Dreaded "30 Mile" Gas Range...

[Crowley]

Originally Posted by mega

the fuel cools the pump, it's suspended with a pickup below it

when the fuel tank is low, the pump is above the fuel and not cooled nearly as good

I try to never go below 100 mile range, that's just over 1/4 tank

[crzy4135i]

Originally Posted by Crowley

I've always done that with my '87 saab 900t and it still has the original primary and small feeder fuel pumps at approx. 250k miles. I keep waiting for one of them to go bad but it hasn't happened yet. I might go ahead and replace them just for piece of mind.:biggrin:

[1Ronnie]

I've always run till close to E just to save time, running it to 1/4 means filling 5 times instead of 4 ... damn another sacrifice I'll have to make ... lucky she's woth it !!

[jeremyc74]

I have to say that I'm a little shocked that so many people buy into this nonsense. Do you guys really think that BMW's engineers can create cars this good, and don't take fuel level into consideration when designing the fuel pump motor? Come on now! Heat DOES NOT degrade the life of an electric motor, provided it doesn't exceed the normal operating range. There's no way in hell BMW's engineers are counting on the owners to maintain more than 1/4 of tank to keep the fuel pump within that range.

This whole thing was brought on by a few failures in early in-tank pumps, which was corrected decades ago, but people still swear by it. It amazes me.

You could run this car CONSTANTLY with a 1/4 of a tank of fuel in it and not shave one day off the life of the pump. The danger is to the engine in running out of fuel under boost, and has nothing to do with cooling the fuel pump.

[BeamerDreamer]

I'm no expert on the subject but I think the warning is more to prevent you to keep from running out of gas. I don't think that running the car near empty will effect the car's mechanics. A problem exists if you run the car completely empty and air gets into the fuel injection system. Only the could I see a mechanical malfunction. I'm sure the fuel pump is designed well enough to operate when there is less than an optimal amount of fuel in the vehicle. If BMW engineers were stupid enough to not incorporate that into the design, I am sure that there would eventually be a recall.

[sybarite]

Originally Posted by CBLW

I know that owning a BMW is an investment...

First off:
NO mass-production modern car is an investment. None.

And secondly

It feels like such a waste of money to have to keep on filling up the tank at that mark, if it's for no real reason at all...

Whaaaaa?

[imported_mega]

Originally Posted by jeremyc74

I have to say that I'm a little shocked that so many people buy into this nonsense. Do you guys really think that BMW's engineers can create cars this good, and don't take fuel level into consideration when designing the fuel pump motor? Come on now! Heat DOES NOT degrade the life of an electric motor, provided it doesn't exceed the normal operating range.

it's not nonsense it's just how it is, common sense 101, and a little research goes a long way, these fuel pumps are suspended, fuel cools the pump, bmw engineers have not created some new space/time continuum where heat does not affect parts

besides, running them completely out of fuel DOES hurt them, quickly, why even risk that

[jeremyc74]

Originally Posted by mega

it's not nonsense it's just how it is, common sense 101, and a little research goes a long way, these fuel pumps are suspended, fuel cools the pump, bmw engineers have not created some new space/time continuum where heat does not affect parts

besides, running them completely out of fuel DOES hurt them, quickly, why even risk that

Electric motors don't need liquid cooling. I've done plenty of research on it, and I happend to be an electical engineer in the automtive industry. Electric motors run hot by design. Anyone who designs one that requires fluid cooling and doesn't take the variable level into consideration would be an idiot. It's just not the way it's done. Also, running a pump dry for a few seconds won't do anything to it at all. I'd love to see you produce some proof of that.

You run out of fuel, the car dies, the pump stops. You put gas back in it, start it up, and go on with your life.

[imported_mega]

Originally Posted by jeremyc74

Electric motors don't need liquid cooling. I've done plenty of research on it, and I happend to be an electical engineer in the automtive industry. Electric motors run hot by design. Anyone who designs one that requires fluid cooling and doesn't take the variable level into consideration would be an idiot. It's just not the way it's done. Also, running a pump dry for a few seconds won't do anything to it at all. I'd love to see you produce some proof of that.

You run out of fuel, the car dies, the pump stops. You put gas back in it, start it up, and go on with your life.

google is your friend or search any bmw forum


http://www.google.com/search?q=bmw+f...ient=firefox-a

http://forums.pelicanparts.com/showthread.php?t=411077

I could post hundreds of these, people are dumb and run out of gas and burn pumps up all the time

I personally know of 2 people that did it, ran out of gas and the tank pump was toast


by now, everyone should already know the 135i fuel pumps are weak to start with

[jeremyc74]

Originally Posted by mega

google is your friend or search any bmw forum


http://www.google.com/search?q=bmw+f...ient=firefox-a

http://forums.pelicanparts.com/showthread.php?t=411077

I could post hundreds of these, people are dumb and run out of gas and burn pumps up all the time

I personally know of 2 people that did it, ran out of gas and the tank pump was toast


by now, everyone should already know the 135i fuel pumps are weak to start with

Your links are garbage. There's no proof there at all. The people you know probably weren't even out of gas, the pump just failed. The issue with the 135i pumps is a manufacturing defect, and has ZERO to do with tank level.

