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Discussion Starter · #1 · (Edited)
Before getting into it, here is some background:
1.) Over time, the injector O-rings just like almost any rubber, will deform, loose elasticity, change some its properties. Some effects are deteriorated mpg (for some), or fuel leak for others. The lower mpg (I experienced it too) is due air geting sucked in - just like a vacuum leak. This can be tested with a COLD running engine (in the morning, first key) and some carb cleaner - spray it around the fuel rail, and if there is a rpm surge, you found it. Very simple. When the O-rings are gone, one is responsible for a lean condition, the other one will leak fuel (I thought I had the latter, but it wasn't true). If fuel leaks, or if you lose mpg due to injectors absorbing air (lean situation), new O-rings are the cure.
2.) For the M54B30 (applies to e39 530, e46 330, X5 3 liter, z3/z4 3liter)engines manufactured I believe up to 2006, there is another issue. It's the injector himself. It seems that the batch of Siemens VDO injectors for this particular engine will deform over time (ever so slightly), allowing the fuel to mist under the hood through the fuel rail, when the car is started in cold weather. The condition is a cold engine and temperatures below -20°C (the car does not need to be parked outside, it's enough if the garage has the temp around 0°C - 2°C). Raw fuel smell will waft into the cabin a few minutes after starting to drive under these conditions. I witnessed myself the fuel mist/vapours coming out of the fuel rail. It's scary, because the engine has all kinds of electrical gizmos, and a small spark can be the end of the car's life (and maybe the driver too). I tried changing the O-rings, but it did not do the trick - I still had the raw fuel smell at cold starts and cold ambient temps. The mpg started to get back to normal though. Then I found out that BMW had an internal bulletin concerning those injectors, and there is a new batch of Siemens VDO injectors that apparently do not exhibit the deforming issue. This happens only when it's real cold, and the z series is driven mostly in warm weather, and until not too long ago, even the e39 were stored during winter (not me). More 330 had this issue, and lately the X5 with the i6 engine.

So here we go:

If you have a lean situation (mpg will start going down ever so slightly, but steady), you will need O-rings:



If you live where it's cold in the winter, and the O-rings didn't help, you need the improved Simens VDO injectors:





Remove the beauty cover (10mm). You will see the O2 sensors wires, just pull them out from the clip, set them aside, then pull the retaining clip out:



The next step is to take off 2 electrical connectors - one in front (vanos side), and one in the middle:





Now, you need to take off the long electrical connector box. This is where I had trouble, because the retaining clips are upside down, and very hard to take them off. After about 3-4 unsuccessful attempts, I figured it out. This is how they look:



Just slide one end/hook of the clip down (you don't need to take the whole clip out - that's the ticket)- here:





The last 2 electrical connections (close to the firewall), you have to slide the back side of the clip, the front side is in the way of the fuel rail skate where the screw is attached. And finally the electrical box comes out with a slight tug:



Now, before you take the fuel rail off, you need to relieve the gasoline pressure. There are 2 methods:
One is to use compressed air (if you have a compressor), set the compressor to about 30 psi max and give a short burst of pressure inside the front valve (take the cap off, and it will look similar to your tire valve stem - and works the same).
Another method is to use a small screwdriver and press the valve - fuel will come out, but not too much. Just wrap some rags around to contain the little gasoline that comes out - below are the pics:







Now you are ready to remove the screws. A good idea would be to use a magnet, because they can slide out, and fall in the engine bay, and not retrieve them anymore:





Once the screws are out, pull up on the fuel rail, and there she goes:



To take out the injectors and either replace them entirely, or only the O-rings (I would also go to a specialized shop and re-calibrate them. About 140-150 bux for 6 or 180-200 for 8. Including new O-rings, new filter and cleaning - with a detailed report), you need to pry off the retaining clip:







There is enough room on the fuel rail without needing to pull it out from the fuel line, so just pull out each injector. Here are side-by side new and old. They have different numbers stamped on them, they are very small (on the other side though):



And once an old one is out, replace with a new one:



I also cleaned the injector receptacle - it was really dirty:



Make sure you don't loose the q-tip inside the fuel chamber. Then align as close as possible the new (or old and serviced) injectors and push them together with the fuel rail in - start at the cowl (firewall) end, and work your way to the front of the engine. You might need to slightly use some force (short, sharp shock with the fist on top of each injector) to slide them in. The rest is the same as removal in reverse sequence.

Have a fire extinguisher handy, and I am sure you know you are responsible for your own doing.

Good luck


P.S. I forgot to mention: tightening torque of the bolts to the fuel rail is 10 Nm or 89 inlbs.
 

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I will add to the bestlinks so others can find this easily in the future.

Here's what is in the bestlinks if I search for 'injector' before doing so:

After reading each, I find none of those are really relevant to this DIY so I'll ignore them for now.

Doing an E39-only title search for "fuel injector", I find only 16 threads surfaced, the following five of which may be promising as additional information:

  1. DIY: 530d fuel injector
  2. Fuel Injector Service
  3. Fuel injector flow balancing ?
  4. Fuel injector cleaners?
  5. fuel injector cleaning
However, looking at those threads, the first is for a diesel; the second discusses Witchunter Performance & Dr Injector servicing (much as in this "Decent Techron thread"); the third mentioned Bosch injectors; the fourth talks about fuel-injector cleaners as does the fifth. Therefore, none of them are particularly useful for an injector removal & servicing DIY.

