On the 9th day of Christmas my e39 got it's mojo back thanks to new O2/MAF Sensors!

On the ninth day of Christmas my

"e39 2000 Biarritz Blue 540iA with Sports Package" gave to me...

..new Oxygen sensors and a new Mass Air Flow Sensor!

I decided to document my adventures to replace my daily driver with a 2000 e39 BMW 540iA Sport. It is long and you can't get your time or money back so read on at your own risk. I am cross posting to my favorite forums so I apologize if you are like me and you frequent them all. Smoke em if you got em...

Here is a review of everything to date!

First day of Christmas I purchased a e39 540i as a run around daily driver that would be a lot more fun then the land barge I was driving. (10/3/2006) - 2000 e39 540iA Sport with 79,000 miles ($14,000) - 1 hour technical inspection + drive ($100) - Coolant system Cost = $14,100 Running Total = $100 (maintenance)	On the Second day" of Christmas I drove it down to an indy I thought I could trust and ended up giving back all the hard earned money I bargained out of the car. (11/1/2006) - State inspection - Wiper Blades - Oil Filter / Oil - Oil filter mounting bushings - 2 Power steering hoses near reservoir - Valve cover gasket - NKG spark plugs and tune up - Front brake pads and rotors - 4 wheel alignment - 2 serpentine belts - Lower Oil Pan Gasket - Thrust arm bushings - Front wheel bearings - 4 new Falken Zien tires - Ambient temperature sensor and wire Cost = $3,400 Running Total = $3,500	On the third day of Christmas I did my first mods and had the paint professionally touched up from front to back (11/5/2006) - TEC BMW E39 5 Series Cup Holder ($500) - Homelink transmitter - M5 Spoiler (unpainted) - Pieke diagnostic tool - Bentley Manual Set 12/1/2006 (total of $300) - Paint touch up - Front bumper repair - Rear M5 wing paint and installation Cost = $800 Running Total = $4,300
On the forth day of Christmas I emptied out my bank account with Matt and www.Umnitza.com (12/10/2006) - Predator Angel Eyes with 6k HID kit and Euro clear corners - Remote Angel Eyes activation - Rear cup holder replacement (OEM) - White fog light bulbs - Clear side markers with white bulbs - Lumin-X protection for lights - BMW Driver's side OEM cup holder Cost = $1,000 Running Total = $5,300	On the fifth day of Christmas I tried my hand at body work, put on new license plate holders, and purchased an //M sport OEM replica lower lip spoiler. (12/14/2006) - 2 new WeatherTech license plate frames - //M sport lower lip spoiler replica - Prep, paint, and installation Cost = $200 Running Total = $5,500	On the 6th day of Christmas my e39 gave to me 1000 MP3s with a new MP3 Changer! (12/17/2006) 1) Alpine CHA-S634 6 Disc CD MP3 Changer ($235 shipped) 2) Alpine KCA-130B Ai-Net/M-Bus adapter ($25 shipped) 3) Soundgate v5 or higher BMW/Alpine M-Bus adapter 4) Ai-Net male to male cable ($30 shipped) 5) Duralast AutoZone Battery Cost = $500 Running Total = $6,000
On the 7th day of Christmas my e39 gave to me - new rear brakes & new air filters! (12/18/2006) - Rear Brake Disc from Brembo (OEM) for $54.61 each (x2) - Brake Pad Set from Pagid (OEM) for $51.87 - Brake Pad Sensor for $16.83 (I didn't need it as my sensor never went off) - Interior Cabin Air Microfilter $35 each (x2) - Air Filter $17 Cost = $250 Running Total = $6,250	On the 8th day of Christmas my e39 shifted like new thanks to a DIY full transmission and differential service (12/19/2006) - RLDFL Red Line Synthetic Differential Fluid - 2 Quart 2000 540i = $17.90 - 24 11 1 673 KIT Automatic Transmission Filter Kit 2000 540i = $53.95 - 02341 Tool - Oil Filter Housing Cap - 36mm socket (with 17mm hex head) 2000 540i = $17.95 - 11 42 1 745 390 Oil Filter - Plastic ends - With Seal Rings 2000 540i (3) = $29.85 - ESSO LT71141 Automatic Transmission Fluid - 1 Liter 2000 540i $18.95 (6) = $113.70 - 61 66 1 379 054 Washer Bottle Cap 2000 540i $1.95 1 = $1.95 - ATE GOLD Ate Super Gold Racing Brake Fluid - 1 liter = $12 Cost = $260 Running Total = $6,510

