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Save yourself up to $200 and some headaches - Electric Fuel Pump PM

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#1 · (Edited)
Fuel Pump Failure Epidemic 2012

So I have been around this forum and many of the other BMW forums and what seems to be a reoccurring theme is after about 7 years is most of the E38, E39, E46 and other similar vintage BMW's not newer than 2006 are have failing fuel pumps at a very high rate. Probably a rate of about 100%, as I say its not if, but when! 5 years later in 2017 fuel pump failures are still happening and probably at a higher rate due to the age on run hours as the E46 is not getting very old and almost to the point of beyond maintenance and actually at the point of restoration.

So a word to the VERY wise, if you have a spare $150 or so and a couple of hours, order yourself a replacement fuel pump, new fuel pump relay and fuel filter and replace them as a PM item.

Here is one good example of someone that mentioned his "Micro sample of 4 E46's" all seemed to have fuel pump failures between 70-140k miles. Note that mileage is really not a complete indicator for fuel pump lifespan, run hours are what matters, but this is hard to capture. Also keep in mind, in general terms the fuel pumps just plain wear out. A fuel pump that has 70-100k miles is likely over half way worn out. When will it fail, this is anyone's guess. Usually when it is very cold or you least expect it to fail! This thread also has some good pictures: http://forums.pelicanparts.com/bmw-3-series-e46-1999-2005/712384-e46-fuel-pump-failure.html

There are really 2 typical fuel pump related failures, but there can also be some more minor pump related problems where the fuel system will drop too much static pressure when the pump is not running. The static pressure drop can usually be caused by one or more of the following: Leaking fuel pump output check valve, Leaking fuel pressure regulator, Leaking fuel injectors (rather rare), or a basic fuel leak due to hard injector O-rings, a loose or damaged flexible hose connection or possibly even a leaking valve a the fuel pressure test point.

One case is where the fuel pump hard fails and does not provide any fuel to the engine at all. This is a pretty cut & dry situation where the problem is rather obvious. A quick and inexpensive way to determine if you are have fuel supply problems is to purchase a $3 can of starting fluid, remove the air filter and give a good, solid, 2 second shot of starting fluid into the intake path/MAF inlet. Then try to start the engine, if the engine starts then almost immediately dies, then you could repeat the starting fluid process, but more than likely the starting fluid test has confirmed you have fuel supply problem. This will most likely be due to a hard failed fuel pump, but it is worth checking the fuses and possibly switch the horn and fuel pump relay just to rule these out as causes of your no start problem. In a bind you can often get the fuel pump restarted with a number of good smacks on the bottom of the fuel tank on the passenger side. If this does not work, you could remove the rear seat bottom and the fuel pump access cover on the right side of the car and use the butt of a hammer to whack on the top of the fuel sending unit. Be careful not to hit the connector, wiring or the output connection where the fuel line is connected. If you are LUCKY, you could get the pump to start again and maybe make it to your destination.

Another failure mode is a soft fail fuel pump that fails to put out enough pressure and/or fuel volume. These are far harder to identify and symptoms may appear to be intermittent or very minor. In some instances the problems may not even seem fuel related. Surging, poor acceleration, possible lean codes, extended cranking when starting, running out of fuel when the gas gauge shows 1/4 of a tank. Soft fail fuel pumps are not really worth diagnosing in my opinion. For the price of the pump and how easy it is to install, I would just plan on replacing your pump if it is more than 7 years old and you have unidentified driveability problems.

In addition to the pump being a problem, fuel filters are very often neglected and over looked and can cause similar issues to a soft failed fuel pump. Please carefully read the following information on fuel filters below.

SPECIAL NOTE ON FUEL FILTERS - since the early 80's fuel filters have much finer filter elements and will catch far smaller particles to protect the fuel injectors. Although many cars have large fuel filters and manufactures claim the filters can be changed every 50-60k miles or are even considered "Lifetime", based upon field observations, I would HIGHLY suggest replacing your fuel filter every 30-50k miles. If you open up any of these filters after 25k miles, they are often caked with a very fine black film. This black film builds up and starts to restrict fuel volume and pressure and can cause unusual engine performance issues. From years of monitoring Forums and my own observations, it seems that many of fuel filters with the black film seem to be cars from the East Coast or North East corridor of the US. This may be due the age of the storage tanks both for the distribution network and the in ground tanks at the local gas station. While this thread is primarily focused on fuel pumps and fuel pump failures, PLEASE understand that replacing the fuel filter is an assumed maintenance item. I do not recall seeing specified service interval from BMW for these fuel filters, they may consider them "Lifetime", but I would HIGHLY suggest you consider changing them every 30-50k miles to be on the safe side.

