Fuel pump recommendations
 

I wanted to order a spare fuel pump to have on hand and was wondering what experience anyone has had with the aftermarket ones and if there is any good reason to order complete w/sending unit ? Thanks! :)

I need to do the same. $130 and change for the whole thing from Rock Auto (Delphi, which is alleged to be an OEM by FCP Euro...)

2004 BMW X5 3.0L L6 Fuel Pump & Housing Assembly | RockAuto

Thanks for link! Good pricing! :) I would be tempted to believe that Bosch is actual original equipment though. OEM often means that the manufacturer just was the supplier for something on the vehicle not necessarly the part you are looking at and not necessarly to the same standard. Not saying that some aftermarket can't be as good or better in some cases.

I hear you; just passing along what the claim is on FCP's site for the part. Rock Auto has the Bosch pump itself (no housing) for two bucks more, if you don't mind messing with the mounts and outlet hose.

I'd have no qualms about using Delphi parts... URO, not so much. :D

The OE supplier for the fuel pump that came in my 2001 3.0i was Pierburg. Made in USA. I replaced it with the same when mine went out a year or so ago.

Pierburg was bought about 10 years ago by TI Automotive. So my new pump actually came in a hologrammed box saying Pierburg, etc., but stamped into the Aluminum shell on the pump was "TI Automotive." Taking a quick look on that RockAuto link, and looking at the photo they have with the Bosch unit (not the Delphi one), I see that it looks the same as mine (from memory) and that it also says TI Automotive on it. If you know what to look for, you might be able to read that too.

So I will guess that if you buy the Bosch one there, you might get one made by Pierburg / TI Automotive.

Weird stuff going on now with buying parts online. I recently bought a Gates-branded alternator pulley from RockAuto, and it came in a Gates box, Gates instructions, Gates warranty, but had a Litens part inside it, with Litens name and part number stamped on the part. Checking up with both RockAuto and Gates, and yes, that is how they do it. Gates puts a Litens part in a Gates box and sells it.

I had no problems swapping the new pump into the original plastic assembly. Would do it again.

Also, regarding buying the part before it fails, I agree - good idea. It will wear out just like tires do. I took mine apart when it failed at 173k miles, and the brushes had simply worn out. Everything else looked great in there, but brushes are a wear item and they were done.

Thanks for the info guys! :) Yes, the parts thing is getting pretty crazy, you would think that at least Bosch would be Bosch but not even that is true any more. I found that out with wifes X3, the new Bosch alternator is made in China in a Bosch box while the rebuilt alternator is factory rebuilt by Bosch in germany! (and a few dollars more). Even BMW have thier econo line and BMW white box replacement parts that aren't the same as original! As far as the fuel pump, I don't mind switching only the pump if the rest of the assembly isn't prone to failure, especially if there is a chance of getting a more dependable and quiet pump. And yes, the Uro stuff I avoid as well!

1+ on Pierburg Fuel Pump.

- Search ebay for "E53 Pierburg Fuel Pump" and you should see some listed for $130.

- As long as you don't ever run fuel below 1/8 or have a bad siphon pump (in that case, keep fuel above 1/4), the typical Pierburg fuel pump goes to 180K-200K miles.

my fuel pump crapped out at 149k miles. luckily I was able to crawl home. I replaced with a pierburg pump. don't forget to order the rubber gasket for the tank, maybe a couple of hose clamps. the original clamps were one time use. I had to destroy them to get them off.

Fuel pump recommendations
 

Fuel delivery problem below 1/4 tank has to do with the MAIN pump failing not the siphon jet. *

Not sure where the "below 1/8" comes into play but sounds like a conceptual error. The E53 fuel tank only has 5L of fuel in the surge tank that is closer to 1/20th of a tank than 1/8th.

The x5 fuel tank works by flooding the surge tank to overflow any amount over 5L back to the left side of the tank and uses the siphon jet to constantly pull fuel from the left to the right.

Any time there is more than 5L of gas the pump will be fully submerged there is no difference once you get below 30L or so remaining since the right side of the tank holds no fuel other than the surge tank once below about 30L total.