The next thing that was bothering me was the power. Not enough of it and not enough of what I hoped and prayed a 540i should be. Even with the slush box transmission I should be laying down posy in first and probably second. No dice.

Well I did some research on these boards and a lot of people replace the pre and post catalytic converter O2 sensors and MAF sensor around 80,000 miles. I figure - why not and start searching for parts. WHHAAATTT! This is an O2 sensor and air sensor - not a device that turns lead to gold. Once again - www.BavAuto.com had great service and the best prices on the net for the o2 sensors and the magic tool (for a whapping $390 total!). I know you can buy AutoZone and PepBoys replacements but I wanted good German parts at this point:

- OSW1 Bosch Oxygen Sensor Tool 2000 540i $18.95 (x1) = $18.95
- 13 475 Oxygen Sensor - located after catalytic converter - 2 required per car 2000 540i $109.95 (x2) = $219.90
- 13 802 Oxygen Sensor - located before catalytic converter - 2000 540i $74.95 (x2) = $149.90

As for the MAF Sensor - NO WAY. Sit down for this one. new BOSCH air mass sensor dealer list price = $393.00 (Part number: 0 280 217 800)!!!!! Are they crazy!?!? I can't believe I am looking at almost $800 in parts. I feel for all you M5 guys as there are 2 of these in your cars!

Time to break out the handy dandy search engine again! I saw on some of the M5 boards that guys were swearing by replacing the BMW MAF with the BOSCH sensor inside of Volkswagen.

I found the following on http://www.performance-cafe.com/

1 x OEM VW MAF MK4 cars all (part #06A906461A) = $79.00
------------------------------------------------------
Sub-Total: $79.00
United Parcel Service (1 x 4lbs) (Ground): $11.71
Total: $90.71

Well - still not inexpensive but a lot cheaper then the BMW option. The only problem is you have to remove the housing it comes with and swap the sensors. There was also a lot of debate on if this is the exact same unit. To save $300 bucks I aim to find out for myself!

