Lately on my CL55, after a couple of hard pulls on the highway, the car stops pulling hard. The car still holds the gear but when I floor it, it feels like its missing half the HP and sounds totally different. It accelerates very slowly, like a 250hp car. There is no check engine light or anything.

Any ideas??

 

maybe your SC belt is slipping therein causing the SC to be ineffective.

 

youre intercooler pump is bad which makes your IAT's skyrocket, once IAT's go over 190 the ECU engages the supercharger clutch, what you are experiencing is your supercharger literally shutting off after hard runs.

 

As Driven points out, it's the charge air cooler (aka intercooler pump).
You won't get a CEL and it won't throw a code so if you go to a dealer who tells you, "there's no code showing", tell him ... well, just tell him he's right.

If you can do some datalogging it's really easy to show in an excel spreadsheet exactly when the s/c shuts down. That's what I did with my SA.

Of course you can always take them for a drive until you force the event to happen.

It happens to most 55's, almost all E55's and fewer of the CL's, SL's and S class because they have a different cooling system than the E class.

Probably a $300 fix with parts and labor.

 

Thanks for the informative responses. I brought it in the dealer about 2 times for this problem and they couldn't figure it out. They said they could not replicate it, but I am just guessing they are not driving the car hard.

The temperature does get pretty high and the car is getting horrible gas mileage. I will tell the dealer its the intercooler pump, hopefully they will be able to replicate the problem.

 

Youre going to need more than just an OEM pump. Youre going to need the Johnson CM30.

 

+1 for the Johnson CM30 many have been praising it lately.

 

LOL, I would put the Johnson pump on, but my car is still covered under warranty and I don't beat it that hard. Just the occasional run in with some R-rockets.

 

the problem is that the factory pump is very inconsistent and prone to multiple failures. The johnson pump is just more consistent as I have yet to hear of any failures, as well its less money then a factory pump at about 125.00 its an easy piece that you can put in and forget about unlike the factory pump. I run a Johnson pump in my Cl600.

 

When I took the SL55 into the dealer to get the pump fixed, I just told them "my supercharger shuts off after like 2 runs at 100mph+. I have a couple of friends who have V8 Kompressors and they all had the same issue and that it was their IC pump that was the issue." The SA said no problem and just replaced it for me with no questions asked.

I'm sure they'll do it for you if you specifically ask.

Good luck!

 

Sounds like the exact same problem I am having. I am dropping the car off tomorrow. Hope all goes well.

 

that famous I/C pump failure is probably the only thing that has went bad in AMG engines ever.. correct me guys if i'm wrong but AMGs are bulletproof

 

i had the pump replaced OEM on both my E55 and SL55 and after that the problems were gone and the car felt more alive just about all the time

my tech explained to me that the pump kept being updated from 03 to now and the pump of today features many design upgrades so that is shouldn't fail the way the old one did

if thats right... i dunno - but the cars ran perfect and rock solid until i traded both of em in a few weeks ago