Doing a google search for "bmw e39 fuel injector DIY" doesn't net all that much either ...

Neither of which was particularly useful.

This unexpected dearth of BMW E39 injector replacement & servicing DIYs makes this one the first that I would put in the bestlinks:

- How to replace and service your BMW E39 fuel injectors (1)

EDIT: I also cross-referenced to this thread:
- How to diagnose a sudden and disturbingly unsettling cold-engine misfire
 

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Great work up Doru,interesting that BMW knows of this problem but not going to do anything to help owners make the fix. Will be watching intently for your next post on how the car is operating with the new injectors installed.
 

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Discussion Starter · #5 ·
Great work Dorin. Any noticeable throttle response or MPG savings? Or too soon to tell?
Every time I wash my car, it seems faster :)
I have to wait, just drove to work this morning, started up at the first key, no problem (I didn't expect any).
Seems the same to me so far, but for ECU to re-map, it will take a while, no?
 

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Nice job doru!

A few comments:

1. What was the condition of the O-ring when you removed? Was it brittle and fell apart or just stiff?

2. The Fuel Injectors....I wonder if you go this far to remove the fuel injectors, maybe it is a good idea to send them to a shop to do ultrasonic cleaning?
 

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Nice job doru!

2. The Fuel Injectors....I wonder if you go this far to remove the fuel injectors, maybe it is a good idea to send them to a shop to do ultrasonic cleaning?
Not sure there is a reason to do this. Doru got new injectors as the old Siemens have a flaw of deforming while that flaw was supposedly fixed in the new design.

Why spend the money to clean flawed injectors?
 

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No,

I am talking in general for others to see. Let's say your injectors are OK but the O-ring is bad.
Then replace the O-ring, but since the injector is out, one may as well clean it? Just a thought.
 

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No,

I am talking in general for others to see. Let's say your injectors are OK but the O-ring is bad.
Then replace the O-ring, but since the injector is out, one may as well clean it? Just a thought.
I see. Well, IMHO the only advantage I see to sending it out is flow matching or for those worried about damaging the injectors.

Otherwise, there are plenty of DIY injector cleaning videos on Youtube with great success in just cleaning it. As you know, it's just about removing the carbon buildup. Ultrasonic just breaks down the hardened buildup quicker than the DIY method. This video looks like something you would probably use in your garage.

 

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This is the kind of DIY write-up I like. Deserves to be moved to the DIY section. Given that the M52TU in my car shares a lot with the M54 series engines, I'm wondering if BMW utilized the same flawed injectors. The replacement O-ring parts appear to be for the same Siemens units. (I'd better go check up on this ....)
 

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Discussion Starter · #13 ·
Nice job doru!

A few comments:

1. What was the condition of the O-ring when you removed? Was it brittle and fell apart or just stiff?

2. The Fuel Injectors....I wonder if you go this far to remove the fuel injectors, maybe it is a good idea to send them to a shop to do ultrasonic cleaning?


Cam, I might have a more elaborate answer. But I will try to keep it short.
The condition of the O-rings was OK because they were changed in February this year - I was chasing a vacuum leak I could not find (mpg was decreasing ever so slighly month-by-month since last summer, and I had no idea where the leak was). I also had the raw fuel smell and had to do something. After I changed the O-rings, the mpg stabilized, but m=not the fuel smell - I had a bad leak when it was cold - a big cloud of gasoline vapors (visible) under the hood at the fuel rail. When the engine warmed up (after driving about 10-15 minutes in he morning commute), the rubbers and everithing else expanded, and there were no more leaks. The problem is we have the alternator and other electrical gizmos under the hood, and all it takes is a little spark.
At the beginning of my post I mentioned that this DIY applies whether you change injectors or if you clean the injectors /change O-rings and the little filters inside the injectors. It's the same procedure. That's why I posted the pic with the O-rings. Has the p/n on them. I mentioned the rates of a good shop, because I looked into it. They will clean mechanically the injectors, re-calibrate them for flow and replace the O-rings and the filters. Then they will hand you also a report with the flow % before & after cleaning and also the spray pattern report. Done that on a friend's car with the v8 (also BMW). He had 2 injectors flowing less than 30% or so. And the spray pattern ws all messed up on almost all of them. He had roughly 130 k miles on the car. But no fuel leaks. The O-rings were bust.

On a side note, when I placed the the top and bottom protection cap that came from the new injectors onto the old ones, they slid on very easy, no resistance at all. They will probably fall off if you tip the old injector with the new cap. On the new injectors, both caps were a bit snug. The pic below:

 

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im interested in this injector cleaning... for a 2003 540i... is it worth it?... 120k miles, im sure its never been done... I also have a couple bottles of seafoam unopened sitting in my garage, should I bother with that stuff on a bmw?
 

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Discussion Starter · #15 ·
The new design injectors are the Bosch 3 design.
For the M54B30 engines it's Siemens, the new design.
Bosch does NOT carry them for my car. Maybe for yours?
Check this out , injectors do not come up for M54B30.
 

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Excellent writeup!

I'm not at the fuel injector comfort level yet but I am on the way. Scary to hear about the fuel misting under the hood.

My 530i is at 95k so hopefully I have a couple of years and by then I should be ready willing and able to tackle any DIY.

You pros are the nuke! Thanks for all of the useful info.

.
 
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