While checking and replacing the fuel filter, also carefully check and replace the fuel pressure regulator hoses and the "F" fitting in the upper intake boot as any vacuum leaks in these hoses and fittings can also contribute to Lean conditions possibly leading to the CEL lighting. Please note that this "hose" that is connected from the F connector in the upper intake boot and to the fuel pressure regulator on the majority of these cars is NOT a vacuum hose. This hose typically does not have manifold vacuum for most models, this "hose" is nothing more than a filtered Atmospheric reference for the fuel pressure regulator. For most of these models, if you present manifold vacuum to the fuel pressure regulator, the fuel pressure will be reduced by approximately 10 PSI at idle and will lead to driveability problems and Lean codes.

What seems to be happening a lot lately is folks are not replacing their fuel pumps as a PM item, they are getting stranded, requiring tow jobs and/or dealer or rush fuel pumps to be purchased of up to $400+. Some even have to pay for the install as they do not have the tools on hand or the time.

These pumps are very easy to replace, only need a few basic tools and you do not even need to get under the car. Even if you buy the pump and do not get it installed, keep it in the trunk with the tools to change it and a copy of a DIY until you get around to actually installing it.

It is almost as easy as changing a tire!

So these fuel pumps are kind of like death, taxes and the cooling system.

As the Nike commercial says, "Just Do It!"

Your wife, kids, girl, buddies, employer, wallet and your schedule will all appreciate a PM fuel pump job.

www.bmaparts.com seems to have the best pricing on the fuel pump, not sure about the relay and filter?

I think there is also an online discount code that may still be good, something like SpecE30?? If I find it, I will edit this post with the discount code, but I do not guarantee it will work.

UPDATE: The BMA online discount code is SpecE30. Reports are the replacement pump is under $108 with free shipping. NOTE: As of Aug 2012 it appears the pump prices may have increased slightly to closer to $120?? As we are 5 years after this thread was originally written, the Simens/VDO fuel pump and sender assembly has gone up in price, as of mid 2017 the typical going price is around $145.

To help out people that are in fact in a bind and stranded, many of the local auto parts stores are reboxing and offering the Siemens/VDO pumps but they tend to be more expense that you could proactively purchase the part online when you are not stranded. Any example is this thread where it was found that the part was reboxed for a local suppler - https://forum.e46fanatics.com/showthread.php?t=1130362

Members here have had decent luck with Bosch branded fuel pump and sending unit assemblies.

A note about purchasing very low cost fuel pump sending unit assemblies, recently a number of members have purchased from Amazon or ebay pump and sending unit assemblies for as low as $50 and installed these as PM replacements for the original working fuel pump and have quickly found themselves stranded or with driveability problems. Just use your head, how do you justify a fuel pump sending unit assembly that is the cost of the typical fuel filter for these cars that has effectively no moving parts, not electrical components and no wiring. Think about it before you decide to be penny wise and pound foolish and trying to spend less that you would expect for a quality part. I DO NOT suggest you even consider spending less that $140 for a name brand part, this still does not rule out that you could still end up with a counterfeit item. Make sure you are buying parts form a reliable source and supplier. When something is too good to be true there is usually a reason.

Note about soft failures on the fuel pump

Some of the fuel pumps are soft failing. This means they work and you do not have issues starting your car, but they can cause intermittent hesitation, misfiring, stalling as well as problems running out of fuel when the tank is about 1/4 full. This is due to low pressure and/or volume causing the siphon or suction jet pump that transfers fuel from one side of the tank to the pump side to not transfer fuel correctly. What happens is you still have fuel in the non electric pump side, but the electric pump side runs out of fuel. This usually happens with 1/4 of fuel showing on the gauge. The hesitation, misfiring and stalling is usually again to low pressure and/or volume from a weak fuel pump. Many have recently replaced their fuel pump & filter as preventative and found that they have crisper throttle response, better overall acceleration and sometimes a small inprovement in fuel economy, which was not noticed until the pump and filter were replaced. So there may in fact be some hidden benefits to preventatively replacing your fuel pump and filter.

Most of the soft failures are due to severely worn brushes and commutator and/or wear in the actual pumping section of the fuel pump. Think about this analogy. Fuel pump brushes and the commutator are like brake pads and the rotor. The difference is the pump brushes are under constant spring tension on the commutator, it is like you driving the car with the brakes partially applied. Brush and commutator wear is part of the normal operation of a typical DC brush fuel pump, therefore the fuel pump is consumable, similar to a starter motor, but the starter motor is not running the entire time the engine is running.

There is a lot of mis-information from fuel pump suppliers and multiple Internet sources about running the fuel level low in the fuel tank, this information is pretty much garbage. Same hold true for fuel contamination. When you are talking about any fuel pump that is failing beyond the warranty and/or after 8-10 years, these are all failing due to them being worn out. Pump run hours is the main factor in pump lifespan, not vehicle mileage.

Contaminated fuel could damage a fuel pump, most contamination is due to water. But for the most part if the fuel is significantly the engine will run very poorly or not run at all. Once the contaminated fuel is removed and/or diluted with fresh fuel, there is little chance this will cause an imminent fuel pump failure. But if the fuel pump is over 8-10 years old, it would be wise to replace the pump at that point in time.

