BimmerFest BMW Forum banner

Injectors replacement and/or servicing DIY (E39)

181K views 79 replies 31 participants last post by  Bmwe39528i 
#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.
 
See less See more
22
#3 · (Edited)
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
 
#6 ·
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?
 
#7 ·
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?
 
#9 ·
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.

 
#11 ·
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 ....)
 
#18 ·
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.

.
 
#21 ·
in reality how many of us replaced these injectors ?
I have a whole series of repeatable lean-misfire codes:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

One of the items near the end of my list (after replacing things like vacuum hoses) is to check the fuel injectors.

I also borrowed the Autozone Actron CP9920A, which, I hope, will help (if it's fuel pump or fuel pressure related):
 
#22 ·


The mpg got better over the last 3-4 fill ups. So who knows? It looks better to me. Also, when I cleaned the "receptacle" (the place where the pintle seals with the O-ring in the intake), 2 of them had bad grit/fine sand/dust which makes me believe it was sucking air right there. It was also a bit hard to clean - these were the last 2 close to the firewall. The other were just dirty, and I wanted a good seal on the O-rings.
Concerning the fuel leak, I don't know yet. I wait untill the big deep freeze-up hits. Then I will know for sure. If no more fuel smell, then I'm golden.
 
#23 · (Edited)
doru said:
one is responsible for a lean condition, the other one will leak fuel
I'm trying to identify all sources of lean mixture conditions, which means identifying all vacuum hoses, tubes, pipes, and encaps in addition to intake manifold and fuel injector o-rings.

Looking in Realoem for my 2002 M54 for the o-ring part numbers, I find this diagram:

I'm a bit confused which six o-rings to replace; would someone confirm which of the following o-ring sets it is recommended to replace?

  • 04; O-ring; 7,52X3,52; Q=6; PN=13641437487; $3.75
  • 05; O-ring; 9,2X2,8; Q=6; PN=13641437486; $3.75
Of these two o-ring sets, is the thinner o-ring the one that will cause a vacuum leak and the thicker o-ring will cause leaked fuel?

 

Attachments

#25 ·

I'm trying to identify all sources of lean mixture conditions, which means identifying all vacuum hoses, tubes, pipes, and encaps in addition to intake manifold and fuel injector o-rings.

Looking in Realoem for my 2002 M54 for the o-ring part numbers, I find this diagram:


I'm a bit confused which six o-rings to replace; would someone confirm which of the following o-ring sets it is recommended to replace?


  • 04; O-ring; 7,52X3,52; Q=6; PN=13641437487; $3.75
  • 05; O-ring; 9,2X2,8; Q=6; PN=13641437486; $3.75
Of these two o-ring sets, is the thinner o-ring the one that will cause a vacuum leak and the thicker o-ring will cause leaked fuel?


Bluebee, once you remove the injectors, you would want to replace BOTH O-rings.
In my case, injector # 6 and injector #5 (close to the firewall) had the "receptacle" - for lack of words - all filled with sand-like dust & crud. Here is the pic, the Q-tip I used to clean the "receptacle" - it's the hole where the injector seats with the pintle:



The mpg went slowly and steady down over the last year and a half. After I changed O-rings (and actually injectors) the mpg is back up where it should be. The fuel leak you will experience ONLY when it's bittercold, and the engine did not have time properly warm up - and I mean the whole thing under the hood, not just around the pistons. Also, that pesky fuel leak due to faulty injectors is only for the M54B30 engine- the 3 liter one.
But the vacuum leak due to worn out O-rings anyone can experience this. Also, in time, on top of the injectors is a filter that gets clogged up. This filter and the tiny deposits (in time) inside the injector will alter slightly (or more if really bad) the air-fuel mixture.
My advice is after 100 k miles to pull out the injectors and go to a reputable place that cleans (mechanically) the injectors. They "should" ultrasound and chemically clean them, re-calibrate the nozzle pattern and replace the O-rings & filter. Also a detalied report should accompany the repair. This report will give you the details of before & after cleaning flow % of each injector as well as the spray pattern. That sheet is pretty detailed.
 
#27 ·
Why would you do that (replace only 1 O-ring)? Once the injector is removed, you can access both O-rings. I would not do a 1/2 job. Also, the "rebuilding" of an injector consists of:
-replacing both O-rings
-replacing the filter (it's on the top, you could remove it, but you can also destroy the injector if you don't know how - some people advise removing it with a wood screw, and I am against: chance to destroy the injector are too big)
-cleaning and re-calibrating the injector.

The report we got from our injector cleaning facility is similar to one you posted, only in more detail.
The downtime for any customer at that specific facility is 1 day max. which is reasonable (here in Calgary). One can book an appointment, bring them in in the morning and pick them up in the afternoon.

Also, FYI, if you bring the car to the dealership for Service II, cleaning of injectors & engine is included in this. It's a chemical cleaning performed with something similar to Techron I think (Lubro-Moly chemicals). How do I know? I had it performed on my car in 2008. They also tell you NOT to fill up until you almost empty the tank.
 
