supercharger not working

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mrcgibb

Active Member
Joined
Feb 20, 2011
Messages
183
Car
230 clk w208
it looks like my 1999 230 clk supercharger hasnt worked since i got the car ......
what i have found so far..

the clutch is engaging fine and you can here the supercharger spinning ie hoover noise, but no boost....

I removed the piping from the air flap diverter beside the airbox, i tried to do a relearn function , by holding it slightly down from 90 deg , then turning ing on , then off then on for 45 second , during which time the flap is supposed to open and close to reset itself. it doesnt.

with ingnition on there is far more resistance to pushing it down from 90 deg but at no time does it close , does this indicate the valve is goosed? can anyone provide a diagram of the 3 wires going to the valve and what voltages should be present so i can check with multimeter?
 
Those bypass valves have a tendency to give up, which stops the S/c cutting in.
 
i thought that , as the clutch is engading and disengading fine around 1800 rpm , but the flap stays open , i wondered if there is a way to test to see if faulty? ie what voltage should or shouldnt be sent to it ? or weld the thing shut! joking
 
I had a poblem like that with my last 200k , it was the flap . I had codes stored in the engine ECU relating to this , have you checked for fault codes ?
 
not yet merc garage is a long drive for me and as usual busy with work but i have a question as well ?

i am 99% sure that my air divertor valve , basically a blow off valve on my 1999 clk is broken it wont close , super charger is boosting , but all pressure going back through airbox. now my question.

i have a profec boost controller i used on a saab turbo, would it be possible to remove the air divertor valve and black the holes then fit a blow off valve on the throttle side of the maf sensor , and control the blow off valve with the profec controller? does that sound doable?

the only problem i see is then the clutch isnt on with the super charger which means the car has to try and suck air through the stationary charger blades?
would it be feasable to somehow make sure the clutch is on all the time the engine is started? to get round this problem?

dont see much of these sort of posts on here to tinker with the mercs , it must be the saab turbo tinkering comming out on me lol
the air flap to me just looks like a wastgate so i cant see what problem would be caused by this ,
And why do the early cars like mine have a clutch for the supercharger and new ones the charger is on all the time? is it possible to make the clutch perm. engadged? or weld the bliter on ....
progress.gif
 
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Hi Guys

Sorry I know this is an old thread, but I am having the exact problems with my supercharger valve and was looking for help.

Recently one if my ignition coils failed and at the same time my supercharger vent flap I noticed did not seem to function properly? I replaced the ignition coil and the care drives fine, but the supercharger vetn flap stays horizontal i.e open all the time with the supercharger whine blasting through the rubber pipe.
I tried to do the reset but like others it just springs back ? do you have to hold this manualy down and get someone to turn the key? So clear instructions would be great.
As for the clutch on the supercharger this seems fine because if I disconncet the cable and reconnect it comes off and on.
 
condition of the diverter flap pcb?carbon layer thickness and resistance?
 
condition of the diverter flap pcb?carbon layer thickness and resistance?

Its process of elemination for me here. I know the by-pass flap is good as it function with the stardiagnostic and I have also bought a spare now too. You dotn get carbon the builds up as its only air that is exhaust through it, unlike the fuel throttle side, I know the MAF is okay as I have checked with another, I dont think its the crank shaft position sensor as I would have intermittent starting issue, I know the supercharger clutch is okay becuase I can disconnect and re-connect via the pulg and its not seized. All these items are linked in some way to the control of the supercharger.
SO my thoughts right now are a blown MOSFET on the ECU, which I have bought one and it should arrive tomorrow . I will solder in and see.

I will let you know if it does the trick.
 
Ok guys great news all fixed for £4.99 !
I bought the MOSFET from ebay, and went to work carefully on the ECU. Removed the old one solder the new one in, the supercharger is behaving once again !
 
Ok guys great news all fixed for £4.99 !
I bought the MOSFET from ebay, and went to work carefully on the ECU. Removed the old one solder the new one in, the supercharger is behaving once again !


Very interesting. Any photo's?
 
Very interesting. Any photo's?

The problem I had started when an ignition coil blew a couple of weeks ago, I replaced this and the car then ran smooth with no misfire. However I noticed that the supercharger was not behaving. It was always on and did not engange and disengage when you reved the engine passed 2300 rpm as it should.

I knew the MAF was okay as I tested the car with another, the crank position sensor was good as otherwise I would have issue starting. I took it to a guy I know who did a diagnostic and said that the electromagnet in the supercharger was not responding and that the whole supercharger would need replacing as you could not get the part separately.? I still was sceptical that the electro-magnet was the issue as it engaged and disengaged when I pulled the plug to the S/C . This is when I knew it had to be a 'control' signal issue.

I searched onlines forums which use the same engine, someone had talked about a MOSFET on the ECU needing to be replaced as this gives the grounding that allow the S/C to engage and disengage. So I bought one of ebay for £4.99 and replaced the one on the ECU and the Supercharger now works a treat !! It was going to cost me £400 to get a second hand unit fitted, what a waste that would have been!

I am not taking the credit here as thanks goes to the ones that figured the scource of the issue, which got me in the right direction !

If your interested I have added some photos and videos of the results....

Mercedes CLK 230 supercharger engaging and disengaging - YouTube - Testing the MOSFET for the 1st time.
https://www.youtube.com/watch?v=vyhX5MpRz18 - By pass valve functioning gain.
https://www.youtube.com/watch?v=CfwbUv4Ybb0 - Out for a drive with Supercharger on.
 

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cool a1ek, smart and cheap repair. when I was talking about the carbon layer I meant thr resistor layer on my pcb inside the diverter.it is a carbon layer like a potmeter. traveling distance of the contact copper gives a certain resistance to the ecu to decide position.
 
I cut the legs off and re-solder onto them to save any damage to the PCB.

But those ECU's are pretty sturdy stuff :)






.
 
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