Some people prefer to wait and replace the fuel pump when if fails, the problem is unlike a dead battery you cannot always get the car started with little time and effort and get the car to a place where you can get it repaired quickly and easily. You cannot always find a fuel pump 7 days a weeks and at most local corner stores. So a fuel pump failure can and will cost you a lot more time and money than say a weak or dead battery.


Fuel Pressure & Volume Testing

From the Bentley manual, following are fuel pressure and volume specs for anyone that happens to have a fuel pressure gauge handy and wants to test either the fuel pressure and/or volume. I have not tried this trick, but some have stated that you can use a regular tire pressure gauge to measure fuel pressure in a pinch. BE CAREFUL DUE TO FUEL SPRAY AND FIRE/BURN HAZZARD!!!

Note on most E46 except the M3 the fuel pressure tap or test point (Schraeder valve) is located on the front of the fuel rail under the upper fuel rail/engine cover. This upper fuel rail/engine cover will need to be removed to access this fuel pressure tap or test point.

On the E46 M3, the fuel pressure tap or test point (Schraeder valve) is located on the fuel pressure regulator block, under the drivers side floor board near the fuel filter.

On SULEV vehicles, I have not done a thorough investigation, however, expect the unexpected with these cars. These cars have the stainless steel fuel tank with the sealed fuel pump. This pump actually has 15 year/150k mile warranty and cannot be serviced without replacing the entire fuel tank assembly which I have heard is in excess of $6000!!! Note to self, if you have a SULEV car sell it before 14 years / 140k miles.

Fuel Pressure Specs Per Bentley
All engines except the S54 3.2L M3 - Fuel pressure 3.5 +/- 0.2 bar or 50.76 +/- 2.9 PSI
Residual fuel pressure after 20 minutes - Fuel pressure >3 bar or >43.51 PSI

Additional note/clairfication for the M52 (323/328 models). These models may utilize a manifold vacuum controlled fuel pressure regulator unlike the M54 (320/325/330 models). Bentley did not properly or clearly outline how to test the fuel pressure on the M52 (323/328 models) from my perspective. For the M52 (323/328 models) the 3.5 +/- 0.2 bar or 50.76 +/- 2.9 PSI fuel pressure is the stated spec, however, I would suggest checking the pressure with the vacuum line to the Fuel Pressure Regulator BOTH connected and disconnected. If the fuel pressure is tested with the engine running AND the fuel pressure regulator vacuum hose connected, the fuel pressure could be approximately 2.8 bar or 40 PSI IF the fuel pressure is actually vacuum controlled. Please make note of this clarification and report what behavior you see with the 323/328 models.

Unfortunately I do not have ready access for many 323/328's to verify if there is any vacuum present at the FPR. The 323 FPR hose is connected to the main body side port of the CCV and I know in a number of cases if there is vacuum present at the CCV main body side port. Not sure if this is with a good CCV or a failing CCV, but any sort of vacuum presented to a FPR will lower the fuel pressure even if it is a FPR that is designed just to have atmospheric reference like the 325/330 models. Might as well check this while you are under the hood checking the fuel pressure on the 323/328.

S54 3.2L M3 - Fuel pressure 5.0 +/- 0.2 bar or 72.5 +/- 2.9 PSI
Residual fuel pressure after 20 minutes - Fuel pressure >4.5 bar or >62.2 PSI

Fuel Volume Specs
All engines 1.12 liter (1.16 qt) for 30 seconds at 12 Volts or while crank


If your car dies on you with 1/4 of fuel, you can sometimes get it started again by adding a few gallons of fuel. But beware you will again likely run out again once the gauge shows 1/4 tank. This may get you going if you are stranded and buy you a bit of time so you can shop your parts and DIY the pump. If you access the Hidden OBC menu (Hidden OBC Menu - Check Voltage, Temp, Fuel Level - https://forum.e46fanatics.com/showthread.php?t=239619) you will be able to check the fuel levels in each side of the fuel tank. Note that most all BMW's have a kidney shaped fuel tank with 2 separate fuel level sensors and 2 fuel pumps, siphon/passive pump the drivers side (Left side), which rarely fails, and the primary electric pump on the the passenger side (Right side).

The way these BMW kidney shaped fuel tanks function with the 2 fuel pumps is as follows:

The electric fuel pump on the right side of the tank is constantly running and excess fuel is returned from the fuel filter/regulator back to the left side of the fuel tank. When the fuel enters the left side of the fuel tank if passes through the passive siphon pump and transfers fuel from the left side to the right side of the fuel tank. Once the fuel level drops below about 1/2 tank the left side of the tank quickly drains and all the fuel is kept in the right side of the tank. If you access the Hidden OBC menu you will be able to see the fuel transfer behavior and if you see the fuel level in the left side of the tank higher than the right side of the tank once stabilized, it is likely indicating a soft fail fuel pump. But also note there are also fuel level sending unit failures that can also show similar behaviors. Best to get to know your cars total average range using the trip odometer and then use this along with fuel level to determine when you may have to refuel and/or have a potential problem cropping up.

