Thanks, will do. Do you think it is safe to drive while I wait for a cover? Or should I avoid that?

Also, FWIW, my cap was not bouncing until I made this change. So I guess that may be more of a good thing?

 

"Safe to drive"?

What is exactly the issue? From going back it seems you say "There was a small amount of oil in the body throttle and idle is a bit rough. I drives well otherwise.". And now after replacing a few things the oil cap bounces and the idle is still not smooth.

Not sure I would go ahead and replace the valve cover, unless it is obviously leaking oil. I was just watching a video from FCP on the M271 valve cover replacement and they say the main reasons to replace is leaking valve cover gasket which allows oil out and debris inside the engine, another reason is oil leaking around the spark plugs.

I know working on my M272 engine that a little bit of oil making its way to the throttle body is just something that happens. I replaced the passenger side oil drip pan and breather cover and when I check I still find a bit of oil making its way down the hose. The old parts were in good condition and I probably wasted my money doing the work but since I had pulled the cover that gasket is no longer good so I had to install the new one. Then I figured that it must be the drivers side breather cover so i removed it and took it apart, nope that was also in good condition with no oil in it. I was able to re-install that and return the new one I had bought.

Have you scanned the car?

 

@jeiholzer - when I get back to my car I’ll post another video. I think the oil cap bounce is normal when it’s pulled completely off.i checked a few different cars that were for sale when I was investigating this issue. Every one of the cars had the oil cap bounce. I was learning as I went so I only checked for the bounce. Not the suction. One cars engine was completely sludged up with oil. Ran really rough.

You should feel it get sucked in when placing it back on the threads.


im not a professional mechanic but it’s your call. you should be fine. I drove my car on a road trip before I replaced the PCV system. (Not knowing I had an issue) my car was leaking oil from the valve cover and OFH, from the built up crankcase pressure.

im with Tim, you should scan your car with a Mercedes grade scanner regarding the rough idle. Oil in the throttle body and intake is normal. Excessive is not.

does your valve cover seem to be leaking anywhere around the edge or ignition coils/spark plugs ?

 

Ok, I was thinking the same that maybe replacing the VC might not necessary fix my issue. So let's back up as you did.

Initially I was seeing hesitation, step on gas and it did not immediately take of. And idle was a little rough, more vibration that I feel like there should be, sometime a very slight dip in rpms but overall not bad. I did get a misfire in 4 once. That is what kicked this off. To test the spark plug vs coil I swapped the 3 and 4 coils.I Did not get the misfire again but the rest remained.

What I did at that point was clean the boost sensor, both map sensors and the throttle body. I never got the misfire again, the hesitation went away, and it idled a little better. So in some ways I feel like doing just that was 'enough'. But I feel like the hesitation is beginning to return a bit. I do know that some oil in the throttle body is ok but I can't help but feel like maybe after more gets in there it will just need to be cleaned again.

That is why I got into looking for a PVC as that seemed to fit. And then the oil separator. But then reading those posts it got me thinking about the low pressure system also. I choose to only do the low pressure and not the VC because I was not seeing the oil cap dance. Now I do and I am still wondering about the oil separator build into the VC.

That is why I am where I am. But I don't have the technical knowledge to diagnose something different. I have not scanned the car other than looking for codes. The reader I have will show me some of the sensor values as it is running. Is there something specific you think I should be looking at? I guess I really need to suck it up and get a better scanner as you discussed earlier.

I am asking about it being safe to drive because my wife is concerned. Not to be mean though she is bit of a worrier. I know neither of you can really answer that question but I was hoping for a gut feeling. And hoping you would not say hell no don't drive it no matter what you do. My feeling is that whatever is up has been up for some time no and if something catastrophic was going to happen it woudl have happened by now. And though I may not have the best reader that at least some code would have thrown by now. It drives well right now. It is more that the idle is rougher than I'd like.

Ok, now I am just rambling. I cleaned all that stuff, sensors and throttle body, when replacing low pressure hoses and idle seems the same or actually maybe a little worse. Maybe I did not put something back well enough? Maybe fixing that is causing something else to be exaggerated?

What do you think I should look for with the scanner while the engine is running? I'll see if my scanner reports it. If not really may just have to buy a better one.

 

I am sorry, I wish that I was more technically inclined and could give you better answers. I don't want to waste your time. You both have already been so helpful.

 

I enjoy trying to figure things out, I may have the same issue some day so its good to find answers.