#28 ·
Why would you do that (replace only 1 O-ring)?
I don't know. I'm asking you! :)

My 'thought' was that I was only trying to identify & resolve 'vacuum leaks' (I don't have a fuel leak); so if I only wanted to solve a vacuum problem, I'd only replace the vacuum o-ring. At least that's the 'why' for asking the question.

If it makes no sense to just replace one o-ring, then I guess, the procedure is this:

a) Do the water-and-the-straw trick to identify a vacuum leak at the thin FI o-ring.
b) If you 'do' have a vacuum leak, then replace BOTH o-rings

Does that sound reasonable as your recommended procedure?
 
#29 ·
I would service the injectors @ 100k miles by replacing both O-rings, and have them cleaned at a licensed facility (mechanical cleaning, re-calibrating & new filters). The ensuing report will also tell you IF there is any injector beyond repair.
If you have no driveability issue, there is no sense opening everything up only for curiosity sake, or doing a half job. You can mess up more things then doing any good.

0.02
 
#30 · (Edited)
If you have no driveability issue, there is no sense opening everything up
Depends on what you mean by a 'driveability" issue.

I have early morning misfire codes (lots and lots of 'em) all due to lean conditions.
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

The driveability is fine when warm; lousy when cold.

BTW, with these codes:
P1083 BMW 202, Fuel Control Limit Mixture Too Lean (Bank 1 Sensor 1)
P1085 BMW 203, Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)

Given:
Bank 2 is cylinder 4, 5, and 6. Those are the rearmost 3 cylinders.
Bank 2 sensor 1 is the pre-cat O2 sensor for the rear 3 cylinders.
I'm going to look up why one oxygen sensor reports on both the front bank1 and the rear bank2 sets of cylinders (I had initially thought there were two oxygen sensors, pre cat).
 
#31 ·
Doru, thanks for putting this together. I'm currently under going the surgery but diy'ing the cleaning by letting it soak in carb cleaner (berrymans b12) over night. I will pulse it but only to let some solution through it in reverse. I bought the injector rebuild kit from Mr Injector on eBay for $25. THis is probably my last attempt at solving my probs before I give up on my own googling and the Indy and take it into BMW.

I've got a strange one which is BMW 235 & 236. Both banks too rich. The P1092 & p1093 paint a different picture however as that translates to Bank 2 is rich AND lean. Go figure!

Bluebee - does John treat you to dinner and Babysit for you? Because you really are THE most valuable member of this forum. I have yet to see anyone as dedicated and as good at what you're doing on any other forum. Keep up the good work, we all really appreciate it!
 
#32 ·
Bluebee - does John treat you to dinner and Babysit for you?
I don't know who John is (presumably a forum owner?) but we're all working together toward a common goal.

Each person contributes depending on their strengths - and the other team members make up for their weaknesses.

My strength is NOT in knowledge (I know less about everything than anyone until/unless I have the problem myself).

My strength is in documentation. Everyone else contributes in knowledge.

It works because we work together as a team!
 
#34 ·
Confirmed - the injectors were faulty

It's confirmed that my old injectors were faulty.
This morning it was very cold. The original injectors would start leaking at this temperature, and I would have that raw fuel smell in the cabin about 3-4 minutes after driving. No more of that :AF330i: and I am soooo happy!!!! Expensive but very easy repair.
 
#36 ·
The weirdest hing happened. Over a quite longer time span, the fuel economy ever so slowly improved. From about 13.5 - 14 l/100km (17 - 17.4 mpg) to right now 11.1 - 11.8 l/100km (19.9 - 21.2 mpg). All this is exclusive city driving, no Hi-way. Haven't touched any rubber hoses, boots, CCV etc. (no codes either).
Runs normal, is all I can say. Hope it stays that way and I don't jinx it. :)
 
#37 ·
From the "other" forum, a very good piece of information:

"Thanks for all the posts, and sorry for my delayed response...Snow storm and no power for the last 5 days. I let the car sit over night with everything together and vuala...no leaking...but i think it was the lack of lube lol...I had mine rebuilt because i was troubleshooting a misfire, that turned out to be a blown valve. I had a report taken, all of injectors have a 22% flow obstruction, and one was 35% @ wide open throttle...The guy said, anything over 10% could cause misfire and poor performance and rough idle.

and now after the rebuild, no obstruction of flow, and the car runs better than when i bought it. 140k miles ago."

Here is the post
 
#41 ·
How common is an injector failure?
If you had to put a mileage on it, when would you replace them as prev.maint?
It's a $600 DIY, so what's the final word on simply cleaning your injectors? Better bang for the buck?
It looks like the 3 liter M54 OEM injectors have issues, and in cold weather only, you will see this happening. They leak somwhere at the mid-body. It's a manufacturing defect. The new Siemens ones are OK (or so I heard). If you don't have problems, don't do it. If you smell raw fuel in the cabin a few minutes after a cold startup in cold weather (the temp has to be below -20°C - this is below -4°F), and if you open the hood you see a big cloud of fuel vapors coming out from the fuel rail, that's it. You need new injectors, no if's and why's. The car can catch-on fire anytime.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top