Hello all. I recently purchased an E-350 4matic sedan and after performing some much needed maintenance on it as it was so badly neglected, I am having the following issue. During normal acceleration the car is doing a few different things: sometimes it shudders between 3rd and 4th gears, other times it surges about 100-300 rpm as you can hear the engine surging and feel it in the seat of your pants. Once getting to the desired speed the motor continues to surge and you can verify it as the tachometer fluctuations match the surge. So far I've changed out spark plugs and coil packs, air filters, and cleaned the mass air flow sensor, performed the transmission reset procedure so it would get rid of the previous owners driving style and relearn my style, ..I've lurked all over these forum posts with no luck. Now under hard acceleration the car performs great but once you reach the desired speed of say 60-70 miles per hour the surging begins. Am taking it in to have the transmission fluid and filter changed out next week.....no check engine lights or any other lights associated with this condition....if the fluid and filter change don't work I'm going to take it in to the shop to have it scanned for codes.....Just wondering if anyone else had this issue and what fixed it? I was thinking something along the lines of maybe a bad throttle position sensor?

 

Vacuum leaks can cause surging, bad MAFs, dirty or bad TBs, misfires, etc... It wouldn't hurt to take off the MAF and boot and check for excessive oil build-up inside. If there is, consider replacement the oil separator as its a fairly common maintenance items on these cars. Without a scan tool, its hard to diagnose as you'd be able to check fuel trims (which could indicate if the running lean or rich), MAF response and misfire counts.

Car was neglected, did the problem exists before you did maintenance? Any of that maintenance could have caused a vacuum leak?

 

Yes, the problem existed before I performed all of the maintenance listed above. I did try cleaning the mass air flow sensor with MAF sensor cleaner and I changed out the oil separator, but I think the only thing the parts guy gave me was the outer cover. After looking at a parts breakdown I realized that there are other parts internal to the oil separator. The outer cover was caked with sludge so I can only imagine what the internals are like. Will get the internals to change out and take to a shop that specializes in Mercedes Benz's and get them to scan it. I also considered changing out the MAF sensor as I have never had much luck with cleaning them.

 

not e350 specific, just EFI cars in general, but surging idle is almost always pinhole air leaks anywhere downstream of the MAF, and/or sticky throttle bodies or idle air controllers (which I believe are the same thing on these m276's).

on every EFI car I've had before this one, any time I've removed the throttle body, I've had to use a new gasket. this includes W124's with m103, m104 engines, volvos with various b230f(t) engines, VWs with whatever 4-banger CIS injected 1.8L my 84 and 89 had, etc etc.

 

p.s. MAF cleaner has never done a thing for me, other than lightening my wallet a little. also, MAF's rarely if ever fail.

 

BMWPower is on the money - use a scantool to look at live data during idle and off-idle (power). That data inclusive of O2 sensor voltage/switching, MAF airflow, short/long fuel trims etc. can help narrow down a direction for diagnosis. Right now you're guessing. A CEL is the "last resort" of the ECM to highlight an issue. You may have an obvious issue like the poor running, but if the powertrain is still operating within preset programmed ranges the CEL will not be commanded on. And yes MAF cleaner can work on a dirty unit as evidenced in before and after scan data of MAF airflow numbers and resulting impact to fuel trims.

If the separator cover was that bad, the internal assembly probably needs replacement. Issue is that if it's not working properly, it won't keep the oil on and only allow oil vapors to be reburned (routed into TB and intake). Oil getting into the TB and intake can turn into coked deposits - in the case of the V6 it can cause the intake internal flaps to eventually jam and break the plastic actuator rod(s) at the front of the intake.

A major factor that I see is that you have a car with unknown and neglected maintenance. A shudder can be tricky to diagnose as it can be a function of engine or transmission issue. Again, a decent scantool can at least help point to a direction to look at. Strongly suggest that if you get a scanner, get one that can look at all of the vehicle modules, not just a basic OBD2 version. They are a bit more, but much more useful over the long run. Or take it to someone that can do this and is familiar with these cars - money spent here for a thorough vehicle inspection and diagnosis can save the time and expense of buying parts hoping they will fix a problem. Plus give you a heads-up on pending troubles. Best is to look for a local indy shop that has a good reputation and knows the german cars.

 

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near as I can tell, the M276 uses a MAP not a MAF, the MAP ("Pressure Sensor") is A0009055906 (replaced A0071530528), and this is stuck on the side of the airpipe after the throttle body.

