Good to know. Gives an option for those with mechanical ability not wanting to buy the $2400 PZEV replacement tank.
The pump you listed Mercedes-Benz (211-470-21-94) is not the pump that fits. I will try and find the match. It is the pump for a 2007 S550 that matches, EDIT: some sites show the proper pump fits the 2010 S550 so don't limit search to the 2007 model year, not sure what other models it also fits but the S550 pump is inside the 2007 E350 PZEV sealed tanks. Mercedes-Benz (221-470-84-94) looks like the correct part.
Edit for correction 4-30-22, I ended up ordering a Delphi Fuel Pump CFE0727, fits a 2008 Mercedes S550 plus many other models, the picture showed a good match and it is a $289 part locally. My pump installed a few months back had started to growl a little, it also was not holding pressure when engine was shut off which bothered me. The car started and drove perfectly but I lost trust so I just popped my new cover and installed a new pump.
The Delphi FE0727 pump was identical but the module that holds the pump was just a touch off. The hold down locks could not be used, the pump needed to rotate a little. I could have modified it to work but I realized my old pump module body was perfect, it just needed the new pump and filter so I used the new parts from the Delphi module. In about 5 minutes I swapped the pump from the new body module ( the plastic container that holds the pump) to my old body module and the pump lined up perfect on install. The Pump power wire and ground wire hook up a little differently, my old pump was soldered on the new pump had two male spade connectors on the pump, so I crimped female wire spades on my wires and hooked up the new pump. Now it holds pressure on shut off, only lost 5 lbs pressure in 30 minutes after shut off, that is good, with the Carter pump it never held pressure after shut off. The car seems to run even better. I take the blame on the first pump failure, figuring out the PZEV conversion I am sure I got some debrie into that pump which killed it, pumps only run on clean fuel, any dirt damages the fuel lubricated motors. I washed out the tank before the install but it was apart and together a few times as I worked things out. The Delphi pump was a much better fit than the Carter pump I used first and it has really good reviews at several places.
Edit, I should have noted, the new cover I installed on the passenger side to allow access to the new fuel pump is an 8” cover, the access hole below the rear seat is only 7”. To change the pump with this large cover in place I had to remove the nut that bolts the tank to the inside passenger compartment. A 13mm nut is dead center under the pass seat on the driveshaft tunnel. Remove this, now go under the car and remove all 4 bolts on the gas tank straps. The tank will sag about 2” down but your driveline and exhaust are there so it can’t fall out. This extra 2” allowed me to slip the new pump cover over the top of the tank where I left it while I installed the new pump. On install I just reversed the procedure. Once the cover was on again and tight I went under the car. Pressed the tank up and started the strap bolts. Then I went inside and installed the 13mm tank bolt which is under the rear seat. Now I went under again and tightened the 4 tank strap bolts. I forgot to mention, to access the strap bolts you do have to remove two heat shields, they have 6 bolts each side that are plastic 10mm zip nuts. Sounds like work but the whole lower the tank process did not take 15 minutes. Much easier than dropping the entire rear suspension and the exhaust to access the fuel tank. Just a follow up FYI. The car really does run perfectly, I am very happy with the results and I am pretty picky. Fuel Pressure is a very steady 58 PSI and holds after shut off And it is quiet.
