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Registered
2000 ML320 Base
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13 Posts
Discussion Starter #1
I noticed today that the air intake hose is VERY loosely connected to the rear of the intake manifold. I had a mechanic tell me yesterday that the entire plenum needed a new gasket. But, it seems as though the loose hose may be the real culprit.
Symptoms:
Rough idle, loss of power, etc. Changed plugs and all. A
Any idea?
Seems like I could put a hose clamp on it to seal it.
 

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Super Moderator
99 ML430, 00 ML320, 05 E500 4matic Wagon
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22,144 Posts
It is worth a try.
Gasket failure for the entire plenum is not a common problem unless the vehicle severely overheated
and even then the head gaskets go before the intake gaskets go.
 

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2000 ML320 Base
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13 Posts
Discussion Starter #3
Thanks for the quick response. Should the hose be loose like that? I could probably pull it off with my bare hands. The mechanic hooked it up to a smoke machine, and low and behold, that is exactly where the leak was coming from.
 

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2000 ML320 Base
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13 Posts
Discussion Starter #5
Got it...

So, I put a hose clamp on it and it runs MUCH better. But, I am still getting a slight misfire (and the gratuitous P0300, P0301, P0302 codes) in two cylinders. I have already checked the coil packs, so now I am going to switch some wires and try that. Hmmmmm. Curious.
 

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99 ML430, 00 ML320, 05 E500 4matic Wagon
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With that hose sealed up it may not be a bad idea to recheck other vacuum hoses.
It just takes a crack in one and you can get misfires.
 

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2000 ML320 Base
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13 Posts
Discussion Starter #7
Bamboozled...

Okay, so I have a new set of plug wires on the truck and I replaced the injectors for the two cylinders that were misfiring (since that seemed to be all they had in common). It runs better, but it seems like it still wants to act up when it warms. NOW WHAT! Stugots!
 

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Premium Member
02 ML320 06 ML500
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17,105 Posts
If this is the hose that you are referring to, it does not require a clamp. If either one of the arrowed clips are broken, then you need a new Air Intake Pipe.

If the clips are not broken then you need the updated seal #101. There are two different sizes, so make sure you get the correct one from the dealer.

If you suspect/think there is a vacuum leak at the intake manifold gasket, with a cold engine, lightly spray Brake Clean (NOT CARB. CLEANER) where the gasket is and if the idle raises, you have found your leak. Also spray onto #1 and 2 injectors.
 

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2000 ML320 Base
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13 Posts
Discussion Starter #9
Information request

Thanks SO much for the diagram. It has helped tremendously. Do you happen to have a list of the parts by number? I do not know what some of the parts are. Thanks.
 

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Premium Member
02 ML320 06 ML500
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17,105 Posts
Thanks SO much for the diagram. It has helped tremendously. Do you happen to have a list of the parts by number? I do not know what some of the parts are. Thanks.
Here are the part #'s, but subscribe to EPC net which is free to US citizens and you will have all the part #'s you need.

EPC-net Online
 

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2000 ML320 Base
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13 Posts
Discussion Starter #11
Now what? Bad fuel injectors?

Thanks for the info, 43sqd. Here's another puzzler: I changed the injectors on 1 and 2, but now 5 (intermittently) and 6 (more regularly) are missing. Should I have changed all of the injectors at the same time? I have tried Lucas Deep Clean already (Twice), and I use high octane fuel. By the way, I fixed the vaccum leak on the intake and it runs great- except for the now missing in 5/6. Ugh. I hate it, but I love it!
 

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02 ML320 06 ML500
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17,105 Posts
Thanks for the info, 43sqd. Here's another puzzler: I changed the injectors on 1 and 2, but now 5 (intermittently) and 6 (more regularly) are missing. Should I have changed all of the injectors at the same time? I have tried Lucas Deep Clean already (Twice), and I use high octane fuel. By the way, I fixed the vaccum leak on the intake and it runs great- except for the now missing in 5/6. Ugh. I hate it, but I love it!
Why did you change #1 & 2 injectors?

What and where was the vacuum leak and how did you fix it?
 

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2000 ML320 Base
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13 Posts
Discussion Starter #13
What is this thing?

I was installing a NEW air intake pipe and gasket on the back of the Benny tonight and I noticed this "thing" just hanging there beside the EGR valve. It looks as though the other half is missing. Anyone know what it is?
 

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Discussion Starter #14
More description...

This little "canister" is about the size of a quarter. It is located on the top of a sensor, just to the left of the intake (if you are looking at the front on the car), and beside the EGR valve.
 

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02 ML320 06 ML500
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Even though you never answered my question of 8/15, I will answer yours. If you are referring to "c" in the illustration it is a filtered air inlet and nothing is missing or broken.
 

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Discussion Starter #16
Mea Culpa...

43sqd,
Please accept my most sincere apologies for not having returned the favor of your reply. To answer your earlier questions, I changed the injectors because it seemed to be (at least to me) the only thing that the cylinders had in common. For example, I am a metaphysician, so I attempted to use deductive reasoning (which you can not use on an ML320) to determine a diagnosis and therefore formulate a treatment. Out of all the symptoms, the only thing left were the injectors. Seemed logical to me... and it did seem to work. I allegedly sealed the leak with a little gasket maker/sealer around the intake. I actually took this off last night and replaced the tube with a new one and the gasket to fit. It does seem to be a little "loose" however, but I have put it on as tightly as I could.
With regard to the EGR valve, I did some research after my post and found my error. It still seems weird to have this little thing just hanging off there, but, oh well.
Yesterday, I had the muffler and catalytic converters inspected by a muffler shop. He said that all were well, and the noisy muffler was due to the engine running "like crap". I swear there is a leak somewhere, but I just can't find it. Sometimes it runs great, other times it will sputter and backfire upon takeoff. I just don't know. The fact that the codes are so ambiguous only frustrates me more. Yes, I know that there is a random misfire and that cyls. 5 and 6 are misfiring- BUT WHY?!
Perhaps it is a leak in the plenum? I could just choke the thing.
 

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2003 ML350
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10 Posts
So what was the final solution to your misfires ? Did that also remedy the rough idle?

As a courtesy please take a few minutes and update with a reply so that others with problems that take the time to read this thread end up with a conclusion. It's a way to give back to the forum/community since others have taking the time to assist you that only seems fair.
 

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Premium Member
02 ML320 06 ML500
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17,105 Posts
So what was the final solution to your misfires ? Did that also remedy the rough idle?

As a courtesy please take a few minutes and update with a reply so that others with problems that take the time to read this thread end up with a conclusion. It's a way to give back to the forum/community since others have taking the time to assist you that only seems fair.
Your are opening multiple threads on the same issue. All misfire issues have different causes and effects. They are not all the same.

All your questions, thoughts and updates should be directed to your original post/thread, which you highjacked in the first place.

As for your present question to the above member, you can easily find out if he is active on the forum or not, buy clicking on his name and then clicking on Find more Posts by xxxxxxx, then you will find that the last time he posted was in 2012 and has not since returned.
 

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2011 E350 Coupe
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16 Posts
I do not believe 43sqd's question of 8/15 way back when was ever answered or, if it was, I did not see it. So, related to 43sqd's diagram of the air intake:

I have a similar issue related to the air intake pipe where it "connects" to the accelerator actuator (manifold). I do not believe that the bottom clip is clipping over a lip or does it go into an opening to "clip" in. Tough to see back in there. I have even replaced the boot gasket (#101), but am positive the bottom is not connecting well. How does this thing clip and what could I have broken if the pipe clip does not appear broken?
 
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