It is feasible that a bad, intermittent or dirty fuel level sender could lead to incorrect fuel level readings and the car to run out of fuel while the gauge still indicates fuel is in the tank, this is a rather rare situation. If you are tracking your distance driven per tank, you should realize quickly you are exceeding the typical distance per tank you would normally drive. From my experience to date, I have not seen many sending unit failures and usually the sending unit failures or the few instances a sending unit float gets fuel saturated, the sending unit usually under reports the fuel level rather than over reports the fuel level. Here is a good link with pictures of both sending units removed from the tank.

https://forum.e46fanatics.com/showthread.php?t=738747

As for actual fuel pump failures, there are many myths and ideas as to why and how the pumps fail. Also suggestions that the pumps are overheating due to running the tank low on fuel for extended times and possibly the pump drawing air from time to time. But I can say most of these suggestions are mostly myths. The fuel pump is a DC brush motor that is constantly running and circulating cool fuel. The failures of these pumps really have nothing to do with overheating but simple brush and commutator wear just like a starter motor for an engine. What is typically happening is the brush fail to make proper connection with commutator and fail to start. Most of the fuel pump failures tend to happen after the car is shut down, there appears to be a very low percentage of failures while driving.


Also a few helpful hints on fuel pump replacement -

1. Wiring Connector
Many people new to BMW's or German cars may not understand how to release the wiring from the fuel senders. The connectors have a slide release that is a bit tricky but will be clear once you study it for a moment.

See attached pictures of the wiring connector up close both "latched" and "unlatched"

Auto part Technology Wire
Tire Auto part Automotive tire Wheel Automotive wheel system
Wheel Auto part Tire Automotive tire Automotive wheel system


Pictures courtesy of Frank_E46


2. Make sure you install the gasket on the fuel tank opening lip and not the sending unit
. When you remove the sending unit, the round gasket may come out stuck on the sending unit or you may partially pull the gasket out of the tank when removing the sending unit/fuel pump assembly, however, you need to install the gasket on the fuel tank lip before reinstalling the sending unit/fuel pump assembly, there is a small grove in the side of the gasket that goes around the inside lip of the fuel tank opening. What I actually do is install the sender with the gasket loose on the sender, then once the float is inside the tank, I then put the gasket on the tank lip before seating the sending unit. Also be VERY careful to install the gasket the gasket in the correct orientation when you install it on the edge of the fuel tank. This gasket is asymmetrical and should only be installed in the proper orientation. I believe there is the word "TOP or UP" embossed in the fuel sender gasket. If you install the gasket upside down you will have a fuel leak. Fuel leaks will only likely occur at 3/4 tank or higher. Once below 3/4 tank, you will likely not have any leakage.

If this gasket is not installed properly you may have also have Evap codes triggering as well as anything from a large fuel leak, to just a heavy odor of gasoline.

So be warned, make sure you note the orientation of the fuel sender gasket when you remove the sending unit/fuel pump assembly and reinstall the gasket in the correct orientation and make sure the gasket is fitted inside the tank opening and groove in the side of the gasket is installed on the edge of the fuel tank opening.

3. Fuel level can be an issue. If you are 3/4 tank or below you are in pretty good shape, but if you just filled up and need to change the fuel pump, you will have a problem with fuel spilling out of the tank onto the top of the tank and the driveway or asphalt below. Remember gasoline is not only flammable, it can soften asphalt and be an issue if you happen to be indoors. It is apparently very hard if not impossible to siphon fuel from the tank via the fill pipe, so be forewarned and this may be another good reason to proactively replace your pump on your schedule and not the cars schedule!

4. Be careful about residual fuel pressure in the fuel line before changing the fuel pump or filter. If your pump failed and your car will not start, you likely will not need worry about residual fuel pressure, however, if the car still runs and you plan on changing either the fuel pump or fuel filter, it is wise to remove the fuel pump fuse, start the car and let it idle until it dies. If you plan on removing the fuel pump, you can disconnect the wiring connector to the right side fuel sender and start the engine and let it run until it dies. NOTE, if yo disconnect the fuel sender, you may end up with some trouble codes for the fuel sender and you fuel level and mileage figures may be WAY off until you fill the fuel tank. The trouble codes will not likely show up with a standard ODB scanner, however, INPA, SSS or BMW Scanner may read these errors. Just make a note if you do run the engine with the fuel sender disconnected in case you see any codes, you likely forced them to be triggered. This is way you can pull the fuel filter or pump without a high pressure spray of gasoline. You will still likely get some fuel leakage, but hopefully not under pressure. It might also be wise to remove the fuel filler cap to also release any residual pressure in the fuel tank, but suggest you reinstall the cap before removing the fuel sender/pump combo.