A fuel pump will last about 5000 hours with pure gas and about 6000 hours with shitty gas (polluted with ethanol). Divide your odometer by your avg speed to get an hour of use estimate. If it's above 5000 time to consider getting a replacement. In fact, I just replaced my wife's and doing the math on mine it's getting close 4500 hours.

I would buy a replacement to have on have but the warranty would start when I bought it but when I install it so I'll just wait until it falls it's one of the easiest repairs to do.

* The seal on the siphon jet can fail but it will still work with a fully operational electric pump. If your right side tank does not report over 1L when left fuel is below 25L then you likely have a weak fuel pump or a leaky siphon jet.

You should at least annually drive down to single digits DTE to confirm your siphon pump is working. When electric pump starts to fail the first symptom will be running out of gas with gas still in the tank.

- Fuel Pump needs fuel to cool to avoid damage. Below 1/8, it is risky. Not to mention being stranded.

- When siphon pump fails (quite a few in E35 5-series forums), fuel is not pumped from L to R side, where the fuel pump is located. When that happens, the fuel pump fails due to overheat.

Look into E39 5-series forum, you will see quite a few like this.

Fuel pump recommendations
 

E39 not like e53. Completly different system.

There is absolutely no difference in how deep the fuel pump is submerged once the tank has > 5L. The design is completely different from road cars. It's designed to keep the pump submerged when going up and down hills and keep the pump submerged when low on fuel.

"Below 1/8 risky" is absolutely incorrect when referring to the E53. In road cars that may still apply. Last time I checked this is the E53 forum where that rule does not apply even a little.

In addition, should you follow that rule (1/4 or 1/8 rule) you INCREASE your chances of being stranded. I know this from first hand experience!

My wife used to use the 1/4 tank rule. It masked the fact her fuel pump was worn out and left me stranded. The ONLY ways to test the function of the siphon jet is to either drive down to single digits DTE occasionally or add a fuel pressure gauge to the return line from the fuel filter and confirm you have enough pressure.

A siphon jet not working will cause a fuel starvation problem with fuel in the tank but it will not damage the pump UNLESS you ignore the problem and try to nurse the situation by keeping the tank full enough (again a case where keep 1/4 tank will cause a problem)

I've seen hundreds of posts about siphon jet and fuel pump failure. I've spent about 20 hours researching how the E53 fuel system works.

I found not one single page that describes the fuel system accurately for the E53 so I literally "wrote the book" with the singularly unique but accurate depiction of how rhe fuel system works on the E53. Literally the only accurate description online that I've seen.

The sedan fuel tanks are different: the lobes are similar left and right. There's a baffle to keep fuel near the pump on hard g-forces but completely different from the x5 which has an actual sub-tank that holds about 5L of gas and will hold exactly that from 30L of gas until 5L unless the main pump or siphon pump have failed. What that literally means is that the x5 does not know the difference between 5 and 30L of fuel.

There are no moving parts in the siphon pump, the only failure points are either a seal or the over pressure relief valve.

After reading hundreds of posts about such failures I determined that the electric pump failing is nearly universally the cause.

90% electric
5% siphon
5% something else (Filter/FPR)

Even when there is a problem with the siphon (leaky seal) once the weak electric pump is replaced, the siphon will work again.

That said, when I ever replace an electric pump I will check for leaks on the siphon side because it's a crappy design with one joint having no actual o-ring seal.

To repeat: zero advantage of keeping more than 1/8 tank of fuel in the E53 only adds inconvenience and more likely to mask a failing fuel pump and increase the chance of being stranded.

If you "always" fill at 1/4 (1/8) tank you will absolutely get stranded because of the practice eventually because you will mask the failing pump and the DTE at engine stall will slowly get higher until it rises above the percentage you arbitrarily decide to fill.

If you on the other hand as I do, drive to the low fuel light you test the siphon jet every tank and will know right away when your pump dies.

My wife's pump was broken for about 9 months before I found out at 6°F on the freeway because she used the 1/4 tank rule. Had she not followed that bad advice I would have known in April not December and could have changed the pump when it was 60°F vs 0°F

e53 Fuel Supply Detailed (fuel pump / siphon pump diagnostic help)

https://r.tapatalk.com/shareLink?sha...6&share_type=t

Low fuel levels on ANY vehicle with a submerged electric fuel pump is baaaad.