I dont have much experience with obd scanners since I typically do not need to use it. I just wanted something that is capable of working with my Mercedes just in case. My $15 obd reader wasnt capable. Based on searching around and reading reviews if i had to get a scanner today I would get one of the Launch Creader scanners. I would get the Creader Elite V2.0 because I like the horizontal screen over the Creader Elite with vertical screen. I do like my Foxwell NT530 and it does tons of things, its just not touch screen, thats my only complaint.

Im guessing all the Creader scanners run the same software so are all capable of doing the same things. Price difference comes with different options, different operating systems which im also guessing makes higher priced ones faster. Seems the $200 + models also work with BMW, VW and Audi.

- Creader Elite Android 5.0 with 4" vertical touch screen.
- Creader Elite V2.0 Android 8.1 with 4" horizontal touch screen.
- X431 Elite V2.0 Android 8.0 with 4" horizontal touch screen. BMW, VW, Audi
- X431 Creader Elite 2.0 Android 8.1 with 3.97" horizontal touch screen. BMW, VW, Audi

Amazon has the Creader elite for only $119.

Can find them even cheaper if you look around.








As far as rough idle, I notice mine runs a little rough once in awhile. Nothing major, just more that it is not running perfectly smooth at stop lights. Most times I put a bottle of techron in the gas tank and it seems to go away and i dont notice it anymore. I also look at my gas mileage routinely, when my car is running perfectly im getting around 27mpg if im on the highways, backroads its around 23mpg. I'm always scanning the car just for fun. I do get random stored codes once in awhile so i take photos of the screen then erase the codes. I think its good in general to keep track of anything popping up. One code that keeps showing is for the wiper motor, which works fine so not sure what that is about.

Back to the techron, I dont usually get Tier 1 gas, I get Gulf which I dont seem to have issues with, but thats why I use the techron once in awhile. Just from my small engines I know gas goes bad and can really clog things up, which is why I always use seafoam when I fill my gas containers.

With the engine running in park put your hand on the air box, is it vibrating like crazy, or smooth? When I got my car back from the hack shop recently my engine was vibrating like crazy, i thought something was really wrong. I checked the engine mounts and they seemed fine, went for a long trip on the highway and sure enough it went away. I also filled with Mobil just because it was the first gas station I came across.

Unless your check engine light is on I dont think there is anything to worry about, and you will probably notice something is wrong. Even with the check engine light on its usually fine to drive, its when it starts flashing is when you should pull over.

Have you kept up with all the recommended maintenance? I look thru my maintenance manual that came with the car and make sure everything is done up to date/mileage. I recently replaced the air filters a year early. Manual says 40,000 miles/4 yrs and its only been 3yrs, but Amazon had the Mann filters on sale for $19. Have you cleaned the engine and engine bay? I always under there cleaning everything to check for anything out of place, leaks, cracked hoses etc. What about spark plugs, when was the last time they were done? Maybe remove one or two and see how they look. You mention a misfire, is there a stored code for it?

im just rambling.

 

I just came across the evap diagrams for the M271. Got me thinking have you inspected everything, clean and check all the hoses and fitting. OBD scanner will allow you to run the diagnostics to ensure everything is functioning property. Probably under emissions testing, systems ready? When my purge valve was acting up the engine wasnt running its best, couldnt even start the car without pushing the gas pedal to the floor. I was getting a code for small leak detected.



This is the exact one I bought.

 

Grrrrrrrrr.......

Drove yesterday after completion and had no issues. I'd guess about 25 miles. Today while out running errands I got misfire on 2, 3 and 4. But not enough to not be able to drive. In fact since it was driving fine after and I still had to get home we finished up shopping and there were no more misfires. Probably total of about 35 miles.

Picked up Techron but guess I should wait a bit to add more than half a tank with it. Picked up spark plugs; heading out to look at the old ones and decide of I need t put these in. Air filter comes Tuesday.

And bought a Launch but the lest expensive one for now.

 

I am very concerned that I did not get something back together well. But I would think/hoping that if that were the case misfires would have shown up right away and be more consistent. I am hoping it is more on the side of I fixed something and now it is exposing other issues. Fingers crossed on that, I am not super excited about the possibility have having to pull it all apart again.

I'll try to clean the engine and look at various hoses and connections.

 

The reader will be here this afternoon. I'll review the manual before I get it to have some understanding of how to use it. Is there anything in particular that you think I shoudl be looking at?