Do you guys seriously think BMW's engineers are dumb enough to allow the pump to burn up just because you're running around with under a 1/4 of a tank of fuel? These cars have more safety checks built into the software to prevent damage than anything I've ever owned.

What I see here are a bunch of people with very little understanding of electrical parts second guessing the engineers who have spent thousands and thousands of hours testing this stuff, and to be honest with you it's downright comical.

[imported_mega]

Originally Posted by jeremyc74

What I see here are a bunch of people with very little understanding of electrical parts second guessing the engineers who have spent thousands and thousands of hours testing this stuff, and to be honest with you it's downright comical.

I hope nobody believes this guy, bmw has no magic solution for running a pump dry

[jeremyc74]

Originally Posted by mega

I hope nobody believes this guy, bmw has no magic solution for running a pump dry

You don't need one. Running a fuel pump dry for a couple of seconds won't hurt them.

[imported_mega]

Originally Posted by jeremyc74

You don't need one. Running a fuel pump dry for a couple of seconds won't hurt them.

I agree with this, the trouble is people are stupid, and they will sit there with the power on wondering why it wont run

the whole time the fuel pump is running dry, on bmw's they will blow a fuse if they start to pull too many amps

[jeremyc74]

Originally Posted by mega

I agree with this, the trouble is people are stupid, and they will sit there with the power on wondering why it wont run

the whole time the fuel pump is running dry, on bmw's they will blow a fuse if they start to pull too many amps

And once again, you're demonstrating that you don't understand much about how this system works. On modern cars the fuel pump ONLY runs for a couple of seconds unless the crank is turning. I know from personal experience it's been that way on BMWs since AT LEAST the early '90s. Anyone who's ever tried to bleed air out of a fuel system on a modern fuel injected car knows this.

[imported_mega]

It's like talking to a wall, I give up, unsubscribing from this thread

run your car out of gas, I don't really care if you do anyway, don't cry when it's broken

[CBLW]

lol This thread turned rather hilarious quickly. Thanks for all of the input guys. I honestly have no idea what to make of all of it, but maybe I'll share the commentary with my dealer's service department and get a final answer from them.

[crzy4135i]

Originally Posted by mega

It's like talking to a wall, I give up, unsubscribing from this thread

run your car out of gas, I don't really care if you do anyway, don't cry when it's broken

Don't get frustrated. The great thing about forums is you can post your opinions along with everyone else. People have different opinions. In the end.. each person will do whatever they want with their own car.

Just like the lady putting gas in her new looking SRT-8 charger a couple weeks ago at costco. I was in line behind her and saw everything. She was trying to fill the tank from the wrong side and the hose wouldn't reach. She went ahead and yanked on the hose and finally forced the nozzle into the tank. The problem was she had the gas hose rubbing all across the trunk lid paint. I wanted to say something but.. F-it. It's her car. Oh, I hope it wasn't her husband's car.

[spongeWorthy]

Originally Posted by arrons1969

I've always run till close to E just to save time, running it to 1/4 means filling 5 times instead of 4 ... damn another sacrifice I'll have to make ... lucky she's woth it !!

and just to play devils advocate.
would stopping 25% more frequently not make a more than negligible difference in cost / convenience?

for instance lets say on average you filled up twice a week when stopping near empty.
thats 3.5 days between fillups.
thats 8 fillups a month,
or about 104 fillups a year.

at 3/4 of that (or at 1/4 of a tank) you'd stop every 2.625 days,
or about 11 times a month,
or 139 times a year.

the cost per fill ups X frequency would end up being a wash,
but making that many more stops seems significant to me,
in terms of convenience, and possibly in terms of overall mileage.

[pumaknight]

Mine is a bit odd - when the light comes on and it beeps to tell me 30miles remaining in tank, I fill her up....Now it shoudl take 53ltrs, but only takes 47ltrs......some reserve tank eh?

[ajshanny]

Anyone have any thoughts as to why the 135i owner's manual includes the following statement: "refuel as soon as possible once your cruising range falls below 30 miles/50 km, otherwise engine functions are not ensured and damage can occur."?

What engine functions would be affected that would cause the damage?

[aarong_m3]

I went to 15 miles left and got gas and nothing happened. And i have JB2.

[BlackjackMulligan]

My guess is that if there are any particles or water from the gas or the tank they would settle to the bottom. If the gas got that low they may be sucked in, although I don't know how it would get past the fuel filter (the particles at least). Maybe they could gum up the fuel pump, etc. Just an educated guess..