The E53 may not suffer the transfer issues the others have but the keeping the pump cool rule still applies.

On my vehicles that never run low on fuel (translation : I don't let my wife drive them) the pumps have never failed. My 323i for instance has the original fuel pump in it with over 400,000 miles.

I treat 1/4 tank as empty. Of course your always going to have those once in a blue moon lower deals trying to find a station. But as a general rule I never let the vehicle get below 1/4 tank.

My wife on the other hand thinks the gas gauge is a devining rod that lets you know there is gas around there somewhere and under 1/8th means you should get around to getting gas sometime, maybe, kinda, soon.

She goes thru fuel pumps.

Crowz: you have a conceptual error in how the fuel tank works in the E53: the fuel pump will be entirely submerged until you have zero L left on the gauge. There is about 3-4L fuel that is not reported by the gauge that will keep the pump submerged down to 0.0L on the fuel gauge.

I would have to do similar research on how the other car models work but the E53 fuel tank is different from all others and there is zero benefit from the inconvenience of chopping 100 miles from your range and greatly increasing the odds of stranding yourself the first time you go a little deep into the gauge.

If you always fill up at 1/4, there is nearly a year100% chance the fuel pump will fail without you knowing it as the vast majority of pumps will just get weak vs fail completely fail. That means you can be like my wife, drive for a year with a broken pump that leaves you stranded the first time you try to get to 1/8 of a tank.

400,000 miles would be the AVERAGE life driving 62mph so if always highway miles that is not that abnormal.

Heat is not the primary concern. Especially with the x5 since if you do run it dry the farthest you can drive once the pump starts to be uncovered is about 10 miles. The brushes simply wear out. When they are worn enough the spring pressure drops the resistance rises and the power to the motor drops and it gets weaker.

The wife used to use the 1/4 tank rule her pump made it to about 128,000 I drive until the low fuel light comes on my pump is going strong at 157,000 (miles).


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Guilty as charged back in the rough days of 2009... :iagree:

Fuel pump recommendations
 

I did the math once. It has saved me well into the 100s of hours not seeking gas stations and filling up in the nearly million miles of my driving history.

I've had one fuel pump die on me while driving (stranded) and it only happened BECAUSE of the erroneous concept that 1/4 tank rule helps (absolutely does not: prove me wrong you can't)*

* I only drive x5 wife has one I have one so only applying to x5. Supposition and myth does not apply proof requires absolute fact.


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http://www.bimmerboard.com/members/q...hon%20Pump.jpg

So where is the part of the e53 tank that makes it unique?

I haven't found anything diagram wise besides the one above.

As in what does it have that makes it special for offroading angles and such?

Crap I just went through my files and I cant find the test we did for this. Its been years but I should have it somewhere.

But I have everything to do the test again except a tank and I can even film it this time around. Youtube didn't exist back when we did the test before.

I have my sons old pump from his Chrysler sebring so I can use it to run the test with. I will post the info when it warms up a bit and I can do it. We proved back in the day the effects of pump cooling by testing the following.

1. Submerged or not.

2. Submerged in small trough or canister vs outside fuel present or not.

3. Gallons of gas volume increased in test tank 1 gallon at time (that one took daays of tinkering to get the fuel back to the ambient temp each time)

Temps were measure for gas itself, the pump itself, gas in canister surrounding the pump, and also direct measurements of the canister housing and sending unit (pump holder).

Was fun testing last time so should be fun to do again.

I'll post up the results when I get them done. Was surprising last time so Im hoping it works out that way this time too.

The only difference this time around is I will have to come up with a tank to do the test with. We cut the top out of a trucks plastic gas tank for the test last time.

Oh and note to self - THIS time around I will NOT use the wifes kitchen probe thermometer.

That part was ugly.

The diagram above is NOT from e53. Read my thread it details all aspects of e53 tank and why it is different from all other fuel tanks.

ALL of the fuel goes into effectively a 5L gas tank. The car is unaware that the tank holds more than 5L of fuel because once there is more it spills out over to the left side. This starts at approximately 27left 1.5L right. Once below about 28L total the right size will report 1.4L or so (the last 3.6L is unreported).

