BoostedAero

If you do not currently log, "how do I put this gently", It is not the smartest thing and you should.

So I am a big fan of knowing before and planning for if and I would rather have it and not need it than the other way around....

I just did fuel pumps, senders and new tank less than 10k miles ago under warranty

My fuel pressure should be great right? Well think again


It was real intermittent and would come and go

Some runs in the 12.x range

Most would stay in the 11.x tolerable range as they should

I tested fuel pressure, under heavy load it dropped to about 45-50PSI when it should be around 60PSI.

And look at what I discovered with the new pumps



This led me back to MB as parts installed have a 1 year unlimited mileage warranty (it was less than a year )


So the work was done and now she is happy for now (minus a high IAT situation I created with a 185mm CP)

Hope this helps some become more aware, or maybe stimulate you all to have a want to become more aware of your motors health. We maintain sedans that are really race cars =D

Max.H

What are you using to log? I asked this same question about this before. But, all was quite.

Ive always worried that with dirty filters and excessive amp draw on from your pumps can cause a lean situation.

Thanks for sharing!

SICAMG

I have always run digital wide bands for left and right and also fuel pressure and IAT. Must have's with any car and answers a lot of questions if you have some sort of issue.

bbirdwell

One other item to consider.

Check that your harness power/ground match the fuel pump power/ground. With the latest part number below one of the pumps has a reversed power/ground compared to the older pumps. 12 amps (forward) on one pump and 3 amps (reversed) on the other pump is the clue.

If using the latest fuel pumps, 211-470-00-00 Fuel Sending Unit (dual pumps), you must use the adapter harness 211-540-07-00 (adapter cable to fuel pumps). The adapter cable reverses two of the leads.

See photos; pins 1 and 2 are swapped using the adapter to match the new fuel pumps. My home-brewed test device displaying 3/13 amps indicates one pump reversed power. 13/13 amps indicates proper connection.

You can swap the stock harness pins but a fuel pump replacement in the future may result in the next owner inadvertently ending up with the same "swapped pin" situation.

I agree wide bands and fuel pressure logging is the way to go.

BoostedAero

Gotta love it when we need to check the dealer's work for a faulty installation!

BoostedAero

I thought dirty filter too! I run Techron fuel cleaner every 2-3k miles and all that got changed with the refresh... so I was kinda stumped

Barry (Bbirdwell) hit the nail on the head though. The dealer had a mis-install of parts. Sad day when we have to look over the dealers work

See post #2 for more info

https://mbworld.org/forums/w211-amg/...atalogger.html

Basically Zt-2 and PC with Android/Torque Pro

Hulk

This is not a surprise
Dealers usually have the rookies do the tank replacements
The foreman is not doing their work

MACEDON

Wait you have to routinely replace your gas tank???

Hulk

The filter in the pump and senders do need to be changed as maintenance but because you can't buy just the filters you would need to change the whole assemblies

MACEDON

Grrr why did they do away with the inline filters, my w208 is so easy to maintain

So I gotta add that to the list when I take it to the shop next week, to get that **** checked out, I'm unfamiliar... is this a diy friendly job?

Hulk

Pretty straight forward
I agree dumb design!

Simmelma

So i'm gonna noob it up here , I haven't messed with the fuel system on the W211 yet, but I've had the tank recall performed, where are these wiring harnesses located so I can check them? I'm assuming under the rear seat?
TIA!

BoostedAero

Under rear seat- passenger side, check for over current on pins of fuel pump hat or build an awesome set up like Bbirdwell has for testing as seen in the pic...if you just click on his name and find posts by him search for all his fuel tank info. Its pretty much gospel and you need to read it if you own this car

Thanks Barry for your hard work compiling and documenting an achilles heel of this chassis!!!