# My E34 is lying to me

This happened to me yesterday driving from my house. The low fuel light has been on for a couple of days, but the OBC tells me I can drive
another 39 km. I figured the car knows what it's talking about so I don't worry about it. However, just a couple of minutes later the car starts running rough. Realizing that I'm out of gas I try to drive to a local gas station. I almost make it, the car stalled just about a block away with the OBC telling me I can go another 37 km?! WTF, that's 25 miles, yet the car *is* really, positively, out of gas. Is the fuel range figure calculated including how far you're able to push the car in an emergency too, or what? Anyway, so I call a friend as I'm parked by the curb. Adding insult to injury a E28 driver gives me a pissed look and gestures as if I'm in his way or something, yet non of the other vehicles passing me where having a problem. Too bad he didn't stop though, I could have told him a couple of things...
Ulf
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Your car is probably bent in half from dragging that damn trailer, and the last gallon of gas is stuck where the sending unit can see it, but the pick-up can't get at it. <hehehe>
The Low Fuel light seems to be working right to me, you ignored it's warning and now it is explaining why you are walking. If it said that you sitll had 100 miles remaining, then I'd wonder what's up, but you got down to within the last gallon of gas remaining.

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Jeff Strickland wrote:

Nah, my car is fine. Ready to pull another trailer... :-)

Well, I think that if the OBC is unable to correctly calculate the distance it should err on the safe side, and not overestimate it.

Ulf
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

the
warning
within
It probably worked fine when the car was new, but it't getting on in years, and there was trouble with the gas a couple of years ago that made fuel level sending units go haywire. I don't remember where you live, but the bad gas was all over the southeast and up the eastern seaboard. It would be nice to have a device that knew precisely how much fuel remained, but there are just too many variables to deal with, and time is among them.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Ulf wrote:

The OBC is not that accurate. When the low fuel light comes on, it's best to put fuel in it.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

I usually fill up when I get down to 1/4 tank. This applies to ANY car as it keeps me from getting sidetracked and having to push.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

I once ran my E39 to 5 miles from empty on the OBC - and a long time after the light had come on. And it took the stated capacity of the tank to fill it.
So I trust mine. The E39 IIRC has twin fuel level sensors. Dunno if the E34 has.
--
*Never underestimate the power of stupid people in large groups

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
I have run my car to "0 miles left" but had not run out (but close!)
DAS
For direct contact replace nospam with schmetterling
--
"Dave Plowman (News)" < snipped-for-privacy@davenoise.co.uk> wrote in message
news: snipped-for-privacy@davenoise.co.uk...
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

Like your speedometer & "Dubya" - maybe we should all start to worry!
Tom
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

I take it you're not a rocket scientist?
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
dizzy wrote:

Is that a requirement owning a BMW?

Ulf
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Ulf wrote:

The OBC gets one very important piece of information externally to determine how much further you can go. It gets the fuel level from the fuel tank sending unit. It takes that level reading and calcul;ates how far you will be able to go based on an average of your recent mpg calculations. If the sending unit lies to it then the OBC will also lie to you.
As an aside, it's generally considered a bad idea to run your tank so low. Aside from having to walk, it stresses out the fule pump. You probably don't want to make a habit of that...
-Fred W
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
If you run your tank real low you also risk sucking up some of the shit that sits in the bottom of most gas tanks and clogging your filter or damaging the pump itself.
Steve

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
It is simple, Ulf. You are a dumbass AND you have bad gas.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Calling people names only reflects on the caller. If the OBC indicates many miles to go it is not unreasonable to be able to go at least another few miles.
Having done experiments on my car (spare 5-l cannister in the boot!) I know I can run my car down to 0 miles left without running out, though I would not try it on a regular basis.
DAS
For direct contact replace nospam with schmetterling
--
"F Fletch" < snipped-for-privacy@webtv.net> wrote in message
news: snipped-for-privacy@storefull-3132.bay.webtv.net...
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

know
I thought it was common knowledge that running your car to almost empty is not advisable. If the OP was not aware of this, then he is now. If he was aware, then he's a mute posterior.
I just don't understand why someone would run their tank to almost empty, just to save them from having to re-fill a hand-full of miles sooner next time.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

## Site Timeline

• ### 1986 325es Power steering leaks

• - last updated thread in BMW Cars and SUVs

• ### 2006 GMC Envoy, (denali) rear air suspension problem

• - the site's last updated thread. Posted in Automotive Technologies
• Share To

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.