supercharger question - Mercedes Benz SLK Forum

SLK R170 General Discussion SLK 200, SLK 230K, SLK 320, SLK32 AMG

 
LinkBack Thread Tools
#1 Old 01-27-2014
Registered Users
 
Join Date: Dec 2013
Location: SC
Vehicle: 2000 SLK 230
Other Toys: 09 Kawisaki Concours 14
Posts: 83
Country:
Chats: 0
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 2
Thanked 5 Times in 5 Posts
(Thread Starter)
supercharger question

clutch bearing is rattling some, clutch magnet ingaged all the time. 186xxx on the car. was thinking of diy rebuild but with weather and no where inside to do it I was thinking of replacment.

found a place to get a rebuild one with core exchange but they say that the mag clutch must be working on the core. I read somewhere that if you can manually turn the mag clutch with your hand that the mag clutch is ok and the problem is somewhere else in the system.
can anybody comfirm this????? or is there another way to test it???

I tryed it and I can turn it by hand. so what does the group say????
gonzosc1 is offline  
Sponsored Links
Advertisement
 
#2 Old 02-04-2014
Premium Member
 
JiminFL's Avatar
 
Join Date: Sep 2013
Location: Tampa Bay, FL
Vehicle: 2011 SLK300 with smart top
Other Toys: 2012 GLK350, 1970 Jaguar E-Type
Posts: 427
Country:
Chats: 0
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 39 Post(s)
Thanks: 64
Thanked 63 Times in 55 Posts
Garage
I believe the clutch is like the one on the a/c compressor. (I don't have the clutch on mine so I can't go out to the garage to check it.) If it is the same, the clutch will spin 'cause it is connected to the s/c shaft. If it is rattling and not engaging, then it probably is the magnet which pulls it in to the belt pulley or the pulley bearing itself. That should not be a problem to diagnose and fix.

While the car is off, unplug the wire from the magnet & jumper that wire that comes from the magnet to the battery + terminal. The clutch should snap in audibly and visually. Now, try jumping it with the car running. Should do the same thing and get the s/c spinning and it should stop spinning when the +12v is removed from the wire.

If that is the case then look for the reason why there is +12v being applied to the clutch whenever the key is on. Any weird noises or other strange behavior will need further investigating. If the pulley bearing is bad, it should make noise all the time, but in a rare case it may only make noise if it is puled out of alignment by the magnet. Get a stethoscope and listen carefully to everything in that area. Hope this helps.

Last edited by JiminFL; 02-06-2014 at 10:00 AM.
JiminFL is offline  
#3 Old 02-04-2014
Registered Users
 
Join Date: Dec 2013
Location: SC
Vehicle: 2000 SLK 230
Other Toys: 09 Kawisaki Concours 14
Posts: 83
Country:
Chats: 0
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 2
Thanked 5 Times in 5 Posts
(Thread Starter)
thanks Jim, I will try that hopefully this weekend.
gonzosc1 is offline  
 
#4 Old 02-04-2014
Registered Users
 
Join Date: Oct 2011
Location: Riverside
Vehicle: 09' SLK55 w'AMG Performance Package
Posts: 500
Country:
Chats: 0
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 2
Thanked 96 Times in 65 Posts
Quote:
Originally Posted by gonzosc1 View Post
clutch bearing is rattling some, clutch magnet ingaged all the time. 186xxx on the car. was thinking of diy rebuild but with weather and no where inside to do it I was thinking of replacment.

found a place to get a rebuild one with core exchange but they say that the mag clutch must be working on the core. I read somewhere that if you can manually turn the mag clutch with your hand that the mag clutch is ok and the problem is somewhere else in the system.
can anybody comfirm this????? or is there another way to test it???

I tryed it and I can turn it by hand. so what does the group say????

For the pre-2000 models Slk230 with SC clutch, open your hood, at idling, you can see the SC is not spinning, then rev the engine above 2500 rpm, your SC should come on. You can see see the clutch engaged and hear it too.
Klinh is offline  
#5 Old 02-05-2014
Registered Users
 
Join Date: Dec 2013
Location: SC
Vehicle: 2000 SLK 230
Other Toys: 09 Kawisaki Concours 14
Posts: 83
Country:
Chats: 0
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 2
Thanked 5 Times in 5 Posts
(Thread Starter)
Quote:
Originally Posted by Klinh View Post
For the pre-2000 models Slk230 with SC clutch, open your hood, at idling, you can see the SC is not spinning, then rev the engine above 2500 rpm, your SC should come on. You can see see the clutch engaged and hear it too.
I said the clutch is engaged all the time. the face of the pulley is spinning all the time. always on so I hunting ways to test it. I just found a thread where someone had to replace a mosfet in one of the control boxes to fix it. I'm hoping its something simple like that.
gonzosc1 is offline  
#6 Old 07-18-2015
Premium Member
 
Join Date: May 2010
Location: Atlanta
Vehicle: 2005 SLK 55; 2005 SLK 350
Other Toys: Several past R170's
Posts: 4,315
Country:
Chats: 0
Mentioned: 595 Post(s)
Tagged: 0 Thread(s)
Quoted: 913 Post(s)
Thanks: 155
Thanked 520 Times in 481 Posts
I have a 99 230 that was doing the same thing - SC constantly engaged. I googled this and compared to some working cars... And I decided to try the MOSFET replacement. It did stop the constant engagement - the SC doesn't engage at idle any more (which is good, and validates the problem is the motronic) but it doesn't seem to want to engage at all now (which is bad). The best I can get out of it is a few turns when I rev it up - nowhere near the positive engagement it is supposed to have.

