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'07 S550 Designo Mocha, '07 S600 Saks edition, '09 R350
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Discussion Starter · #1 ·
Two weeks ago I did a plug change on my '99 E430 (95k miles) with the instructions here on the board (thanks C-AMG!). I used OE Bosh Platin plugs.

After about 6 hours of work my car ran perfectly smooth. However now two weeks later I'm noticing the same rough idle that got me to change the plugs in the first place. I certainly wouldn't classify it as an incredibly rough idle but you can tell it's missing here and there.

I also feel I like I hear a light ticking sound from the drivers side of the engine that wasn't there before. I tightened the plugs to spec with a good torque wrench. But getting the wires on the drivers side was quite a chore.

I've gone back and check the wires and everything seems okay. I also still have the old plugs if anyone would like to see pictures.

Any tips to diagnose are appreciated. Also I have a friend with a OBDC II tester, is there anything it could tell me even though there is no check engine light?

Thanks!
 

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2001 E320 - Brilliant Silver/Ash: 107,000+
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Yes, there can be codes stored without seeing a Check Engine Light so as a next step I would have the scanner look for any. Good Luck!
 

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1994 E320 Wagon,1999 E320 Wagon,2000 E 320 Wagon, MGB Track/Rally, ,1988 300E ,more....
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6,019 Posts
Did

you leave the wires on the coils and just remove them at the spark plug boot end?
did you use the special 17mm offset plug boot tool like I sell for $28 delivered?
Scan for pending codes look for p0300 and any other p03** codes and report them here.
If you pulled the boots off with anything other then the 17mm you may have damaged a wire or without the 17mm it is hard to make sure the boot is popped back onto the plug correctly.
THe cps(crank position sensor)will note even a minor misfire condition and store a code or if often enough will trip the light.
so check the wires are firmly popped on at coil and at boot.You did make sure upper wire front plug lower wire rear plug on each cylinder,correct?
What plug did you use?
The clicking sound you hear sounds like a very crisp ultra quick snap?if so could be a wire arching a spark.
get back to us with the results:thumbsup:
ohlord:bowdown:
 

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'01-E320 & 02-ST2
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Hey, jshood, welcome to the forum. Please update your profile for car and location details, that can be useful information.

There could be a few different things going on here...in random order:

First, did you use dielectric grease in the caps? That makes the plug wire caps go on fully and easier, which is lots more important in the closer confines on the drivers' side. If the sound you're hearing is an arcing, that could be part of the issue.

Second, are you completely sure you did not hear the noise previously? It's human nature to think you hear something new when you're trying to chase an issue, so think hard about that one. For example, the purge valve makes an interesting light clatter, so...

Third, speaking of human nature, it's typical that when you've worked that long and hard on something for your mind to fool you, so that the rough idle you thought was gone was actually still there.

Fourth, is the rough idle just the same as it was before (at least to the best of your knowledge and memory)?

Fifth, it is possible for pending codes to be stored without illuminating the CEL, so definitely plug in the OBDII reader and see what it tells you.

Sixth, at 95,000 miles you were due for plugs anyway.

Seventh, have you already changed your motor mounts?

One possibility here is that your motor mounts were failing and that is what you were feeling. Given the mileage it's natural to guess the plugs, but it's entirely possible that while you thought plugs -- and again, they were due anyway -- it wasn't plugs. When my motor mounts first started to fail there were times I would not feel them at all and everything was nice and smooth; it wasn't a constant thing, that's why I'm leaning that way. Of course if you have already changed the motor mounts that's unlikely.

So those are just a few things to mull over before you dive back in.

Good luck and keep us posted.

Take care and enjoy the ride,
Greg
 

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2002 e320 4 Matic Wagon
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364 Posts
Two weeks ago I did a plug change on my '99 E430 (95k miles) with the instructions here on the board (thanks C-AMG!). I used OE Bosh Platin plugs.