Additionally I have no hard data, but it appears the 2002 and newer cars may have more of an issue with the pump life as compared to the very early E46's? Also case in point, many of the newer turbo BMW 3 series have had a series of fuel pump failures while most of these cars were still under warranty. So just making the comment that the pump design can possibly influence life expectancy.

Do not say you have not been warned!

Denial is not an option, as you will get a rude dose of reality.

Wanted to update this thread with some failure mode information.

These fuel pumps are all dying due to worn brushes and commutators, very little to do with contaminated fuel. Fuel contamination can accelerate fuel pump wear, however, the fuel sock is actually very fine and will trap or block all but the smallest particles from entering the fuel pump. Additionally almost every "fuel pump" at your local gas station has a large inline fuel filter that looks like a large canister oil filter. These filters trap quite a bit of debris that may be in the gas station in ground tanks or distribution lines. The fuel pump is a standard 2 pole/brush DC brush motor and the brushes and commutator wear out, probably faster than they should. This may be partially due to changes in fuel or fuel additives, but who knows for sure.

I took apart the pump that failed in my E46 at approximately 9 years with 84k miles. The brushes were shot and the commutator was HEAVILY worn. One brush was worn all the way to the copper stranded wire that is embedded in the end of the brush, about 1/2 way more worn than the other brush. I am guessing that the brushes were worn down by over 3/4 of their original length. Not sure if the uneven brush wear was due to the way the pump is angled in the sending unit or why this happened. In addition to SEVERE brush wear, the commutator was unbelievably worn, probably over 0.110" of wear or almost 1/8" diameter of the commutator was gone!

All the worn commutator copper and brush carbon is probably part of what ends up in the fuel filter and may be some of the black color that many find when changing the fuel filter.

On to fuel pump longevity.

Overall vehicle mileage or age has VERY little to do with the pump life expectancy. Keep in mind for every second the engine is running, the fuel pump is running as well, or just slightly longer if you consider the fuel pump priming. Pump run hours and the total number of pump rotations is what actually determines when the pump will fail.

It is assumed the pump life is around 5000-6000+ run hours, but this does not seem to match up very well with the failures we are hearing about. You could possibly tie this run time to mileage, bit is VERY hard and not very accurate. I am sure someone may challenge my info here that may be a Product Engineer with system life expectancy calculations. All that being great, but I think there is enough real world data to show that the majority of these fuel pumps are lasting around 4000-5000 run hours. Maybe the design life was longer, who knows. But the failure rate is pretty high over the past few years for E46 fuel pumps.

Estimating fuel pump life expectancy, you typically have 2 primary kinds of vehicle usage. There may be some middle ground, but the middle ground is based on the 2 primary vehicle usage profiles. Highway Warriors that can put 20+k miles on the car a year and the Urban Dweller that might only get 12k miles or less on the car a year seem to make up the main building blocks of vehicle usage.

My E46 is clearly an Urban Dweller. It probably averages about 90 minutes a day driving, possibly a bit less. The fuel pump in my E46 failed around 84k miles as I recall at around year 9. Doing the math, 90 mins x 365 days x 9 years/60 (mins in an hour) = 4927.5 run hours on the fuel pump! Notice I did not factor mileage in the equation at all because mileage has little to no bearing on the run hours. If I was to calculate the Average MPH over the 884k miles, with the data above, this works out to 17 MPH average speed for the life of the vehicle. I think in reality using the Trip Odometer most of the time, the Average MPH was usually around 22 MPH for the type of driving the car sees weekly. 22 MPH Average Speed may actually be yielding more along the lines of closer to 4000 hours of run time, which in the big scheme of things in NOT very reliable and not a very long life expectancy for a fuel pump.

I think most observant people would see a Highway Warrior could clock up far more miles in the same 5k hours if the cars speed was averaging 30-40+ MPH rather than the 20-22 MPH that my E46 would run.

So for instance, a real world situation I deal with weekly is I have a trip during the worst part of the day for traffic. I drive 12 miles and it takes me 1 hour. So this means I am averaging 12 MPH for this trip! Not very good a all and remember for each trip like this, I am adding 1 hour of run time on the fuel pump as well as other parts of the vehicle to go only 12 miles!

For the person that had a garage queen that is 10+ years old and has 50k miles on it, I would expect the pump to have a fair amount of life left because the pump probably has not seen a higher value of run hours.

There is some thought based on discussions that the earlier fuel pumps, pre- 2001 may last longer than the 2001-2006 fuel pumps. Not sure this has been proven with hard data, but this is a theory that is circulating around a bit.

But I think in general the fuel pumps in these cars should be replaced around year 8-9 if you expect to have reliable transportation. Some may disagree, just update the forum when your pump fails and you are left stranded. It is just a matter of time.

