[Torqu3]

Let me start by saying both of these things have fantastic DIY guides already, so I have little to add, but there are a few things I learned that I think would be good to point out. I didn't bother with pictures because I had very little room underneath my car to do this, and didn't want to get my phone all messed up. SO here we go!

Fuel Filter:

Here is the Don't Fear the Fuel Filter(DFFF) thread that everyone talks about. This is what I used to get the FF done. The only things I have to say about this are:
1. The panel underneath the car you need to remove is closer to the middle of the car, by the exhaust. Not along the side like I thought it was. It's the same panel you'll have to remove in order to replace the transmission filter.

2. In the DFFF thread, Quasimodem mentions having to cut off a clamp. This is NOT the case. Don't hack up your car.

3. Please please please prime the fuel lines. I bought the Schwaben scan tool off ECS tuning for this reason and had to cycle the low pressure pump for 60 seconds before I stopped hearing air bubbling through the lines. I can't imagine the hell I would have put my car through had I just let it crank and crank.

Here is my step-by-step guide for this. Much less detailed than DFFF, but clears up the issues that I had.

1. Lift the car. You only really have to lift the front. I had all 4 corners in the air since I was going to do the Differential Fluid as well. The higher you can get your car, the better.

2. Remove the underbody panel that is in the middle of the car.

3. Undo the bolt that holds the fuel filter bracket to the car. This will make a little electronics box fall, just scoot that off to the side. Put a drain pan under the filter.

4. Undo the hose clamp on the fuel line at the front of the fuel filter. Pull the fuel filter out of the fuel line and let the filter hang into a drain pan. The front fuel line will also spill out some diesel.

5. Remove the pin on the back of the fuel filter. I wedge a screwdriver between the pin and filter and it slid right off. This part was nice and easy, you may be able to pull the pin off with your fingers.

6. Here is where I say don't hack up your car. There is a circular object(fuel heater) that has 2 things running into it. A fuel line and an electrical connector. Both of those things STAY ATTACHED. All you have to do is pull that round thing away from the fuel filter, and they should separate fairly easy. Try twisting the fuel filter while pulling the 2 things apart in order to get them separated. Diesel will drain out of the fuel heater.

7. There is a small Torx bolt that tensions the bracket onto the fuel filter. Remove the bolt, and slide the metal bracket and rubber sleeve off of the old filter.

8. Put the rubber sleeve on the new filter in the same location that it was on the old filter. This ensures everything lines up when you put it all back together. Tighten up the bracket onto that rubber sleeve. MAke sure you put it on the right way. You can also pre-fill the new filter with diesel if you so desire. I didn't.

9. Slip the front of the fuel filter into the front fuel line, and tighten the clamp up around it.

10. Slide the fuel heater assembly onto the back of the new filter.

11. Put the pin back on the back of the fuel filter,

12. Give everything a tug to make sure it's all connected tightly.

13. Reattach the fuel filter bracket and the electronics box back to the vehicle.

14. Put the underbody panel back on.

15. PRIME THE FUEL SYSTEM. You need to get the air out of the fueling system or your HPFP is going to have a rough time. There's a few ways to do this. Either get the Schwaben scan tool and cycle the 60l/hr pump a few times until you stop hearing air. You can also directly wire the low pressure fuel pump an run it until you stop hearing air.

16. Fire up the car and if everything works well, pat yourself on the back. Job well done!

Differential Fluid

Here is the guide I used for changing the differential fluid. This is much more straightforward than the fuel filter.
This is the suction gun that I used instead of using a transfer pump. This worked shockingly well.

Here's my abridged step-by-step guide.

1. Lift the car. Make sure it is level. Put a drain pan under the differential.

2. Pop off the differential drain/fill plug.

3. Get your transfer pump or whatever you have, slide it into the drain hole, and try and get it to touch the bottom of the differential. I put a piece of wire inside the hose in order to be able to bend it. You just want to be able to get as much old fluid as possible.

4. Pump that old nasty stuff out. Mine was really dark in color and smelled awful. The smell reminded me of DSG fluid from Volkswagen. I can't stand the smell, it makes me sick to my stomach. I don't know whether or not the new stuff smells as bad, my senses were messed up already after draining out the old fluid, as well as the diesel fumes.