After about 6 hours of work my car ran perfectly smooth. However now two weeks later I'm noticing the same rough idle that got me to change the plugs in the first place. I certainly wouldn't classify it as an incredibly rough idle but you can tell it's missing here and there.

I also feel I like I hear a light ticking sound from the drivers side of the engine that wasn't there before. I tightened the plugs to spec with a good torque wrench. But getting the wires on the drivers side was quite a chore.

I've gone back and check the wires and everything seems okay. I also still have the old plugs if anyone would like to see pictures.

Any tips to diagnose are appreciated. Also I have a friend with a OBDC II tester, is there anything it could tell me even though there is no check engine light?

Thanks!
Is your car running better? Have you solved your problem?
 

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Premium Member
2001 E320 - Brilliant Silver/Ash: 107,000+
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17,193 Posts
Do you have an update

Is your car running better? Have you solved your problem?
+1 with Hi Fi.

jshood,

This thread was started May 3rd and you have not come back with any updates. There are evidently a few members who are interested in the outcome, including me.

Thanks,

MM
 

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'01-E320 & 02-ST2
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MB E420T
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hi guys

i would like to know the outcome too...
had same issue
changed plugs but it's still shaking
got p0303 and p0300 codes.like ohlord mentioned -error with cylinder 3...(yet, could it be any other?)
i did not really feel the rubber coil "pop" onto the spark plug..... could this be it?
also, i did not use a torque wrench (store was closed and i was in a rush -forgive me), could it be that i bolted the plugs down to far/hard and as such, they sit about 1mm too low and therefore the coil does not fit strong enough on there to pass on the signal?
i will open them all up and "untighten" them a little just to be sure... did it with cyl3 this morning and ran better already... yet not 100% yet.
so, will be another 90min work...

thinking out loud... thx to the experts for help....
 

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2003 Mercedes Benz E500
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668 Posts
Your car...

hi guys

i would like to know the outcome too...
had same issue
changed plugs but it's still shaking
got p0303 and p0300 codes.like ohlord mentioned -error with cylinder 3...(yet, could it be any other?)
i did not really feel the rubber coil "pop" onto the spark plug..... could this be it?
also, i did not use a torque wrench (store was closed and i was in a rush -forgive me), could it be that i bolted the plugs down to far/hard and as such, they sit about 1mm too low and therefore the coil does not fit strong enough on there to pass on the signal?
i will open them all up and "untighten" them a little just to be sure... did it with cyl3 this morning and ran better already... yet not 100% yet.
so, will be another 90min work...

thinking out loud... thx to the experts for help....
has a very different setup form the E430, with a single spark plug/cylinder and top mounted coil packs.

The "boot" connectors in the M119 are known to be troublesome when they age. I would suggest you go back and 1) properly torque the plugs, 2) inspect the boot connectors, 3) replace any that are not up to snuff and 4) properly torque the coil pack bolts upon re-installation as over-tightening these can cause the case to crack at the anchoring points.

This should [hopefully] get your car running well...

Good luck.

JT
 

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MB E420T
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sry, you are right... misread it for an E420...
thx for the response though... am doing so and hope to get smooth ride again.
technical inspection is tomorrow and u know ze germans, zey are strict with an eye for detail ;) Xing my fingers
 

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2002 e320 4 Matic Wagon
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364 Posts
hi guys

i would like to know the outcome too...
had same issue
changed plugs but it's still shaking
got p0303 and p0300 codes.like ohlord mentioned -error with cylinder 3...(yet, could it be any other?)
i did not really feel the rubber coil "pop" onto the spark plug..... could this be it?
also, i did not use a torque wrench (store was closed and i was in a rush -forgive me), could it be that i bolted the plugs down to far/hard and as such, they sit about 1mm too low and therefore the coil does not fit strong enough on there to pass on the signal?
i will open them all up and "untighten" them a little just to be sure... did it with cyl3 this morning and ran better already... yet not 100% yet.
so, will be another 90min work...

thinking out loud... thx to the experts for help....
How are things going ? Are your codes gone? Is it still shaking? Please keep us posted if you solved the problem.
 
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