Links below to pictures of failed fuel pumps cut open showing the worn brushes and commutator. In both of these cases, the fuel pumps would not run on morning vehicle starts. You can see how thin the one brushes is where the copper braided wire was running on the commutator and also notice how severely worn the commutator is on both fuel pumps. The commutator material is worn over 1/8".

Fuel pump from a 2006 E46 with 84k miles that was used as a city commuter car that would never average more than 20 MPH per tank of fuel cut open to show worn brushes and commutator -

https://www.dropbox.com/sh/tdx5kech2h6mvha/AADAzsixZq5PcF63WsRmk2Pxa?dl=0

Fuel pump from an original owner 2000 E46 with 155k miles that was used for a primary car for the first 10 years of if the cars life, then the last 7 years this was a secondary back up car with very little miles put on it. Point is this car probably encounters close to 14k+ miles per year annually, mostly highway driving/commuting. So expect the fuel pump run hours to be about similar to the fuel pump above.

https://www.dropbox.com/sh/kh9u9n9i8rwklg8/AACwHq0lMDRoDMKKp3wNpu5Za?dl=0


A lower hour/mileage pump that was pulled from a parts car. Probably only a few years on this fuel pump. Note the minimal armature wear when compared to the failed pumps.

https://www.amazon.com/clouddrive/share/UsrpMxsDwZ1Wd4QRrxSjPgvy3QymuKhAnz1Bw9kbjub


Also a very interesting testing case and analysis of fuel pump life and impact of different fuels. Interesting that brush and commutator wear appears to be greater with gasoline than with E10 or E20 blends.

http://www.agweb.com/assets/import/files/e20endurance.pdf


Regarding all of the claims of not running the vehicle below 1/4 tank for fuel pump cooling, this is pretty much a bunch of BS. Most all modern electric fuel pumps have the fuel volume of fuel passing directly through the center of the fuel pump which actually bathes the commutator, brushes and bushings in fuel. So as long as the fuel pump has a supply of fuel, it is being cooled. Additionally I have yet to see a high mileage heat related fuel pump failure. I have cut MANY fuel pumps open for inspection and the majority of the BMW/German design fuel pumps that have failed had SIGNIFICANT commutator and brush wear and it was clear this commutator and brush wear was the root cause of the pump failure.

DC brush motors are CONSUMABLE and they have a designed or finite lifespan. Maybe they should be lasting longer than what we are seeing here in the real world, but like anything, the real world is what we all face on a daily basis. I think the side commutator/brush design pumps may wear faster than the end commutator/brush design fuel pumps.

Should listen closely from the 9 minute mark. I think the Airtex Director of Engineering should be a pretty reliable source. Far more knowledgeable the majority of "expert" mechanics which I have met VERY few of.

What is interesting is if you watch the video and listen to the discussion regarding the pump commutator and the overall issue of wear concerns, there is NO mention of motor brush wear. It may be due to the DESIGN of the end based commutator and the way the brushes ride on the end commutator. I expect that the end commutator/brush design is far more robust when compared to the side side commutator/brush design that the E46 and many other BMW and other German model vehicles use. There may be material differences as well when compared to the BMW/German design.

But for the BMW pumps that I have cut open, they ALL have significant brush and commutator wear and I have not found much problem with the actual pumping portion of the pumps, more often than not the pumps slow down due to commutator and brush wear and also fail to start due to extreme commutator and brush wear just like a worn starter motor that have have personally rebuilt hundreds of over the years.

https://www.youtube.com/watch?v=piOzN1tZI_E

https://www.youtube.com/watch?v=lMVvuME22M0&feature=youtu.be

https://www.youtube.com/watch?v=QbzEeWy1b3o
 
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#40 ·
Just recieved mine today, good project for after work. My coworker is letting me borrow his 330Cic right now, not a bad replacement.

It cracks me up how heated some people get about the PM threads. You want to wait until it fails, go ahead...if you want to keep your car from leaving you stranded replace it. To each their own. And Mango definitely doesn't say every other week, just every 60-75k miles...that's years if you drive "the average" 12k a year.
 
#46 ·
Nah, just good PM. If you ordered from BMA, call them and ask to throw the relay in. IIRC, its the first relay of the row of four.

http://www.bmwgm5.com/E46_Relays.htm

you'll have a bit of a time trying to fish it out but just stuff your fingers in there and wiggle the relay out while pushing on the release tab. it'll come out slowly but surely. Make a mental note on the way the relay is oriented so when you put the new one in, you'll have no problems pushing it back into place. it's easier said than done with all the wires down there but overall its a quick task
 
#48 ·
No the glovebox is held on by standard philips star head screws. Very easy to remove. replacing the relay actually takes longer than removing the glovebox.

By the way kudos to BMW on the E46 glovebox. extremely well made and fits together extremely well. Huge improvement over the E36 glovebox.. HUGE.
 