100_4009.jpg	Well here they are. Careful - careful handling them! I lift and move these around like Indiana Jones in the Temple of Doom handling priceless antiquities! While they look like German Bosch OEM O2 sensors they are thinly disguised $100 bills. Thank goodness the car needs 4 of them to run
100_4011.jpg	Well here is the fancy $19 helper tool. It has one end that you can insert your 1/2 drive socket into and the other end is cut out to go over a standard 22mm O2 sensor. The cut out is so you can slip the wire through it. Pretty cool I guess.
100_4012.jpg	Well I figured might as well start with the 2 post catalytic converter O2 sensors as they are easily accessible under the lift. I slip the tool over the wire and loosen easily enough. I guess for $100 each they should remove themselves and fix me a Manhattan!
100_4013.jpg	Turn and turn until it is out. I had to remove the wires from the cable management to twist them enough times to remove them.
100_4014.jpg	Unfortunately - I don't know which is which inside the boxes so I decide to take them out. It "appears" the only difference between the two types of O2 sensors is the length of the pigtail. That extra foot of cable costs $25 each! Damn!!!
100_4015.jpg	Well when you follow the cable you will find the mounting box. It looks like their should be 2 O2 sensors going through there? Why? Is this part sharing with the 6 cylinder cars? Anyway - this is really easy. Just remove the nuts holding on the plastic cover and remove it and the cable management to get to the plug
100_4017.jpg	Mine where pretty glued together but with enough force I was able to unplug the O2 sensor.
100_4018.jpg	Well over to the workbench to see if there is a difference. I will be damned. Look at the difference from old (left) to new (right). Incredible. Can this be a cause of my power problem?
100_4019.jpg	Here is a close-up. One nice thing is they have some locktight type grease on the threads when you remove the cap. VERY IMPORTANT. When you handle an O2 sensor it is critical you don't get anything on it (especially WD40 or anything else). If you fowl one of these up you are out $100! I wouldn't touch them to anything if I were you. When I put them back in I made extra sure I didn't even touch the sides of the exhaust tubing. These went back in without any fuss!
100_4020.jpg	Here is the front one. Oh oh. These don't have any room to work around and I can't get my $18 tool + my torque wrench in there to remove or insert them. I try a bunch of things and nothing works. Well years ago I moved the O2 sensors on my NSX from the old headers to the new headers I purchased. Do you think the old school box wrench will fit? Will it work? Absolutely! It is tight but you can definitely use the open ended side to break it loose.
100_4021.jpg	I went ahead this time and removed the cable management
100_4022.jpg	and unplugged it first so you can turn it.
100_4023.jpg	As you can see - there is really no room to work in there with the special tool
100_4024.jpg	But my old standby 22mm socket wrench did the trick! Well - once again it is time to see what $400 in Oxygen sensors does for my 80,000 mile BMW 540i. I head out to some open roads. Ohhh - mmyyyyyy - Goooooood!!!! Scary difference. Not just a seat of the pants little bit better - it is 6lb roots supercharger better. With the transmission fluid the cars now brakes loose the tires in first and second gear without even full throttle! HUGE difference. If your O2 sensors look like mine - go for a spirited drive with a buddy before and after. Have him go inside your place and in an hour have him come back out and go again for a drive. He will be begging to know & show what type of forced induction you put on. If you really want to play with his mind put one of those tornado boxes in the trash can and have him think and post that you got a huge boost from that POS! Too funny.
100_4081.jpg	True story - right when I get back UPS shows up. They are so busy this time of year they drive around in Budget Rental trucks!
100_4082.jpg	Look what we have here! I bet I know what this is! It is the exact same (I hope) Bosch MAF sensor with a different housing for $300 less then the dealer. This is living proof that the same parts are JACKED UP in $$$ just because by buying a BMW they think you are elmer j fudd with a mansion and a yacht!
100_4083.jpg	Here is the Volkswagen housing with the sensor. Now to find the equivalent one on the 540!
100_4084.jpg	Well - we know how to do the air filter so it can't be too hard. Pop the clips and hit the clamp with your screwdriver. Pull out the plug on the top and you are on your way to pulling this baby out. Easy!
100_4085.jpg	Now the hard part. Apparently they really like screwing us BMW owners so they keyed the screws on this POS. How evil are these people!!!??? Why would they do that? I tried to use various things and tools and eventually have to resort to a really good pair of channel locks with a fine grip. You basically lock onto one and keeping it very steady start to remove these bad boys. Warning - you will gum up the screws a little but if you are careful - not too bad. You will see.
100_4086.jpg	Well the new one is out (just pulls out). Will it look the same as the old one?
100_4087.jpg	Here is the old one with the same sensor removed. They look EXACTLY the same.
100_4088.jpg	Here is a close-up - twins separated from birth. All the colors on the resisters, everything appears exactly the same. Others have tested them and they are identical in operation too! Back for a test drive. This time I really didn't notice any difference. I think my stock ones with the paper filter were working perfectly fine and needed no replacement at this time. I figured with the O2 sensors being replaced and the amount invested coupled with the age and miles on the car it was a good time to bite the bullet. YMMV! Still very happy with the performance improvement! Now this thing can really rock and roll!
100_4093.jpg	Oh - my wiper fluid cap had cracked and given up so for only $2 I purchased an OEM replacement. Finally a DIY fix that you can afford and ANYONE can do without screwing up. Total time 15 seconds! Next up? Time to get that sweet running engine to start singing and looking good!