finicky gas guage

[mike wong]

my gas guage seems to start off slow, then zips from 7/8th's full to 1/8 tank fairly quickly. Pushing the Range button on the OBC says distance left is 45 miles - which seems correct. However i can drive another 40-50 miles without either the gas guage or OBC range changing.

Can still drive more until the needle drops to empty, then in a little more, the reserve light will finally come on. But filling the tank to the top of the filler neck required only 16 gallons. I thought the capacity was 19-20 gallons (will have to check the owner's manual...)

I'm not really complaining - as this should prevent me from ever running out of gas.

But last week driving from Bay area to LA, I felt like stretching it - but chickened out at the Grapevine when the guage read 1/8 tank remaining -
with no other gas stations for 40 miles...

NE1 else's gas guage behave like this - any adjustments?
the float in the tank seems to move freely.

mike

[Jr ///M5]

I have to keep a sharp eye on the M5's gauge when it reads about 3/8 of a tank and start looking for an Amoco. The bottom will drop out of it and suddenly it will read near empty. Maybe it's a built in safety factor to keep the fuel pump submerged in fuel, but I've almost got caught a couple of times running low like you said with 60 miles left according to the OBC.

Jr

[Phil M]

ive noticed it too. mine sits at 40 miles on the range for a LONG TIME. the light goes off and on for like 3 days when it gets that low. I've never really seen my range dip below 35, but have ran out of gas before. You should try seeing how far you can go. just carry a gas can in the back. hope that you dont die on a hill going up though! (guess you could probably drop it in neutral and 180 her anyways though) I've just learned to fill up when i see her getting past the 1/8 mark.

[AllanS]

Mine starts off fine, then drops to half way quickly, and slowly goes to empty. But even when the reserve light comes on, just like yours, it only takes a max of 17-18g to fill it back up. Now that I know what's happening, I just live with it (and make sure to reset the counter on every refill).

[mike wong]

Jr,

when yours reads near empty, is it really empty?

as Alan's, Phil's & my gas guages read near empty, but really have quite a lot: 3-5 gallons left. My needle has to get right on top of the E line, before the reserve light comes on (OBC range said 35 miles, but still had 5 gallons left in tank).

When my old 733's reserve light comes on - there's 2-2.5 gallons left (no matter what the guage says). "Do NOT collect $200; Go directly to gas station!"

mike



I have to keep a sharp eye on the M5's gauge when it reads about 3/8 of a tank and start looking for an Amoco. The bottom will drop out of it and suddenly it will read near empty. Maybe it's a built in safety factor to keep the fuel pump submerged in fuel, but I've almost got caught a couple of times running low like you said with 60 miles left according to the OBC.

Jr

[Jr ///M5]

According to the pumps at the station it is, I try not to let it get that low. But seeing a quarter tank on it the other day and after going about 5 miles, the reserve light flashes and catches my eye. It's time to find a station NOW!!! Fill it up, and sure enough it's close to empty, with about 3 gallons left.

[TimGinCentralNJ]

...as was also the case with my 1st E34, an Islund Grun 1991 535iA.

At least they're consistent!

Tim G.
'91 535iM
Islund Grun Met.
122k


Mine starts off fine, then drops to half way quickly, and slowly goes to empty. But even when the reserve light comes on, just like yours, it only takes a max of 17-18g to fill it back up. Now that I know what's happening, I just live with it (and make sure to reset the counter on every refill).

[1992 BMW 535i]

I've never had a problem. All I do is go by the trip computer which seems to be 99% accurate. When it says 20KM until empty, you have 5KMs to go.

[AllanS]

Same color too, but i've got you on mileage. I just got used to it, and it IS consistent, which makes it easier.

[DanH]

For those of you who like to regularily drive about on reserve fuel, I'd recommend you buy an extra fuel pump and keep it in your trunk, since you'll soon be stranded somewhere with a burned out pump.

I learned my lesson the hard way, when I used to almost always run my tank dry on my truck...

Good luck!

[Mewsy]

I have exactly the same problem with the guage on my '90 525. I was actually going to write in to see if anyone had a solution to it. I have only had the car for 2 weeks, and was unsure if it was a BMW quirk or if my float or guage needs attention.

[henryw525i]

I swapped mine over with one out of a 95 540i (my car is an '89) and the new one still isnt accurate, it was more accurate than the original one. So yes it is a BMW trait that gets worse as the sending unit get older.

E36's solved the problem by having 2 sending units then my taking the average readout of both...more accurate ;)

[ryan roopnarine]

http://bmwe32.student.utwente.nl/johan/fuel_sender/fuel_sender.html

maybe this will help some of the unsatisfied volk here, courtesy of sean and johan. in florida, whenever i get down to the last 3 galls or so, i always get a notable "hiss" and spritzing when breaking the nozzle door seal with the gas pump nozzle. must be the temperature.

also, that two sender setup henry mentioned is krap, imho. the fuel pump side sensor is generally only used to trigger the low fuel light, the other side does most of the work, which defeats the purpose i would think. trying to help a friend's cousin fix his 850i and its severe gas gauge reading troubles, thought it had the wire set like ours did, it has two hard ass rubber seal deals that you have to break to get the sender/fuel pump out, plus unbolt the back seat to get to (it don't pull up like in our cars). i think he may have given up and taken it to a mechanic by now, i'm not sure.

[Warren N.CA]

it was dead accurate. But my gas guage is really whacko down at the bottom. Nose attituse of the car affects it a lot. BTW, I hears we should not go below 1/4 tank, in order for the fuel pump to get proper cooling.


my gas guage seems to start off slow, then zips from 7/8th's full to 1/8 tank fairly quickly. Pushing the Range button on the OBC says distance left is 45 miles - which seems correct. However i can drive another 40-50 miles without either the gas guage or OBC range changing.

Can still drive more until the needle drops to empty, then in a little more, the reserve light will finally come on. But filling the tank to the top of the filler neck required only 16 gallons. I thought the capacity was 19-20 gallons (will have to check the owner's manual...)

I'm not really complaining - as this should prevent me from ever running out of gas.

But last week driving from Bay area to LA, I felt like stretching it - but chickened out at the Grapevine when the guage read 1/8 tank remaining -
with no other gas stations for 40 miles...

NE1 else's gas guage behave like this - any adjustments?
the float in the tank seems to move freely.

mike