bfnnrgn

I've noticed something strange in the past few days with my E55. Usually on my to and from work I average about 14 mpg, with an overall lifetime average at 13.6mpg But over the last couple of days it has been at 17 to and from work. The route I drive or my driving habits have not changed in the last few days. The only thing really different has been a few long highway trips over the weekend at cruising speeds about 60-65 and I was using cruise control.
I was concerned with a loss of power, all this extra gas mileage has to come at some cost. So for lunch today I went out looking for a kill or two. I happened upon a red mustang gt(new body) and that was the best I could find willing to race. I was able to beat him, but only barely. No idea if his car was stock or not, he made an abrupt U turn after the 2nd go or I would have asked. We were however neck and neck for a while before I slowly pulled ahead and he even gained on me at first when we started at about 40mph. I know last weekend my car was running great, when I would floor it at a stop I could feel the blood rush out of my head and vision start to blur. But now it feels kinda blah. Was going to run it over to the shop but thought I would see what the real experts thought first.

SamE55

Take it to the dealer and have them check the intercooler pump

Vadim-SoCal

Presicely! Do a search under "intercooler pump"

Your mileage is better because kompressor gets turned off by high air charge temperature due to intercooler pump failure.

bfnnrgn

Well I took it to the dealership, Ewing Autohaus, and they said there's nothing wrong with it, no codes etc. I asked if they drove it, they said yes for 5 miles on the 40mph street outside the dealership. They said it felt fine, but they don't drive my car all the time, I do and I know theres something off with it. I asked why I would suddenly get an extra 4 mpg that wasn't there before and all I got was as you put miles on it it'll get better mileage. Fair enough, but 4 extra overnight?

I asked them if they'd put it on a dynojet and they said no. What else could they look at on this thing?

KenE55

This discussion begs the question; can one intentionally disable the supercharger? I would love to have a switch that would disable the SC to improve the gas mileage when I didn't want the extra power. I've only had my 2006 E55 for a few days, but I already know one thing I'm going to miss about my 2002 E55 is the mileage. I would consistently get about 22 MPG on the highway in 2002, around 16 around town if I behaved myself.

Has anyone installed a SC disable switch you could turn on and off while driving? Is it possible?

bfnnrgn

Is it possible that my onboard computer is defective? The car is still running very poorly and when I dropped it off at the dealership the computer was reading 18mpg. I'm sorry, but theres no way an E55 can get that kind of mileage in city driving, my CLS500 or E500 could only get 15.5 on the same route. If the onboard computer were off could that affect the engine performance in some way?

Evolution Marine

bfnnrgn - Try another dealer, one that is more into the AMG models and has some good Techs. - Bob

Fikse

is there a way to measure boost pressue? if so, that would tell you right away if something is wrong...