#59 ·
Patton,

As for a PM thread, check this link - http://forum.e46fanatics.com/showthread.php?t=923563

It is fairly complete, the only things that may not be in the first post are possibly the fuel pump/filter/relay and buying a 2nd key for the car.

We see time and time again, problems lately with fuel pump/fuel filter/relay failures leaving people stranded and/or with performance problems that linger on after much more money is spent on other PM type of items that could probably wait.

For example we see coils, VANOS seals, MAF's, DISA's, complete CCV's, valve covers and all sorts of other things sometimes replaced in an effort to sort idle and cold start problems. Many of these items are a problem and do cause issues, but would it be great if you replaced the fuel pump, filter & relay for less that just the cost of a MAF or many of the other stated repairs and it solved most of your problems and improved your cars reliability?

You need to triage these cars to help determine what should be replaced first.

As for the 2nd key, most used BMW's seem to only come with 1 key. Within a short period of time it seems like about 20%+ of the owners loss or lock their only key in the trunk. Then they are in panic mode and have to pay full pop at the local dealer for a key and have to wait for 1-4 days to get their key depending on when and where it is ordered from. So getting either a $60 replacement key or a $160 replacement keyfob should be very high on the list for new owners. Do not let the dealer sell you a $60 valet key when you can get a "master" key for same money that opens the trunk and glove box!

As for JOFJ, see the first link below in my signature or look very carefully under Mango's picture in his signature, he has 3 links, but they are not as pronounced as my links.

Some folks seem angry that I posted this, but my intention is to inform the community and make them aware that fuel pumps are problems and for less than $200 spent on your own time can head off a future problem, probably improve driveability and save you at least $200 and a lot of time if you replace the pump/filter/relay as a PM item.

Face it, there are only a few things that really strand these cars, fuel supply issues, crank & cam sensors (cam sensors are more likely to fail), intake boot failures (but they rarely strand your, but for $30 why not PM it, and cooling system failures.

Yes batteries are problems, but usually a jump or roll start may get you going, can't do much to really convince a fuel system problem to clear itself enough to drive reliably.

So it is not a bad idea to really reflect on what is important to you. If time, money and inconvenience is not important, then do not do any PM.

If you are a gambler, then at a minimum replaced your fuel filter and swap the fuel pump relay with the horn relay. Then you can decided if you should buy a pump and gasket for $110 and keep it in the trunk along with the tools, or wait and see if your car ever needs a pump?

My wife has an '06 E46 Vert with 60k on the clock. I need to decided when I pull the trigger. I think I should at least buy the pump and gasket now and have it on hand. My bet is if I have the pump on hand, it is like buying a snow blower, it will not snow that Winter! But at least I have it in hand and can put her on the road in 45 minutes. I will swap the pump relay as I would bet the horn has only been used about a dozen times in the car and the filter will be replaced soon during Inspection II next week that will be performed at no cost as the car has extended maintenance that the original owner purchased and was transferred when we purchased the car as a CPO.

It is well worth the small expense in my household for peace and tranquility not to have my wife stranded and upset at the car and me!! If she knew I had her sitting on the edge of a limb for less than $200, she would have my jewels in a vice!! So I will likely be placing my BMW pump order very soon!

As they say YMMV, what you choose to do is up to you, I just wanted to point out my observation and views and how I will likely handle my own situation.
 
#60 ·
142k, 11 years and 10 months, no issues. I got this one, its only the motor and filter,

<table style="width:auto;"><tr><td><a href="https://picasaweb.google.com/lh/photo/BupOl1hquRkVDRpN1PXHD9MTjNZETYmyPJy0liipFm0?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/-ohyP0Qia4_A/T-rvrpcbCdI/AAAAAAAAB6w/JsnQFhN_JTc/s800/f0986580132.jpg" height="200" width="200" /></a></td></tr><tr><td style="font-family:arial,sans-serif; font-size:11px; text-align:right">Van <a href="https://picasaweb.google.com/cornflakes.vigilante/DropBox?authuser=0&feat=embedwebsite">Drop Box</a></td></tr></table>

It's going in tomorrow, along with a new fuel filter, sparks, complete cooling system and doing an electric/mechanical fan swap/upgrade at my DiY Garage :)
 
#61 ·
Not clear about 1998-2000 models, they may have had different/better quality pumps? It would be interesting to see the stats on that.

But for the 2001 & newer cars, it seems the failure rate is much higher.
 
#62 ·
I was looking at the Bentley yesterday checking for info on the relay and according to them the MS45.1 ECU doesn't use a fuel pump relay. They say the fuel pump module handles that function. But they also said the MS45.1 was only used in (IIRC) the 2002-03 325i and 325Xi.

I thought the MS45.1 was the ECU that was used in the ZHP. Anyone know for sure if the ZHP has a relay?
 
