missfire problem
Thread Starter
Member
Joined: Sep 2002
Posts: 235
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From: VA
2002 SLK 32 AMG
missfire problem
hey guys i have a slk 32 amg. last week i had the check engine light come up on me when i wot it on the highway. it happened twice. took it to the dealer and they said it was missfiring. so they checked the spark plug wires and the coils and said they were fine. they also replaced the fuel filter and cleaned out my fuel rail. but when they took it out on a road test the check engine light came back on and it was missfiring again. they said the only thing it could be was my spark plugs. i have the ik20's in my car. is that at the same heat range as the stock ones or are they colder?? if they are colder than stock will that make my car missfire because of the colder weather too. it's like average 50 degrees around in VA.
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From: Houston
C63S
hey guys i have a slk 32 amg. last week i had the check engine light come up on me when i wot it on the highway. it happened twice. took it to the dealer and they said it was missfiring. so they checked the spark plug wires and the coils and said they were fine. they also replaced the fuel filter and cleaned out my fuel rail. but when they took it out on a road test the check engine light came back on and it was missfiring again. they said the only thing it could be was my spark plugs. i have the ik20's in my car. is that at the same heat range as the stock ones or are they colder?? if they are colder than stock will that make my car missfire because of the colder weather too. it's like average 50 degrees around in VA.
Is it the same cylinder that misfires each time?
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Joined: Mar 2006
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From: Ohio
...
agreed! it is not the plugs, like jerry said, they are the same heat range as stock...i would start with plug wires...
Thread Starter
Member
Joined: Sep 2002
Posts: 235
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From: VA
2002 SLK 32 AMG
each time it missfires they are different cylinders. my serv. rep told me that it wasn't the wires or the coils. he said that they switched each one out to see if there was a bad one, but they were all good. so now i don't know what it could be?? any other suggestions?
thanks guys for the fast reponse.
thanks guys for the fast reponse.
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Joined: Mar 2006
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From: Ohio
...
each time it missfires they are different cylinders. my serv. rep told me that it wasn't the wires or the coils. he said that they switched each one out to see if there was a bad one, but they were all good. so now i don't know what it could be?? any other suggestions?
thanks guys for the fast reponse.
thanks guys for the fast reponse.
i would also bet money that they won't want to replace it...but i will hope for the best for you, hopefully they are willing to make your car whole again...
Thread Starter
Member
Joined: Sep 2002
Posts: 235
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From: VA
2002 SLK 32 AMG
it is your engine wiring harness...i would bet money on it, as Jerry can atest to, this has been a documented problem before...
i would also bet money that they won't want to replace it...but i will hope for the best for you, hopefully they are willing to make your car whole again...
i would also bet money that they won't want to replace it...but i will hope for the best for you, hopefully they are willing to make your car whole again...
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From: Ohio
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i don't know on cost...sorry
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From: Houston
C63S
I thought about this yesterday and I now think that it could be a faulty sensor. I believe that a faulty crankshaft position sensor or camshaft position sensor could cause the random misfire.
However, if I remember correctly, your car wouldn't start if either sensor was faulty. If the sensor appears normal during start up, then goes faulty, I'm sure the misfire would happen. I would also expect to see a code stored or pending as well.
If there are no codes other than the random misfire code, then I'm still leaning towards the engine harness.
As Erick stated, it is a documented problem with the W203.
Do you have access to an ODBII code reader? If not, then get one. You need to be sure of the problem before you bring it in for service.
I would also try removing the coil packs and cleaning the contacts on the engine harness. Secondly, try some basic troubleshooting over the next few days. Get the OBDII reader and wait for the misfire to happen. After you know which cylinder, write it down, then swap coil packs / ignition wires with a known good cylinder. Clear the codes and wait for it to happen again. Then repeat the process a few times. If the misfire follows the coil / ignition cable, then you have the problem figured out.
I know you said MB looked at it, but it my experience, they are good parts changers and poor troubleshooters.
Sorry bro, but this will require some work on your part.
However, if I remember correctly, your car wouldn't start if either sensor was faulty. If the sensor appears normal during start up, then goes faulty, I'm sure the misfire would happen. I would also expect to see a code stored or pending as well.
If there are no codes other than the random misfire code, then I'm still leaning towards the engine harness.
As Erick stated, it is a documented problem with the W203.
Do you have access to an ODBII code reader? If not, then get one. You need to be sure of the problem before you bring it in for service.