 

do you by chance have a vape/smoke machine/ cigarette/cigar? I would try a smoke test on your intake system, that’s a quick way to tell if you have a vacuum/intake side leak.

im with Tim again lol, check spark plugs, ignition coils, any and all connections.. Check for any oil on spark plugs/ignition coils.

I replaced all mine when I bought my c250. I purchased the ignition service kit from FCP. New spark plugs, and coils.

I also recently replaced my in tank fuel pumps and that seemed to smooth out my cars idle and acceleration.

look for any codes/stored codes. If you can get live engine data while the car is running I would note some of the readings.

also, I’ve seen bad battery’s cause quirky electrical issues. How old is your battery?

always happy to help! Keep us posted on what you find with your new scanner.


ant

 

So here is the thing with the reader. I don't know what to look for nor if something is out of range. I am hoping that it will tell me.

 

When you get the Launch download the latest update on it. If its anything like my Foxwell scanner the booklet will not have really any useful info on how to actually use the scanner on the car, just have to turn it on and play around. Then plug it in and run a scan to see which fault codes are showing. Take photos of the screen for later reference.

Keep an eye out for any codes that say active/current. Focus on those first. Try and erase the codes so you will know that if any more codes pop up you know they happened recently. Dont worry about not knowing how to run tests or interpret live data, can figure it out as you go.

 

Good morning. Here is the update, may be good news.

In the last few days: I have added Techron and driven some. I changed the spark plugs. The old ones looked a little black but not bad. I figured it was worth just swapping them all out. I had the battery tested and as a result bought a new one and installed. I installed a new air filter.

Idle this morning when I turned it on (45deg out) was rough. But I drove and it handled well. I even floored it a few times on hills and did not have any performance issues. When I got home the idle was really nice. So maybe it really was just warming up but we’ll keep an eye on it.

Unfortunately, when I got home, I checked for codes and there were misfires on 3 & 4. But I stupidly forgot to clear them yesterday, so I’ll drive again some today and we’ll see of they come back. If they do, I think I need to check/replace coils.

I hooked up the new scanner and took videos of idle before and after driving. Hopefully they are ok but maybe you will see something. Hopefully it all looks good to you. I ran the MB specific diagnostics and did not see anything exciting. There are items there but the were on the line of a TPMS issue, something about a turn signal (which I will need to look at), some audio cable, the GPS antennae, etc…. Good things to know but nothing directly engine related.

I attached the videos below. I hope they are useful. I do have one from before I installed the new battery if you want to see it. But more concerned with the current state of things now.

While warming up -
After driving -

 

Looks good so far. As long as theres no current codes. Im always seeing random codes for non-engine related things that I safely erase and they dont show back up. I had a bunch after replacing the battery. Just take photos of the codes before erasing, keep track if any codes keep showing up.

 

So back to being frustrated. As I said this morning I drove it for about 20 minutes pushing hard up steep hills etc with absolutely no problems. A little while ago I had to run my son to an appointment. Being a bit late I drove somewhat aggressively but not pushing it as hard as this morning. During the drive it felt like it misfired quite a few times. Actually to the point that I was concerned a coil was going to conk out and I would be stuck. Got there and checked; no misfires reported pending or permanent. On the way home, nothing. Drove wonderfully no feeling of misfires at all. I drove less aggressively but about half way home picked it up to try and simulate the same driving as before.

There are no codes and nothing new on the diagnostic scan.

 

All the old spark plugs looked the same, nothing stood out when inspecting them? You dont mention seeing any oil on them so thats a good sign with the valve cover.

When exactly did you feel it misfiring, when accelerating, when stopped, any pattern? I would have assumed any engine misfire would be picked up and recorded and show when running a scan.

Hows the fuel pressure, at idle then when accelerating? Ive never checked while driving but I think my scanner will be able to show while driving around.

 

All the spark plugs looked the same.

I'd say that the 'misfires' all occurred while accelerating but not necessarily hard fast accelerations. For example, accelerating through a turn.

Past experience with this car is that small misfires somehow do not get reported. Then it shows up as pending and if bad enough as a code. I am sure that last part is true of all cars. I have had to change spark plugs and single coils before. So previously I would get the misfires not coding. Then I would take it out and push it hard, floor it going up a hill, and get the misfire to be bad enough to throw a code. Then I would know which cylinder to deal with.

So my wife and son took it for a drive and managed to get a P061B96 The torque calculation of the control unit has malfunctioned. There is an internal component fault. I am going to spend some time on Google tonight.

 

Does that code say Current and/or Stored? Im searching around for what it could be.