#63 ·
AFAIK, MS45 should be 2003 and up 325 AND 330 (of course, including ZHP) and I highly doubt it doesn't have a relay otherwise there'd be a different part#/spec for the non-M fuel pumps and to my knowledge, there's not. Pop your glovebox and have a look.
 
#64 ·
Not sure about the ZHP, however the M cars may be different??

I have not looked closely at an E46 M car, but my E39 M5 has what looks like a relay, but it is not one. It is called a ETK module or something like that and is all electronic. The pump is PWM controlled from what I understand? Has something to do with fuel delivery at higher RPM under load and the E39 M5 lacks a fuel return from the fuel rail, it returns at the regulator.

It is possible the E46 M cars are similiar?
 
#69 · (Edited)
The way I see it, E46Mango is just pushing everyone to do the maintenance he recommends simply as reassurance. And even if you don't take what he says in the first place, he knows that it'll come back one way or another down in the line since you all clearly care enough to post in the thread. Too much of anything gets annoying and we all know that, but the given fact is that the number of threads people post up here that are in relation to their cooling systems catastrophically failing, cars not starting, and so on simply outweigh these 'safety precautions' (for lack of a better phrase) that E46Mango, jfoj, dmax, etc. go around posting, trying to help out the many members of the forum. The sarcasm may not be completely necessary at times, but when you take into consideration how many times these guys have to type the same thing over and over again.. You may as well want to have a little fun doing it. Just the way I see it, as you guys are taking some of this stuff way too personally. Not biased in any way.
 
#73 ·
just to add to this thread(not threadjack). anyone thinking of changing their fuel pump that does spirited driving may consider at the same time adding in the oem M3 fuel pump baffle. yes the E46 already has a very small baffle built into the fuel tank. but the oem M3 baffle is like a little baffle/cup that holds a little gas directly at the pumps pickup. i had it on my previous E46 and for only ~$15 may be something some may want to do while doing their pump. it will absolutely have no adverse affects and could only aid fuel for the pump in any situations.
Fuel Baffle Fixture 16 11 2 229 656

http://forum.e46fanatics.com/showpost.php?p=12126895&postcount=15

http://forum.e46fanatics.com/showpost.php?p=10628923&postcount=5
 
#74 · (Edited)
Going to say this once and then be gone...

There are many people on here with 3x the mileage of Mango's 60K service interval on their original fuel pump and doing just fine.
If you want to have peace of mind and spend the hour or 2 to replace a pump twice (total time) and the roughly $250 that takes that is up to you.
For me with CAA and them willing to tow me up to 200 kms it is not mathematically worthwhile to replace the pump until it fails, or shows signs of failing, which it has not.

It is up to the individual, but to say that changing it proactively saves the person money is no more true than saying wait until it fails, both could hold equally true, and in my case as well as many others who have given mileage totals on original pumps, we're saving money by not doing it as a PM item, especially at 60K miles.

PS I'm a technician so saying this is shooting myself in the foot and giving me less work, I also hold an economics degree so don't worry, my math pans out. Up to you whether to trust me or not. I really don't care, but in an era of overspending and lack of savings by young people (we can all agree that runs rampant on here) I would rather you save your money.
 
#79 · (Edited)
Going to say this once and then be gone...

There are many people on here with 3x the mileage of Mango's 60K service interval on their original fuel pump and doing just fine.
If you want to have peace of mind and spend the hour or 2 to replace a pump twice (total time) and the roughly $250 that takes that is up to you.
For me with CAA and them willing to tow me up to 200 kms it is not mathematically worthwhile to replace the pump until it fails, or shows signs of failing, which it has not.

It is up to the individual, but to say that changing it proactively saves the person money is no more true than saying wait until it fails, both could hold equally true, and in my case as well as many others who have given mileage totals on original pumps, we're saving money by not doing it as a PM item, especially at 60K miles.

PS I'm a technician so saying this is shooting myself in the foot and giving me less work, I also hold an economics degree so don't worry, my math pans out. Up to you whether to trust me or not. I really don't care, but in an era of overspending and lack of savings by young people (we can all agree that runs rampant on here) I would rather you save your money.
Next time you see teenager blow $50 on racing stripes, $1,200 on LM reps, or $100 on AEs, I hope you speak up then ;)

Yet when the mango or fjoj spend that money on a fuel pump, it's considered "overspending".

Also remember just cause your pump "works" does not mean it's putting out adequate volume and pressure. Same especially holds true for the fuel filters. Those lean codes and rough starting you could never figue out? Surprise surprise. :shhh:

And BTW I don't think I ever said 60k for the pump. As JFOJ said, it goes by hours. Typically 10 years is when they start to go bad. The filter... 60k definitely.
 
#77 ·
I believe in preventative maintenance just like mango, my brother is on his 3dr engine he does not. My car is 95k and it looks and runs new but I have spent tons of money to make it look that way or keep it looking new, I dont have a nothing degree but my math adds up anyway you add it.

Sent from my SCH-I405 using Bimmer App
 
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