Does keeping the fuel above half tank reduce the risks of High pressure fuel pump failure?

Any ideas on this? Are there anyways to reduce the risks?

By the way, does our CTM's have the new upgraded fuel pump that was prone to failing in the R56's?

 

This issue has been hammered out ad nausium on this forum. Some believe that if they run the tank down to nothing they can prove that the owner's manual is fibbing to them about the tank capacity giving them something to brag about or challenge the veracity of the OBC when it tells them they have only 8 miles of fuel left. Others just don't pay attention and burn it all off then wonder what happened much like others who don't check the oil on a regular basis then wonder why their engine seized up.
You've got two indicators working for you, the fuel gauge and the OBC.
Wisdom dictates that depending on the current type of driving and the average location of the nearest refueling station, when it gets down to about a quarter tank, start looking. From a pilot's point of view it is always better to burn off the top half than the bottom. He will also add an extra 1/2 hour flying time to any flight as a matter of safety. As a friend recently stated: "Never be in a situation where you run out of airspeed, altitude and ideas at the same time."


So, when it gets down to about half a tank, consider what kind of driving lies ahead for the next few days and make your decision based on that. I usually fill up at around a quarter tank whether around town or on road trips. That's also a good time to check that oil. Happy motoring!

 

yep, there are numerous threads on this subject that would have been found using the search function. I very seldom let mine go below a 1/4 tank.

 

I almost always let mine get down to one carrot. It's only on one carrot for a mile or two. The OBC usually says I have 50 miles left. My HPFP just started to fail at 80K though, so I'm not sure. I'm going to continue to run the tank down, but NEVER ever run dry!

 

I should have mentioned that the fuel pump is cooled by fuel. No fuel=no pump cooling=toasted pump=$$$. Even letting it run real low causes cavitation which exacerbates the situation. So, why risk potential harm when there is a gasoline store right down the street?

 

I run mine low, still in the first 3k miles but truth be told, the less that 300 miles per tank in a car this size just feels barbaric.

Love the car and the drive, but on the right day of the week, if there was someone saying they could install a double sized tank for me on the side of the road I might just hand them my credit card before asking how much.

 

It did seem odd that the manual tells you to refuel before you get to 30miles range.... With the light coming on at 60miles I had a suspicion it might be BMW trying to reduce HPFP failures without directly referencing it.

 

Yea, there must be something about mechanical thingies with more than two moving parts and low fluid levels that just drives folks nuts.

 

The HPFP is not located in the fuel tank, so the gas level will have no impact on preventing a possible failure.

 

No, it's not in the tank itself but running the pump with little or no fuel flowing thru it will damage or destroy the pump. It is by definition a high pressure pump which without cooling (provided by the fuel) can burn itself out. New ones are around $250 plus the install so why be silly about seeing how close to empty you can get? This fascination towards that purpose just baffles me, the subject has been hashed over so many times already all to the same conclusion.

 

The HPFP is bolted onto the side of the motor. I doubt there is much cooling provided by the fuel by the time it reaches that point.

The OP didn't ask about whether the HPFP can be damaged by running the vehicle out of fuel. The question was about whether letting the level in the fuel tank get below half full would have any impact, apparently based on this mistaken notion that the fuel in the tank is somehow cooling the HPFP.

Also, the claim that "running the pump with little or no fuel flowing thru it will damage or destroy the pump" is clearly incorrect. Otherwise, every time someone ran out of gas, they would have to install a new HPFP.

 

Obviously we need to sit down with at least a case of cold beer to hash this out so we can forget the subject at hand and get on to really important stuff like who's making the show at the final four or what's your best bass bait.

 

The fuel prevents metal to metal contact within the pump assembly which is also why you don't want to starve it of fuel. cooling the internals of a pump is a very differnt concep to the housing cringe attached to a hot engine block.

 

Is there a low pressure fuel pump and if so is that in the tank?

 

I have had my "miles to go" to "---" before. Filled with 11.40 gallons. Should I worry that you will void my warranty?