5. Pump in new fluid. I used Genuine BMW fluid because it wasn't much more expensive than anything else. I pumped in 1.5 liters, and had some come flowing back out.

6. Allow the fluid to drain until it stops dripping, and then put the plug back in and tighten it to 44 ft-lbs.




Hopefully this is helpful to everyone. If you have questions, let me know. I'm happy to help!

[Persian Whisperjet]

Great writeup!

I had bought one of those plastic fuel line clamp tools to seal off the line to the engine but when I did the change I was surprised that a) the line was quite rigid and a plastic clamp tool was not going to do anything and b) very little fuel trickled back down from the engine.

[Torqu3]

Originally Posted by Persian Whisperjet

Great writeup!

I had bought one of those plastic fuel line clamp tools to seal off the line to the engine but when I did the change I was surprised that a) the line was quite rigid and a plastic clamp tool was not going to do anything and b) very little fuel trickled back down from the engine.

I was going to shove a golf tee into the front fuel line, but by the time I was under the car pulling stuff apart I had forgotten the tee. So I just pulled the lines and very little fuel came out of either end.

Of course, if you're going to try and do the fuel filter without purging the system afterwards, you'll need to block the lines and pre-fill the filter in order to minimize wear on the HPFP.

[BB_cuda]

Some of us are of the belief that a purge of the FF before reconnecting the front line (which leads to engine). Personally, I ran an extra hose from the FF outlet to the pan and pumped (by directly powering pump with battery) about a liter through into pan. This was to ensure no contaminant was introduced from new filter and/or breaking into system. Credit to TDI for the idea. This in no way replaces the system purge of air after front line is reconnected.

This is why I don't mess with filling the filter with diesel as I do it with the pump.

[Torqu3]

Originally Posted by BB_cuda

Some of us are of the belief that a purge of the FF before reconnecting the front line (which leads to engine). Personally, I ran an extra hose from the FF outlet to the pan and pumped (by directly powering pump with battery) about a liter through into pan. This was to ensure no contaminant was introduced from new filter and/or breaking into system.

That's a really good idea! I wish I had thought of it when I was replacing mine. However, everything was clean, and is running nice and smooth. Plus my car seems to be running quieter and not shaking as much. It's probably just a placebo effect, but I'll take it.

[Thecastle]

Originally Posted by Torqu3

That's a really good idea! I wish I had thought of it when I was replacing mine. However, everything was clean, and is running nice and smooth. Plus my car seems to be running quieter and not shaking as much. It's probably just a placebo effect, but I'll take it.

Diff fluid always smells real bad. I've done it 4x on 2 vehicles, it has a strong sulfur+ass smell.

I also added MOS2 to mine, what fluid did you run?

[BB_cuda]

Originally Posted by Thecastle

Diff fluid always smells real bad. I've done it 4x on 2 vehicles, it has a strong sulfur+ass smell.

I also added MOS2 to mine, what fluid did you run?

Parts of Pasadena smell like gear oil too.

[Torqu3]

Originally Posted by Thecastle

Diff fluid always smells real bad. I've done it 4x on 2 vehicles, it has a strong sulfur+ass smell.

I also added MOS2 to mine, what fluid did you run?

This is my 3rd time handling this smell. The first 2 times were DSG services. I almost puked walking into my shop/barn earlier because it still smelled bad 24 hours later.

I just run the genuine BMW stuff. It was about $35 for 2 liters. Barely more expensive than the other options I found, so no worries.

[Yozh]

Torqu3, you may wish to link this thread in the DFFF one so info stays in relevant places.

[Persian Whisperjet]

Originally Posted by Torqu3

I pumped in 1.5 liters, and had some come flowing back out.

OK that is very interesting I only managed one liter. I guess there was old fluid left inside. I rigged up a sort of elbow thing but the wire idea is intriguing.

[BB_cuda]

I only pulled out one liter and this was a diff that was out of car. I leaned it up to get as much possible sucked out. The driveline shop says there was only perhaps another ounce in it still when they took off the cover. One ounce equates to 30 mL or .030 L.