 

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been driving LH and HFM MAF based cars for 20 years. never had a dirty MAF. never had a MAF fail. put 500K+ miles on one volvo LH2.2, 200K on another LH 2.4, owned a couple more for shorter periods.. only way a MAF would get dirty is if you had a air filter completely disintegrate (rodents?), OR if you used those nasty oil soaked K&N things. Or, I suppose, if you had an engine that was doing some nasty backfiring. I knew a guy who ruined a Bosch/Volvo LH MAF by over cleaning it, but I think he let the spray run down the wires and into the electronics pod on the side. I think I said above, hold them so thats on the TOP and the air path is horizontal but slanted down on one end, and spray from the uphill end. The LH MAF's I'm most familiar with had a hot wire ("Luftmasse-Hitzdraht" == air mass heating wire), while the later W124 M104 engines used a HFM hot metal film version. 10 years of ownership of two HFM based cars, plus extensive participation on benzworld in the w124 forum acting as a resident electrical guru (my forte) and I don't think I ever heard of a single HFM MAF failing. When the Volvo LH MAF's failed, it was usually due to the electronics having gotten zapped by stupid human tricks like hot plugging them while the engine is running.

but anyways, the M276 engine in most of our 212 V6s and I presume the M278 V8 equivalent, they don't have any MAF, just a pressure sensor, which is an alternate way of doing it.... pressure sensor based injection systems typically need a throttle body position sensor, but if its drive-by-wire like these cars, thats baked in. I've also not heard of many of those MAP sensors failing on the older euro cars I've been around, but they are certainly cheap enough. I did have to replace a MAP on my son's old Tiico Audi-I4-converted Vanagon Westfalia, but that was because I upgraded the original Tiico ECU and the original MAP didn't have an embedded temp sensor that the new ECU wanted. of course, this meant replacing the harness connector for the MAP and running an extra wire to the ECU.... when I was done, that Vanagon ran like it had never run before, then a couple months later, his dippy GF ran the oil dry and seized the motor, ARRRRGH. yeah, he knew the oil pressure light wasn't working, I told him to fix it, but did he listen to Dad? naaaaaah.

 

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yeah, I bought one of those WIS/EPC DVD sets, and its *AWFUL*. the FSM (Factory Service Manual) for the old 124 vintage cars was so much easier to use, as was its wiring diagrams. the wiring diagrams in WIS for newer cars are really really hard to read.

for parts lookup I'm pretty competent with the Parts Information system that I'm paying $75/year for access to (hey, when you own 4 Mercedes, why not?), but again, the stuff on that WIS/EPC is awful, I can't find anything.

say, does your WIS virtualbox pirate edition WIS crash a lot? mine locks up if I look at it sideways, and I have used the same VirtualBox to run all sorts of other VMs without a single hiccup for years. Now, I imported their vbox/vdi files into my existing VirtualBox 6.1.12 r139181 install rather than running whatever funky oldder vbox the disks had on them, and I did update the VirtualBox Extensions of their Win7 Pirate Edition VM to be compatible, so screen sizing works.

 

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VirtualBox IS a VM. So maybe you're crashing/locking up because you're CPU is pissed off that you're trying to run a VM inside a VM inside your host OS lol

 

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hmm? no, I'm running VirtualBox on my real Win10 desktop computer and its running the WIS VM. same as any of my other VMs (I have an old XP VM thats running without any networking, and has a bunch of old Volvo stuff on it, I have to set the date back in that VM to like 2013 or some of it refuses to run. same VM also had a BMW thing on it thats a full parts catalog for any cars or motorcycles up to around 2003, it covered my 1996 R1100RS.

hah! the things we do.

 

Maybe a corrupt .vdi?

 

well, it came as a 7zip and afaik that has decent error detection.

 

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Time to give you all an update....the surging problem has been resolved...It was the torque converter kicking in and out....so a transmission rebuild kit, torque converter, fresh fluid, and a new filter and it's driving like new. Cost me $2700.00 and has a 3 year warranty on the work performed.

 

When you say torque convertor kicking in and out... do know if that was due to the lockup clutch? So the torque convertor was replaced and the transmission rebuild, correct?

 

I had a similar diagnosis from my indie today for a similar issue, but they quoted me $3-4k CAD for the work, depending if I need just a TC or a full rebuild. He mentioned that once the work is done the trans needs a software update of some sort, is that right? i am wondering if I can take the car to a cheap mechanic and have them do the work for half the hourly rate that his guy is charging.

 

For just a TC replacement, at minimum they should update the adaptations in the TCU and reset TC lockup service life. Full rebuild, if that includes a new conductor plate SCN and adaptations.