BLKROKT

That's so weird Ryan. I've got to think that you're right that one of the fuel pumps is struggling for some reason. How to test it is the question. If they're cheap, it might just be good to replace both?

Jasonoff

Maybe one or both pumps are getting to hot so with less fuel it's not enough to keep them cool?

Alex.currie44

Yup!

Ryan951s

I'm running NA airboxes with the charcoal filters removed and K&Ns. I think stock filters might be the next step as I've read a couple posts about K&Ns causing these symptoms. Why it would only be on right handers once the fuel drops is a bit beyond me, but I think stock filters will be the next step to try.

it seems like a fuel delivery issue, but I just can't see how it would happen at half a tank of gas. I think we're just dealing with something really weird and we'll need to track it down piece by piece.

Since filters are cheap and easy, I'll start there and cross that one off the list. If it persists then I'll focus more directly at fuel delivery.

Thanks for the info gents, appreciate it!

Ryan

ps. The car was a lot of fun again at the track. Definitely need some tires for next season (I'm running Conti Extreme Contacts as this is my first year at the track with the car), but the upgrade to Motul 600 RBF and Powerstop Track Day pads certainly woke up the braking. I've now joined the 'bronze caliper' club. (I'll post a review of the pads in a separate post.)

Alex.currie44

You know, while I have had 11 MB cars in my lifetime I, like you, are relatively new to this beast but if life with MB cars has taught me one thing it is that I can choose to struggle to figure some stuff out or take it to my ever reliable tech at my dealer and let him sort it out. Usually it takes minimal time and less stress than trying to do it myself and can in the end be less costly. You have more going on here that air boxes, MAF issues etc. The fact that it is one sided and specific makes it more complex.
Save you self the angst and take it to someone who can tell you what it is and how to fix it.

BLKROKT

So, just to add here. I was looking for something else on OEDiscountParts, and their system shows that the FL/BS models ALSO have 2 fuel pumps. Just thought this was interesting. They're only like $300ea so probably worth replacing on higher mileage cars.

Alex.currie44

Very interesting as the info I found said that the 2010s onward were single pump but then again Pelican Parts is saying 2 per vehicle in 2011, 2012 and 2013 so I guess there are 2 and the earlier info I dug out was not right. Good one guy!

Ryan951s

BLKROKT

ItalianJoe1

Saddle tank, one side has to transfer to the other, if there is a transfer issue it could start to run low once it goes down to half.