So I'm thinking maybe I didn't solder the replacement MOSFET in well enough, or I damaged the new one during the replacement.

Interestingly, I measured battery voltage at the SC connector... I'm wondering if the motronic uses a PWM signal to engage it.

Also I've heard there is a reset procedure for the bypass valve - has anybody here used that procedure?
efair is offline  
#7 Old 07-19-2015
Premium Member
 
Join Date: May 2010
Location: Atlanta
Vehicle: 2005 SLK 55; 2005 SLK 350
Other Toys: Several past R170's
Posts: 4,315
Country:
Chats: 0
Mentioned: 595 Post(s)
Tagged: 0 Thread(s)
Quoted: 913 Post(s)
Thanks: 155
Thanked 520 Times in 481 Posts
Answering my own question here -- the ECU provides the ground to the SC clutch - not the +12V. So the fact I can measure +12V at the clutch connector is irrelevant.
efair is offline  
#8 Old 07-28-2015
Premium Member
 
Join Date: May 2010
Location: Atlanta
Vehicle: 2005 SLK 55; 2005 SLK 350
Other Toys: Several past R170's
Posts: 4,315
Country:
Chats: 0
Mentioned: 595 Post(s)
Tagged: 0 Thread(s)
Quoted: 913 Post(s)
Thanks: 155
Thanked 520 Times in 481 Posts
No joy still, and a bunch of dumb questions related to bypass valve and ME-SFI

I re-soldered the MOSFET but I'm still seeing the same result - one weak revolution then the SC disengages.

I found a procedure for "resetting the bypass valve", but it's unclear exactly how to do it. Supposedly this is in SSM - can any of you with SSM find this procedure? It would be nice to know 1) What position the valve should be in to start the procedure, 2) How far I'm supposed to manually turn the valve with my finger, 3) At what point I'm supposed to remove my finger, and 4) What I should expect to see if it works as expected.

(I'm also not sure how the reset procedure knows that I'm holding the valve with my finger -- is there some sensor that tells it this?)

Also, if anybody has a wiring diagram for the 99 ME-SFI - that would be most helpful too (so I can diagram what *all* the MOSFET's are for, not just the one MOSFET for the SC clutch).
efair is offline  
#9 Old 07-30-2015
Premium Member
 
Join Date: May 2010
Location: Atlanta
Vehicle: 2005 SLK 55; 2005 SLK 350
Other Toys: Several past R170's
Posts: 4,315
Country:
Chats: 0
Mentioned: 595 Post(s)
Tagged: 0 Thread(s)
Quoted: 913 Post(s)
Thanks: 155
Thanked 520 Times in 481 Posts
OK - end of story - The SC is working great now. Two problems at once.

First, the MOSFET was indeed bad, that's why the SC clutch was constantly engaged. This was surprisingly easy to fix given my kindergarten soldering skills. I did employ ESD protection (if you try this repair, you should too -- cost about $15 USD).

However, after replacing the MOSFET, the SC clutch wouldn't stay engaged. It would engage briefly at the prescribed times but then stop after maybe one revolution.

Second, there was a broken wire to the bypass valve. Apparently the clutch is disengaged when this particular wire is broken. I do wonder if the Motronic is making this decision digitally, or if there's something analog making this happen.

I don't have an accurate 99 wiring diagram for this part (M16/7) so I don't know what this wire is.

The key to finding the broken wire was to disconnect the air hose from the bypass valve so you can see the valve, and then watch it during startup. Comparing it to a working unit was helpful... When revving the engine the butterfly valve should clearly open and close and basically be moving a good bit. In my case, no motion at all no matter what. Further inspection led to the broken wire.
efair is offline  
Sponsored Links
Advertisement
 
Reply

  Lower Navigation
Go Back   Mercedes Benz SLK Forum > Mercedes Benz R170 SLK Class Cars > SLK R170 General Discussion

Bookmarks

Quick Reply
Message:
Options
Upload your files to MEGAUPLOAD
Upload your images to ImageShack

Register Now



In order to be able to post messages on the Mercedes Benz SLK Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Kleemann Supercharger and Air filter question Tiremarx723 Performance MODS for the R171 1 01-21-2013 04:49 PM
Supercharger Lag Question. MercedesOwner230 SLK R170 General Discussion 5 10-12-2012 08:21 PM
supercharger question William65 SLK R170 General Discussion 3 12-13-2011 08:17 PM
Supercharger question recker SLK R170 General Discussion 34 01-08-2009 07:10 PM
Question about the supercharger twitch_de SLK R170 General Discussion 17 07-29-2008 01:56 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 

Clubs, Garage Plus vBulletin Plugins by Drive Thru Online, Inc.