The fuel does go in circles which will cool the liquid more than if it was just the 5L but there is never more than 5L surrounding the pump once the total fuel is about 28L of gas. (30%).

Yes, really. The bottom of the right side of the tank is approximately MIDDLE of the depth of the left side. The surge tank is in the back of the right side and it's a "dent" who's top lines up with the bottom of the right lobe of the tank.

See my diagrams and photos. Like I said, after 25-30 hours of research I found ZERO accurate pages describing the workings of the E53 Fuel pump. They all used inaccurate references based on the sedan designs and were wrong, every single one.

When I eventually figured out exactly how it works (even siphoning out the surge tank to determine it's exact volume) I literally know more about the E53 pump than any accessible resource online so I shared that info with xoutpost because they are deemed by me to be the most worthy of my contribution.

To be clear: the pump needs to be submersed fully at all times. That is clearly part of the design and spelled out in some of the BMW technical reports. I'm sure that's why the gauges are designed to report approximately 4L less than the tank actually contains:

When the fuel gauge reads zero you will have approximately 1G or 3.5L of gas: double what is necessary to submerge the entire fuel pump which is at the bottom of the 5L surge tank.




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https://uploads.tapatalk-cdn.com/201...582d692e73.jpg

The little "bump" on the bottom of the tank is where the fuel pump resides. The pump is so low in the little bump that with 5L of gas the pump will be completely submerged at a 30° nose up or nose down attitude. (or left or right but I wouldn't attempt that one I don't know at what angle the x5 will tip but I've had mine at 37° down 12° list before and it was awesome.

The design is great! I couldn't start my Ford explorer with 1/4 tank of gas when parked in an angle driveway and that was only maybe 8° angle. I had to put in neutral, coast to the road then when close to horizontal the car will start what a moronic design for supposedly an off road vehicle.

The diagram you showed is one of the hundreds of incorrect resources I mentioned when researching the fuel system of the x5.

100% of the existing resources referenced similar designs implying or explicitly declaring that the x5 fuel pump had two equal lobes which can not be more innacurate!

If you break the x5 tank into three virtual tanks it makes more sense:

Tank A is used first, holds about 60L
Tank B holds about 28L and holds the spill over from tank C
Tank C holds 5L and is where ALL the fuel is actually pumped.

When tank A is empty, tank B continually pours fuel into C to the point of overflow to keep it completely filled to 5L up until tank B is empty. This keeps the pump submerged even at extreme angles and down to 0.0 gallons remaining since there is almost 4L more in the tank than reported by the instruments.

It's an absolutely brilliant system but leads to some confusion during trouble shooting that will have people draw the wrong conclusions such as "keeping more than 1/4 tank will help something" or "a defect in the siphon jet will wear out the electric pump" neither of which applies to an x5 .

(The fuel pump is fully submerged by recirculating fuel down to 1/18th of a tank well below the low fuel light)

(In the EXTREME rare case of a siphon jet failure you will fuel starve having run for no more than ten or 15 miles with the pump not submerged it will not likely cause any significant harm unless you follow the "fill at 1/4 tank rule in which case you can cause damage by running the pump uncovered without realizing it because once below 1/3 tank the ONLY thing keeping the pump covered is the siphon jet).

These are just facts based on research and first hand measurements and tests (and a few mouthfuls of 93 octane).

There is no more accurate resource for the e53 fuel pump online. (Than mine). My digrams are based on my measurements and photos of an actual e53 tank I took apart not supposition upon speculation upon myth based on 1950s gas without ethanol. It's cold hard facts.

So just for the record it makes no difference how much fuel is in the tank as long as the amount need to cover the pump in the depression is there right?

So if there is 5L of fuel then the pump will not run cooler by adding more fuel right?

That is basically correct. When there is a little more maybe up to 10 L the recirculation of fuel will help a little bit but basically until the low light comes on the pump will get no increase in cooling. Again a brilliant design needing the bare minimum of fuel to run the engine and to cool the pump.

When the fuel is more than 5L, the excess goes in circles.

