Cant accelerate over 4500 rpm in kickdown

SL Boy · 08-07-2005, 06:24 AM

I have recently bought a used SLK32 which I like immensely but it has one annoying fault - at least I assume its a fault. I floor the accelerator into kickdown mode and there is a huge surge of acceleration as you would expect but only up to about 4500 rpm at which point the car refuses to go up to the red line or change up to the next gear.

The "juddering" effect is similar to that when reaching the 155 mph rev limiter in top gear.

Is this normal or is it actually hitting the rev limiter which perhaps is adjusted too low or does it indicate a more serious fault.

all help welcome....

thanks

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vraa · 08-07-2005, 06:34 AM

I think it's due to some kinda improper coding.
I'd ask the dealer to reflash the ECU.

MidniteBluBenz · 08-11-2005, 05:40 PM

Thats definetly not normal. I'd take that to the dealership and get it checked.

What octane fuel do you put in it?

SL Boy · 08-12-2005, 11:12 AM

Thanks for your replies.

I use 95 Octane fuel. Used to have a 230K SLK and used the same fuel with no problems.

Trekman · 08-12-2005, 11:19 AM

sound like your supercharger has gone bad.... have the dealer look at it

Jon Winter · 08-18-2005, 10:58 AM

Throttle actuator or Temp sensor

Jon Winter · 08-18-2005, 11:01 AM

I'm sorry look at the innercooler pump also. Does the car runs fine until you step on the gass hard?

SL Boy · 08-19-2005, 05:14 AM

Yes Jon, runs fine under all other conditions. Will get it checked.

SL Boy · 06-16-2006, 04:39 PM

Well it has taken me all this time to sort the problem as it didnt happen at all when the outside air temperature dropped below about 25 deg C which of course it did in the UK at the end of August.

With June temperatures above 25 deg again, problem returned but has now been cured.

There is a water cooling jacket around the supercharger and an auxiliary water pump to redirect the cooling system water through this jacket at air temperatures greater than about 25 deg. The pump had started to fail and blown its in-line fuse. As a precautionary measure when the uncooled supercharger reached a certain temperature the ignition was automatically retarding to stop any damage occuring.

So new pump and fuse fitted - problem solved.

Nice to know that Mercedes/AMG engineering introduced a failsafe process here to stop major damage and expense.

08-07-2005, 06:34 AM	#2
vraa Administrator Join Date: Jul 2002 Location: Texas Posts: 28,803 Drives: M6 Coupe	I think it's due to some kinda improper coding. I'd ask the dealer to reflash the ECU. __________________ 08 IS-F \| 04 360 Modena \| 07 LX470 \| 08 LS600 \| 07 M6

08-11-2005, 05:40 PM	#3
MidniteBluBenz Super Member Join Date: Mar 2003 Location: Toronto, Canada Posts: 554 Drives: 540i, 300E	Thats definetly not normal. I'd take that to the dealership and get it checked. What octane fuel do you put in it? __________________ Prash

08-12-2005, 11:12 AM	#4
SL Boy Senior Member Join Date: Aug 2002 Location: UK Posts: 303	Thanks for your replies. I use 95 Octane fuel. Used to have a 230K SLK and used the same fuel with no problems. __________________ Paul 2003 SL55 - Jasper blue/alpaca 2003 Smart Roadster Brabus - blue/black 2002 SLK32 AMG - lazulite blue/black 2001 E 320 CdiT - Silver/black 1980 350SL - Silver/blue

08-12-2005, 11:19 AM	#5
Trekman MBWorld Fanatic! Join Date: Feb 2005 Location: Bay Area SF Posts: 1,175 Drives: Silver 2002 C32, Silver 2006 CLK 350	sound like your supercharger has gone bad.... have the dealer look at it __________________ MODS: CLK Grille, Flat emblem, 19 inch bremma, nitto 555, Mikbox, Green filters, clear corners, bi xenons 6000k bulb, Eibach springs, C55 Spoiler, Denso plugs, Manecor Wires, Eurotech Front Lip.. comming soon: Renntech chip and pully or evosport pully and chip system

08-18-2005, 10:58 AM	#6
Jon Winter Member Join Date: Oct 2002 Location: Clarksville, MD Posts: 223 Drives: C32 AMG, CLK 320	Throttle actuator or Temp sensor __________________ 02 Black C32 AMG Sold Renntech Pulley and ECU 380mm Front Brakes 322mm Rear Brakes 18" Fikse Profil 13 8.5 and 10 Carlsson RS Sport Suspension onpolemotorsports.com Summit Point Raceway > 140K miles

08-18-2005, 11:01 AM	#7
Jon Winter Member Join Date: Oct 2002 Location: Clarksville, MD Posts: 223 Drives: C32 AMG, CLK 320	I'm sorry look at the innercooler pump also. Does the car runs fine until you step on the gass hard? __________________ 02 Black C32 AMG Sold Renntech Pulley and ECU 380mm Front Brakes 322mm Rear Brakes 18" Fikse Profil 13 8.5 and 10 Carlsson RS Sport Suspension onpolemotorsports.com Summit Point Raceway > 140K miles

08-19-2005, 05:14 AM	#8
SL Boy Senior Member Join Date: Aug 2002 Location: UK Posts: 303	Yes Jon, runs fine under all other conditions. Will get it checked. __________________ Paul 2003 SL55 - Jasper blue/alpaca 2003 Smart Roadster Brabus - blue/black 2002 SLK32 AMG - lazulite blue/black 2001 E 320 CdiT - Silver/black 1980 350SL - Silver/blue

06-16-2006, 04:39 PM	#9
SL Boy Senior Member Join Date: Aug 2002 Location: UK Posts: 303	Well it has taken me all this time to sort the problem as it didnt happen at all when the outside air temperature dropped below about 25 deg C which of course it did in the UK at the end of August. With June temperatures above 25 deg again, problem returned but has now been cured. There is a water cooling jacket around the supercharger and an auxiliary water pump to redirect the cooling system water through this jacket at air temperatures greater than about 25 deg. The pump had started to fail and blown its in-line fuse. As a precautionary measure when the uncooled supercharger reached a certain temperature the ignition was automatically retarding to stop any damage occuring. So new pump and fuse fitted - problem solved. Nice to know that Mercedes/AMG engineering introduced a failsafe process here to stop major damage and expense. __________________ Paul 2003 SL55 - Jasper blue/alpaca 2003 Smart Roadster Brabus - blue/black 2002 SLK32 AMG - lazulite blue/black 2001 E 320 CdiT - Silver/black 1980 350SL - Silver/blue

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