Have you looked up your vehicle to make sure theres no open recalls or bulletins on it?

The MB dealer near me has a few service specials and one is for a complementary inspection. I showed it to the SA when i recently brought mine in for service, I just didnt want them charging me for getting it on the lift and telling me what it needs when I already know what the issue is. They seemed to have gone thru the whole car and pointed out a few things i already knew about, they gave estimates for all the work too. If afterwards i didnt want any work done they would have just buttoned the car up and there would be no charge. May be helpful if the dealer near you has an offer like that, just see what they say anyways.

They pointed out my rusted transmission pan, which i have a new one already to install. They also pointed out rusted rear brake lines, which I found funny, wanting to say yea I know and MB should be replacing them for free. I brought up extended warranty work and she at least was aware of the subframe issue, she also mentioned the fuel filter. Ill have to look more into that, I know my car is due for a fuel filter at my mileage.

 

Is this the first time you had that code P061B96? It wasnt there when you first scanned the car and then erased the codes, so its a new issue?

Have you replaced the spark plugs and coils before?

After searching around and not really coming up with much, id say first go back and check all the work you recently did to the car. Check to make sure the air filter housing is on, all hoses connected etc.

 

Sorry, took the evening off, I need a break. So frustrating.

No recalls that I know of. Sadly my MB dealership is almost an hour away. Not a bad idea but not super practical.

That code does seem to be somewhat general in nature. Anything form a a bad ECU to bad sensors to bad fuel pump etc..... Basically anything that could cause it to miscalculate what the torque should be.

I had not seen it before. I am sort of the opinion that I am actually fixing things and with each fix I am causing it to materialize a new issue because performance is improving. Maybe that is stupid though.

I have changed the spark plugs before and two coils that went bad previously.

I am onboard with trying a smoke test but a) unsure exactly which hose to blow smoke into and b) need to rig up some sort of smoke maker since I don't smoke myself.

 

(sigh) I need to stop letting my son and wife drive the car. They took it out and god misfired on 2, 3 and 4. Although 2 did not become a stored code. Below is a link to the report from the reader.

It has has the misfires and the known P061B96. But it also has ESP C221500. I keep seeing this as an issue with the steering angle sensor though so not sure that it applies.

https://usait.x431.com/Home/Report/r...us/timezone/-5

The older ODB2 reader has information right with the cylinder 3 misfire code. I am uncertain that it is a snapshot at the time of the fault or not because it says the vehicle speed is zero. My son says it never misfired while stopped. So not sure if it is from when the misfire occurred or when they stopped to read the codes. It is weird thigh because it is right with the code and I have never seen that before. But just in case here are a bunch of pictures of it all in case something jumps out at you besides it saying the vehicle was not moving. Sorry, they are kind of big, next time I will resize them.

 

Researching and looking through the numbers they don't look too bad though maybe not where I want them ideally. But it was suggested I do a compression test. 1, 2 & 4 - 150psi. 3 - 70psi. I guess leak down next to see if I can tell what the issue is. Not happy at all. 4 also seemed like it needed a few extra cranks to get there than 1 & 2 but it did get there. So will look closer at it too.

Not happy, oh well.

 

Not sure that I am going to keep this thread going but figured I should put some sort of update. I did the leak down 3 came out great and 1 was way off. So I took a step back. I ran the care for a few minutes to warm up a bit and get oil running. Then for the heck of it did both the compression and leak down tests again. All four cylinders passed with flying colors. So great news there.

I did get a bad Camshaft position sensor code. I changed the sensor and it got worse. Read a bit and decided I needed to try a better quality sensor and it improved greatly. Lesson learned there. Still not sure I need OEM but will be more careful with better quality parts especially sensors.

I am still seeing misfires on 3 & 4. Again all new spark plugs and swapped coils 3 & 4 with coils 1 & 2. And still see misfires on 3 & 4. So I don't think that is the issue.

At one point I was concerned abut timing chain (still considering) but when I first turn it on and it sits at 1000 RPM it runs very smoothly. Sounds great no misfires, etc..... it is beautiful. But as it warms up and the RPMs slowly decrease to about 750 RPMs it gets rough and I see misfires. I would assume if timing it woudl never bee smooth. But maybe not.

I notice that when it settles down; long and short term trim are negative bout -5%. I think that is not technically bad but that means rich, right? Fuel Rail pressure stays about 900 PSI. I think that is ok??? Not sure what other live data to look at. Researching.

 

Now thinking maybe fuel injectors but wish I could verify that before spending time and money on that.