its OK,and shut the check engine light off....
HELP...& THANKS

 

[BMWe34Steve]

You can read and clear the check engine light on e34 at home without tools. Check out this link and post the codes you come back with.

http://www.bmwe34.net/E34main/Trouble/Engine_codes.htm

In my 530 I get 13 mpg city and 21 mpg highway.

 

[ricoman1]

Thanks Steve...I'll check the link out.....yeah,all my driving is Highway,and would think at least 18...thats what made me think well maybe the gauge or sending unit is broken...I know I topped the tank off and reset the trip meter,so for sure had full 20 gallons and drove 285 when the sputtering started....I'm going to get that light off,fill up this High Test fuel and see what happens.....oh,and will keep a gallon of gas in back,cause I do want to see it I can get the gauge to go past the 1/2 full mark...if it happens again,then I know I have a bad sending unit and an old Bimmer that gets 13mpg

 

[Mr._Graybeard]

With that long layoff, one or more of your brake calipers could be stuck. After driving a bit, check to see if any of the wheels are hot. Also, the car calls for 89 octane, 91 if it's chipped -- and the knock sensors will delay your timing for fuel below spec, preventing detonation but resulting in reduced fuel economy.

The O2 sensor probably detected a lean fuel mixture when you were running out of gas. That will trigger the check-engine light.

 

[ricoman1]

Hey...not to sound stupid....but how do you know if its "Chipped"..?? Its a 1994 (built in 1993) 540I Touring 4 door.

 

[Mr._Graybeard]

Some tuners provided advisory labels to stick on the ECU (Dinan had one you were supposed to put on the cap of the data plug) but for many, you'd simply have to open up the ECU and check. Then again, since you bought the car almost new, you would probably know if the car was chipped, since you would have done it yourself.

You say your car is a 540i touring ... are you outside the United States?

 

[EyeDoc1]

One thing about gas mileage...

is to do a little research and get a sense of what the mileage was when the car was new and adjust according to the wear and tear. I hope you looked at a fuel filter after having the car sit for so many years. Coughing and sputtering were symptoms I experience until I put a new filter in, and when you removed the old filter and poured the gas from the inlet side of the filter, into a clean glass container, the gasoline was highly contaminated and dirty. It was an eye opener. Mt. Graybeard and I had some long conversations about my Idle Control Valve (ICV) replacement and other issues, and he's quite knowledgable on the E34 series. I've also had issues with vacuum leaks, but I have a 525i and yours is a 540i, so I can't speak to your hose setup concerning leaks. Once I fixed an issue with a failing coil that shorted out only under a load, my MPG went from 14.7 to 19.0. I also started running the car on 89 octane instead of the usual 87 octane from Arco or Union 76. You should have a label on the gas tank door (inside, obviously) and/or in the owner's manual. It's further confusing because the way octane ratings were done in the 1991-1994 time frames may be different from what you see on the pump. A little research will probably give you the correct answer. I miss the days of regular or Ethyl or at least Sunoco 260.

 

[ricoman1]

Hi Guys...
Sorry,been off list for a while....but in reply to some of you...YES...first thing I did was change the fuel filters,fuel pump and of course drain the fuel....even got down in there with a rag and got every last drip out once the fuel pup was out....It drove fine...well it drove good,but not like I remembered...just didnt have that get up and go at high end....I figure thats because I was using 87 oct. in it....and agree,that might be why I had that one time problem...maybe fuel sensors were telling me to up the Otc....The day after this happened,got in car,started it and check engine light was gone......I've since been filling with 89 and runs great....have gone thru 2 tanks of gas and problem has not happened again....maybe it was just a fluke...maybe sitting so long something in fuel lines finally pushed thru and caused the sputtering....guess its a mystery with several reasons to think about.....
G

 

[ricoman1]

Hi Guys...
Sorry,been off list for a while....but in reply to some of you...YES...first thing I did was change the fuel filters,fuel pump and of course drain the fuel....even got down in there with a rag and got every last drip out once the fuel pup was out....It drove fine...well it drove good,but not like I remembered...just didnt have that get up and go at high end....I figure thats because I was using 87 oct. in it....and agree,that might be why I had that one time problem...maybe fuel sensors were telling me to up the Otc....The day after this happened,got in car,started it and check engine light was gone......I've since been filling with 89 and runs great....have gone thru 2 tanks of gas and problem has not happened again....maybe it was just a fluke...maybe sitting so long something in fuel lines finally pushed thru and caused the sputtering....guess its a mystery with several reasons to think about.....
G