The fuel pump sends fuel to the filler/regulator, what is not used goes back to left side, that collects fuel from the left side and dumps into the right side which spills like a waterfall back to the left side. Any time the left side of the tank is cooler than the right side, some chilling will occur but since the turnover is limited and slow, it's not a significant factor so the reality is the fuel pump will be completely submerged by fuel that is cooled by conduction to the very large plastic fuel tank, you will have effective fuel pump cooling down to 0.0 on the gauge.

Also, it's important for the reasons above to test the siphon system periodically so you know the pump isn't worn and the seals are working.

Test Six should report about 1.3-1.4L right side on level ground driving steady state. If you learn what your particular car shows you can verify the system is working. If the right side ever drops below your baseline most likely the pump is worn out but also a good chance the stupid no o-ring seam on the siphon jet has failed. That can be fixed for free don't replace with the identical flawed design.

Excellent info Andrewwynn! :) I have read your thread on how the E53 fuel system works and appreciate all the effort you put into posting your findings! :thumbup: Do you have a part number for the O-ring you added to the syphon jet fitting? Maybe that could be repaired differently ?

Actually our test showed the plastic tank didn't provide any measurable cooling effect for the pump in our test. Volume of fuel did but sitting directly on the tank bottom or suspended in the plastic bucket the tank came with didn't help with pump temperatures.

Free floating without the bucket provided the most cooling of the pump.

One thing we found strange was that without a pressure regulator the pump ran much hotter than with the regulator but a dead head system aka no return got the hottest.

I just replaced the fuel pump in my '05 3.0L. I see absolutely no reason to replace the entire assembly, you can replace the pump separately. I was sitting at a traffic light at the exit from Sam's Club, the light turned green and I stepped on the gas, the engine stalled as if it was sucking air. I had come from the gas station in the last 25 miles so the tank was filled. I pulled the old pump and did a continuity test, it was open. The new pump had resistance. It could have taken as little as 30 minutes to replace the fuel pump, but I had trouble with the seal -- which is actually easy to not have trouble with -- that slowed me down. I would not recommend changing the fuel pump on a full tank of gas, but sometimes you can't always get what you want.

Personally, in all of my years owning cars, this is the second fuel pump that failed me. I would not bother stocking a pump for the next time.

The seal must be installed onto the pump assembly before installing into the tank. Was that the problem.

It's not a difficult process to swap the pump and you can likely end up with a better pump doing that. I swapped the whole assembly because I found one with a year warranty that was a price too good to pass


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I can confirm that the TI Automotive pump is what came in the box when I bought this on Amazon: https://smile.amazon.com/gp/product/B00PQXAWQI

I got lucky and found one open box on Amazon Warehouse Deals for $109. Guessing somebody bought it and thought they were getting the whole assembly, or couldn't figure out how to get the old pump out of their existing assembly without breaking it. :D

... or maybe they were hoping to get a Bosch, and thought they were getting a lesser brand with TI Automotive. I've also had good luck with great deals from Amazon Warehouse Deals. Usually a brand new item in a damaged box for 40% off.

I couldn't find my tool I made for taking off the fuel pump "nut". So I came up with a very easy solution that people should use. I clamped two separate vice grips on to the little nubbins and used a quarter inch Drive extension as a handle between the jaws and it twisted right off

https://uploads.tapatalk-cdn.com/201...b12750ad1a.jpg

^ I used a flat head screw driver and tapped it loose with a mallet.

That's a good idea! Did find that you needed to replace the seal or could it be used again? How hard is it to check the jet pump o-ring from that side?

You're advised to replace it, but I reused mine because it seemed entirely undamaged and wasn't dry or brittle in any way.

Man, their loss if that's the case! TI Automotive fuel pumps have been around for decades under the name "Walbro". I was thrown off a bit myself at first but a little bit of research on what was actually in the box cleared it up. It seems like a quality part.

Fuel pump recommendations
 

After 17 years both the seals on both our X5s were in perfect condition and I reused them as needed. I think the new pump came with a new seal so I have 1 of 4 replaced.

I wet the seal with gas so it will slide in nicely and I rotate the seal around in the tank hole to ensure its seated perfectly.

It's a very tight fit probably takes 30-40# of force to install the pump/sender unit.

Don't make the mistake of trying to put the seal on the sender unit first. The seal will often come out with the unit tricking you into thinking that you should put the seal onto the sender before installing into the tank: that will lead to A LOT of frustration.

