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Discussion Starter #1
Hallo,

I have a problem with my compressor by-pass valve. It will not close.
After removing the tube to the valve I found that it can move the valve by hand if the engine is off.
With the engine running and rev it up there it's not moving. When in idle I can not move the valve by hand, so there must be some signals going to the valve.
Is there a press sensor somewhere ?

Thanks for info,
WBR Eric.
 

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Premium Member 1999 SLK 5.4 M113
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Is the Kompressor working?

I believe these will be open until you start gathering boost.. over 1200 rpm.
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
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I agree with turdo2 - be sure to check it with the RPM's above 1200.

If still not working, It could be many things - I've seen this caused by: A) broken wires and B) failed MOSFET's in the ECU.
 

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Discussion Starter #5
Goodmorning,

Thanks for your reply.
My compressor is working. Is there somewhere a wiringdiagram to find a broken wire.
There are some signals going to the valve, with ignition on ther is power at the valve. It’s commanded open.
I ll try to find a threat here for the ECU.

Thanks again, Eric.
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
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The broken wire, in my case, was one of the two wires directly attached to the bypass valve.

So your compressor engages but your butterfly won't close... that is a new one. There is a pressure sensor - green - near the elbow of the big duct that leads into the throttle valve.
 

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Discussion Starter #7
Efair,

The magnet in my comp clutch is dead for a long time. I hard wired the magnet, really dead, so I went to a fixed clutch.
Is there somewhere a trouble tree or a wire diagram for the valve? A broken wire is no problem to repair but a logic to find out what is wrong could be helpful. As far as I worked it out,it could be many thing, K40, ECU, press sensor, or the valve itself. I checked the K40 and desoldered it, no cure!

Thanks in advance,

Eric.

Damm, I love that car!
 

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Super Moderator UK SLK 55 AMG 2007
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28,156 Posts
Efair,

The magnet in my comp clutch is dead for a long time. I hard wired the magnet, really dead, so I went to a fixed clutch.
Is there somewhere a trouble tree or a wire diagram for the valve? A broken wire is no problem to repair but a logic to find out what is wrong could be helpful. As far as I worked it out,it could be many thing, K40, ECU, press sensor, or the valve itself. I checked the K40 and desoldered it, no cure!

Thanks in advance,

Eric.

Damm, I love that car!
It's best to either quote (as I have with you)
or mention a member when looking to a specific person for an answer.

Two of the mention methods:
Put '@' immediately in front of the exact username
eg @efair

Or
bracket the name [MENTlON]username[/MENTlON]
 

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Discussion Starter #9
After the winter stop there was time to “fix it”. I just made a complete fix by making it all mechanical.
The compressor pully is welded to a fixed clutch. A bid washer is installed between the airfilterbox and the bypass valve.
The hole in the washer is 20 mm. Now everything is working and the car drives fine. I got the idea for the washer from this forum.
Not the way Mercedes thought about it, but it works!

Grz Eric
 

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Discussion Starter #10
Hallo all,

On the end is was something different causing the failure. A friendly garage bought new OBD reading stuff and this one could also read OBD1. Most work shops in the EU use only OBD 2. After some trying and fiddeling the car gave, Crankshaft magnet, open. Crankshaft pos sensor, weak signal. Eng RPM sensor, on signal. And some more things I look to later.
Replaced magnet and both sensors (expensive!!!!!!) but hey. I t works!! Car starts much better, runs like h...
I suppose the RPM sensor was the one causing the bypass valve problems.

One to remember!!

WBR Eric.
 

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Hallo all,

On the end is was something different causing the failure. A friendly garage bought new OBD reading stuff and this one could also read OBD1. Most work shops in the EU use only OBD 2. After some trying and fiddeling the car gave, Crankshaft magnet, open. Crankshaft pos sensor, weak signal. Eng RPM sensor, on signal. And some more things I look to later.
Replaced magnet and both sensors (expensive!!!!!!) but hey. I t works!! Car starts much better, runs like h...
I suppose the RPM sensor was the one causing the bypass valve problems.

One to remember!!

WBR Eric.
Hello, I have the same issue.
Supercharger running but bypass valve always open.
So, are you saying that the ELM 327 doesn't recognize those fault codes, even with the 38 pin adapter?
Do you mean crankshaft or camshaft? As far as I know they should be camshaft. So, is the cam magnet related to the working bypass valve?
Thanks
 

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Discussion Starter #12
Hallo,
I replaced the two sensors and the magnet at thesame time. I suppose the cranckshaft RPM sensor did the trick, my readout was no signal from eng RPM sensor. The camshaft, weak signal. Magnet open.

Good luck,

Eric.
 
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