I would also try removing the coil packs and cleaning the contacts on the engine harness. Secondly, try some basic troubleshooting over the next few days. Get the OBDII reader and wait for the misfire to happen. After you know which cylinder, write it down, then swap coil packs / ignition wires with a known good cylinder. Clear the codes and wait for it to happen again. Then repeat the process a few times. If the misfire follows the coil / ignition cable, then you have the problem figured out.
I know you said MB looked at it, but it my experience, they are good parts changers and poor troubleshooters.
Sorry bro, but this will require some work on your part.
Last edited by sales@eurocharged.com; Nov 21, 2007 at 08:48 AM.
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Joined: Mar 2007
Posts: 510
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From: dayton ohio hopefully it will be some place warm and sunny when i finish med school
2002 C32 AMG silver & 2003 Lancer Evolution 8 black very moded
its your plug wires... its EXTREMELY RARE to have a coil go wrong ... PLUGs trust everyone on here
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c55
have u checked the fuel? I know you had the fuel filter replaced and fuel rail cleaned, but have u checked the fuel in the tank? ive seen it on two different mercedes with the same symptoms youve described and both cases were sugar in the gas tank.
Thread Starter
Member
Joined: Sep 2002
Posts: 235
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From: VA
2002 SLK 32 AMG
how do i check my fuel??? and how do i know if sugar is in it.
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Joined: Apr 2007
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300E a couple 1994 w124wagon E320 Wagon/,1971MGB Track/Rally, MG Midget Autocross ,2000 E320 wagon.
Get
the codes and post them.
http://www.harborfreightusa.com/usa/...te.do?state=VA
obd2 code reader#94169 39 bucks ,the store will meet the internet price if you ask them.Reads codes clears them and shows i/m status for smog tests.
If you post the codes a solution path will at least get you headed in the correct direction.
http://www.harborfreightusa.com/usa/...te.do?state=VA
obd2 code reader#94169 39 bucks ,the store will meet the internet price if you ask them.Reads codes clears them and shows i/m status for smog tests.
If you post the codes a solution path will at least get you headed in the correct direction.
Super Member
Joined: Mar 2007
Posts: 510
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From: dayton ohio hopefully it will be some place warm and sunny when i finish med school
2002 C32 AMG silver & 2003 Lancer Evolution 8 black very moded
my gas tank door locks... when i lock my car... and when i had the fuel system flushed the tank is apart of that... it gets cleaned out as well. but if you had sugar in your tank your fuel lines will get backed up over time and then you would have more serious issues in the engine itself.... not just a misfire problem... you would have rough idle but alot more stuff going wrong as well... no throttle response, MPG would drop you would need a new fuel filter more often...
Super Member
Joined: Mar 2007
Posts: 510
Likes: 1
From: dayton ohio hopefully it will be some place warm and sunny when i finish med school
2002 C32 AMG silver & 2003 Lancer Evolution 8 black very moded
you dont have sugar in your gas tank... take it to a shop that does fuel system flushes... and tell them you want the gas tank checked for sugar... LOL b/c dont forget that the fuel pump on your car will get clogged up oh and you wont be able to start your car
Super Member
Joined: Mar 2007
Posts: 510
Likes: 1
From: dayton ohio hopefully it will be some place warm and sunny when i finish med school
2002 C32 AMG silver & 2003 Lancer Evolution 8 black very moded
the codes and post them.
http://www.harborfreightusa.com/usa/...te.do?state=VA
obd2 code reader#94169 39 bucks ,the store will meet the internet price if you ask them.Reads codes clears them and shows i/m status for smog tests.
If you post the codes a solution path will at least get you headed in the correct direction.
http://www.harborfreightusa.com/usa/...te.do?state=VA
obd2 code reader#94169 39 bucks ,the store will meet the internet price if you ask them.Reads codes clears them and shows i/m status for smog tests.
If you post the codes a solution path will at least get you headed in the correct direction.
MBWorld Fanatic!
Joined: Apr 2007
Posts: 6,171
Likes: 16
300E a couple 1994 w124wagon E320 Wagon/,1971MGB Track/Rally, MG Midget Autocross ,2000 E320 wagon.
he
has harborfreightstores all over Va. so he can just walk in and pick up the obd2 w can for 39 bucks,but if he wants to he can spend more at autozone for a reader that does less,that's a good idea also.