The first couple times I used some clean engine oil to lubricate the seal but gas works fine. The tiny amount on the outside of the seal will evaporate quickly and is outside the enclosed people part of the cars envelope.

I discovered my siphon pump was not working properly last night and rebuilt my siphon jet pump.

Siphon pump DIY repair

https://r.tapatalk.com/shareLink?sha...4&share_type=t

Very detailed DIY "cookbook" on the process to rebuild a leaking siphon pump (this will work on any similar BMW siphon jet).

I'd be willing to bet a majority of x5 that have 150,000 miles with an original siphon pump have this failure to some extent.

It's a flawed design; the joint with the o-ring is held together from 4-6 cm away! It will be at a 5° angle by the time the failure is discovered.

Both our x5s had the exact failure.

https://uploads.tapatalk-cdn.com/201...6b21b9cd11.jpg
Mine

https://uploads.tapatalk-cdn.com/201...5ade913879.jpg
Wife's

As you can see: identical failure.

There is a clear design flaw. The joint with the o-ring is held together not symmetrically around the o-ring as it should be, rather it's held from 4-6cm away offset to the side.

The pressure causes the joint to twist and eventually the o-ring can pop out of the groove and a huge percentage of the gas sprays out into the tank and no longer pulls the gas from the left to right side of the tank.

It's such a bad design and it's a relatively easy fix that I would as preventive maintenance replace the o-ring seal and re-work the "useless seal" on any BMW car / truck that uses this style of siphon jet.

A simple hose clamp around the two fittings would probably prevent the problem before it happens.

I can't imagine how many $100s of 1000s have been tossed away to dealers and indys who have replaced the entire siphon jet and sending unit simply because the o-ring failed.

I'm not sure which side you are asking about.

With an inspection camera or a dental mirror you could check for the siphon jet failure from the right side. Actually even without, as long as the tank has enough gas.

If your right side reads over 2-3L, then the two sides are flooded over the hump in the middle.

If you have the right side open enough to see inside and turn the key to on (not start no need), if the siphon jet is leaking it will cause all kinds of chaos to the surface of the fuel.

If the siphon seals are solid, you should only see disturbance coming from under the surface on the right side.

It's probably safer to check from the right side, as you can tell from my crazy video where my iPhone got sprayed by gas, you'd avoid that completely by investigating from the right tank opening.

Thanks! Awesome post! Do you have a size/part number for the o-ring?

Fuel pump recommendations
 

Unfortunately I don't. The one I used was way undersized diameter with a larger than spec cross section (I wanted it to be very tight so it would be impossible to jump the track again). If the ID of the groove is 25mm the o-ring I used was at most 20 but instead of 1.5mm cs I had one that was 2.0. When stretched out the cs shrinks so it worked out great. Sorry I didn't have my caliper in the house where I did the o-ring so I didn't think to get an exact size.

When using an undersized o-ring like that, it's important to run a smooth tool around the entire o-ring once or twice to evenly distribute the o-ring so it's not bunched up somewhere.

It almost looks like the groove would be wide enough for a backup ring ??

No that wouldn't be helpful. One chubby ring a couple sizes downsized from spec and a thicker cs is perfect.


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Me too. I also re-used any seals unless they came with the new fuel pump. Just between you and me though. The right way is of course to buy the BMW special tool and replace every seal and screw you can see.

https://uploads.tapatalk-cdn.com/201...9039ab6fdc.jpg

Impossible reading. This needs addressing as it says my car has about a gallon more than it does! I probably put the pump in crooked (foot not in it's base)

@andrewynn, did you get this figured out? Was the foot not in because of trying to keep things straight with the zip tie?

No it's the other side. The side i fixed reads correctly.

I think I missed the foot position when installing the starboard side pump / sender. I will examine with a fiber optic camera from the other side (or filler neck) before I remove it to figure out exactly what is wrong. It seems the float is hitting the side of the tank and stopping at 5.4 vs 1.4L (about a gallon incorrect).


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Haha, that sounds like a good application for one of those fiber optic cameras that I have been looking for an excuse to buy! :) right after I finally splurge on a set of electronic ears! :)