[Torqu3]

There's a very high chance that I only actually filled in 1 liter. I pumped in 1 liter and had nothing flow back out, and then pumped in another half liter, and as soon as i pulled the tube out I had a pretty good amount of fluid flow back out. I didn't measure how much came out or went in. Just filled it up with 1.5L and let whatever was too much come flowing out.

[BB_cuda]

I bought 3 L of diff fluid for a first 1000-1200 miles break in and then follow on fresh change of fluid per instructions. It sounds like I will have some left over. Can't wait to get the Wavetrac underneath the beast. I'm using Motul Gear 300 75W90 gearcoil. It has no friction modifiers added. It's important to have no modifiers with a gear type LSD.

[Torqu3]

Keep us posted on the Wavetrac! That'll be the last performance mod I do to my car, so it is a long way down the road, but I'd still love to hear what it's like. Just curious, but are you going to DIY the install, or have a shop do it?

[BB_cuda]

Originally Posted by Torqu3

Keep us posted on the Wavetrac! That'll be the last performance mod I do to my car, so it is a long way down the road, but I'd still love to hear what it's like. Just curious, but are you going to DIY the install, or have a shop do it?

Planning to DIY. Have had trans jack and special 50 mm thin wrench on loan from friends. Many examples of process to change out on bimmerfest, some on e90post, as well as the net. There is an absolutely wonderful thread here in our sub forum written by Techevo. He did all of his own machine work to convert over to Wavetrac.

http://www.e90post.com/forums/showthread.php?t=1064264

[335dlci]

Originally Posted by BB_cuda

Planning to DIY. Have had trans jack and special 50 mm thin wrench on loan from friends. Many examples of process to change out on bimmerfest, some on e90post, as well as the net. There is an absolutely wonderful thread here in our sub forum written by Techevo. He did all of his own machine work to convert over to Wavetrac.

http://www.e90post.com/forums/showthread.php?t=1064264

Do you have plans for the dsc nazis aka coding?

[sergio 61]

Originally Posted by BB_cuda

Some of us are of the belief that a purge of the FF before reconnecting the front line (which leads to engine). Personally, I ran an extra hose from the FF outlet to the pan and pumped (by directly powering pump with battery) about a liter through into pan. This was to ensure no contaminant was introduced from new filter and/or breaking into system. Credit to TDI for the idea. This in no way replaces the system purge of air after front line is reconnected.

This is why I don't mess with filling the filter with diesel as I do it with the pump.

Is there a guide or something showing how to connect directly to the pump and activate it? I also would need to get the fuel out of my tank as I think I put some bad diesel inside. Maybe I can get the old fuel filter out, pump the bad fuel out and then put new filter? The car started acting up, starting and running horribly, also got fuel pressure too low code.

[Nadir Point]

Originally Posted by sergio 61

...as I think I put some bad diesel inside.

Contaminated fuel system can be a very problematic issue on a commonrail diesel. Cap that fuel line and don't connect another filter or anything else until you get the tank properly flushed. It doesn't take much in the way of dirt and water to ruin the HPFP and injectors.

[sergio 61]

Originally Posted by Nadir Point

Contaminated fuel system can be a very problematic issue on a commonrail diesel. Cap that fuel line and don't connect another filter or anything else until you get the tank properly flushed. It doesn't take much in the way of dirt and water to ruin the HPFP and injectors.

I emptied the whole tank and changed the fuel filter. Did fuel bleeding as well. However, I keep getting reduced power engine malfunction light and low fuel pressure code. I had a zero-quantity adaptation cylinder 4 with smooth running controller code, but that was even before the bad fuel problem and the car was running great. What should I do now? Reset the adaptations maybe? As maybe the car got used to trying to run with diesel with water? have no clue

[Nadir Point]

No, they don't run at all on anything but pure hydrocarbons. That's one reason why the filter is rated at 4um.

[sergio 61]

Originally Posted by Nadir Point

No, they don't run at all on anything but pure hydrocarbons. That's one reason why the filter is rated at 4um.

Well I added a bottle of heet when this happened (before emptying the tank) and after a lot a lot of cranking it started and I used the car a few days even if it ran bad