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Discussion Starter #1
Hello everyone,
I have 2002 SLK 200 Kompressor.

Some days it has a huge loss of power, and some days it runs perfectly. The loss of power is kind of like the supercharger is not blowing (i assume that supercharger throotle body valve is open).It accelerate smoothly without any hestitates but sloow. It never get's better while driving, only after night or 2 and then cycle repeat.

Engine warning light is off.

I cleaned carefully the MAF sensor, resolder K40 relay and no result.

Moreover i do some test. When it runs good and i disconnect MAF and sonda lambda, it runs the same good (power). When it runs slow and i disconnect, same situation.. still slow.

According to the supercharger valve, what could cause that it stays open?

I searched internet for similar problem but with no result.


Any help will be much appreciated.
 

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Hello everyone,
I have 2002 SLK 200 Kompressor.
You don't have to tell us what car you have because you completed your profile (as we ask all members to do :tu: )
 

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Except that information is not visible in mobile view...
Fair enough but that is why we tell everyone who is experiencing viewing/access problems to switch to desktop view on their cellies or tablets :tu:
 

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Discussion Starter #7
I have read all similar threads yet but my problem seems to be different. Regarding to CEL i have it and it was turning on to other problems earlier.

I did another test while slk was running well and unplugged the SC bypass valve. Then it obviously started to be weak but after i replug back the valve, slk is still weak. Is there any chance that the problem is inside the ECU? All the harness looks ok. I've read that in older slks, a common problem regarding to SC is a transistor inside the ECU but i don't think i have this one becouse the trasistor is responsible for superchargers' clutch that i don't have.
Any ideas how ECU controls the bypass valve?

Next week i'm going to plug SD somewhere.
 

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I have read all similar threads yet but my problem seems to be different. Regarding to CEL i have it and it was turning on to other problems earlier.

I did another test while slk was running well and unplugged the SC bypass valve. Then it obviously started to be weak but after i replug back the valve, slk is still weak. Is there any chance that the problem is inside the ECU? All the harness looks ok. I've read that in older slks, a common problem regarding to SC is a transistor inside the ECU but i don't think i have this one becouse the trasistor is responsible for superchargers' clutch that i don't have.
Any ideas how ECU controls the bypass valve?

Next week i'm going to plug SD somewhere.
Hi,

Pulse Width Modulated Signal from ECU.

Best way to test this is using SDS Machine ......... "Actuations", you will likely be able to step the movement as percentage, certainly can on later models, and if it is not correct as you test and observe then you can move on to more tests ..............

ABSOLUTELY NO other Machine will do this and much more.

Common problem is bad Wiring, which should be belled out from the ECU Plug to the Component, carefully inspect where the Wires go into the tiny Connectors they are known for fracturing but look ok, give them all a tug to see if the wire inside the insulation is broken :wink:

HTH, Cheers Dave
 

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SDS is indeed the best for testing, no argument there, but keep in mind SDS might be blind to failed output drivers controlling these components. Comparing the actuations it actual values to scope output would reveal it though.
 

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Randomness!

When an engine experiences random issues, it is something that fails under some operating condition but not others. If the engine runs the same with and without something, the something is OK.

Check for vacuum leaks and clean the MAF with some MAF cleaner. Also get yourself a quality scanner assuming they make one for a ride this old.

>:D
 

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When an engine experiences random issues, it is something that fails under some operating condition but not others. If the engine runs the same with and without something, the something is OK.

Check for vacuum leaks and clean the MAF with some MAF cleaner. Also get yourself a quality scanner assuming they make one for a ride this old.

>:D
Hi,

SDS >:D
 

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Discussion Starter #13
Hi again,
I did a throttle body reset procedure (ignition to 2nd position, gas pedal to the floor for 5 sec. then ignition off, pedal still pushed, and then release and wait 3 min).
After that everything seems to be fine now for 10 days.

Maybe this will help somebody else. I have no idea why this procedure has affected the problem.
 

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Please bear in mind that if the Member changes vehicles and updates their profile, the thread would appear to be referencing the wrong vehicle or even the wrong series (170, 171, or 172).






Fair enough but that is why we tell everyone who is experiencing viewing/access problems to switch to desktop view on their cellies or tablets :tu:
You don't have to tell us what car you have because you completed your profile (as we ask all members to do :tu: )
Except that information is not visible in mobile view...
 

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Super Moderator
Joined
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Please bear in mind that if the Member changes vehicles and updates their profile, the thread would appear to be referencing the wrong vehicle or even the wrong series (170, 171, or 172).
An exception to every rule :tu:

OTOH, many members leave their original/prev owned cars in their profile as:

2012 SLK 55; sold 2010 SLK 350

Just one example:
 

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