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.

 

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.

 

It will come off by hand, but should not fail a smoke test.

 

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.

 

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.

 

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!

 

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.

 

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.

 

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

 

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!

 

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?

 

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?

 

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.

 

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.

 

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.

 

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.

 

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?

 

When you snap the pipe on. the lower clip grabs the lip of the actuator.

 

Thanks. The clip on mine does not have enough spring left to grab it. I suppose that I need a new pipe, so ordered one tonight. Hopefully that will take care of my leak issue. Will post an update after I get the part and replace.

 

The next time you have to remove that pipe, remove everything that is holding it down and then with your left hand gone under the pipe and with your thumbnail release the clip. Do not use a screwdriver as the instructions suggest.

 

Did you get new sealing ring for it also? It is an improved/updated part.

 

Thanks Noodles. I did get a new ring (boot, I believe the description called it on FCPEuro.com, $10.99). It fit into the old intake pipe perfectly and is a Mercedes brand. I have ordered a new intake pipe (also FCPEuro.com, 107.99) because I suspect that I overly manhandled the intake pipe off of the actuator by not pulling down the clip in the first place; or possibly from taking the pipe off some many times over the last two months, I have diminished the "spring" capacity on the plastic strap/clip piece. It does not seem to be clipping at all over the lip of the actuator.

 

Quick update, the new intake pipe did clip over the lip tightly, so that is better. Unfortunately, I still have the giant plume of smoke about every 20-40 miles, depending on the type of driving and there is a significant loss of power. I am also burning a lot of oil, some dripping out of the tail pipe after the plume of smoke and the exhaust pipe is black. I suspect rings, but the odd thing is that there was no smoke and very little oil burning just prior to the intake pipe and vacuum hose removal, ie it all started after the removal and replacement of these to locate a suspected vacuum leak. I guess it was to much wishful thinking that I missed a tight connection or broke a hose....I will just take it to MB to get an analysis, unless I get another idea here. No codes are on right now, but have been PO301, 302, 304, 305, clear those and then may get a PO150 with no PO301, etc.

 

but the odd thing is that there was no smoke and very little oil burning just prior to the intake pipe and vacuum hose removal, ie it all started after the removal and replacement of these to locate a suspected vacuum leak.

How soon after?


Did you remove any of the #164 valves? You could have reinstalled them backwards.

 

Perhaps a cylinder leak down test could help you determine the status of the rings and the possible of compression allowing oil blow by.

 

You should remove the spark plugs and see which ones are oil soaked.

 

I just got the ML320 back from Mercedes Manhattan today and the verdict is that an engine rebuild is needed. I am going to sell the truck as junk. If anyone knows of the best way to get rid of, please let me know.

 

Like the old Johnny Cash song "One Piece At A Time" if you have the time, space and tools to do it.
Otherwise a scrapyard is only going to pay maybe $500 dollars for it as a whole vehicle with the title.

 

You are right Noodles, $450 was the offer! 43sqd, the smoke just randomly happened after about 20 minutes of driving from the reinstall of air intake pipe (which obviously never "clipped" to connect. I did not replace the #164 's until the third replace and re-install, so the smoke plume was already happening before those were replaced. Thanks for all the attention.