Yes, my ML320 has done this since new and while it’s more commonly found on ML’s , 112 engines in other models have exhibited the problem, too. It typically occurs when the ambient conditions are hot and humid and engine temp is between 50C and 70C. Here in Alabama in the summer, with a black truck, it is not uncommon for my engine temperature to already be at 50F-60F after sitting for several hours in the sun.
My problem was so severe that the engine would backfire and stall. It would register a CE light, but it was always just “misfire� codes. I had the ECM reprogrammed and that helped some, but I still get some hesitation on the hottest days and I get really crappy overall MPG in the hot, humid summer months. I have replaced the MAF and the CPS and neither seems to resolve the issue.
There is some speculation that the problem might be related to the runners used for the variable-length intake manifold. The ML’s intake path is a bit longer (for improved torque) than other implementations of the112 engine, so this could explain why this vehicle tends to have the problem more often.
The bottom line is that there seems to be no solution, and MBUSA is fairly tight-lipped about the problem. Most SA’s will officially deny the existence of any widespread reports of the problem, but privately, they know it quite well and often refer to it as “The Miami Problem�. If you ever get yours permanently fixed, please let us know.
In fact I have had this truck for 3 years and never experienced the problem until a few weeks ago. It seems to occur within a mile of my home just after startup.
I did a search of the archives and found many conflicting opinions.
Seattle isn't humid? I thought it rained all the time there! [:)] Seriously, I believe the problem has more to do with humidity and engine temp than ambient temp because even on a drizzly day at 65F, I can have the problem, but on an 85F day with a nice breeze and relatively low (50%) humidity, it’s fine.
The rain stuff is propaganda to try and keep people from moving here. (didn't work) Only rains about 40 inches per year. In the winter and spring mostly. In the summer and fall there is no place nicer in the US. Rarely goes above 80 and low humidity.
My ML has been doing the occasional engine hesitation since new. When it happens, it only occurs in the morning, after it gets warmed up, and come to a full stop. Experience it mostly on the first full stop after getting off the freeway.
I notice the engine RPM goes slightly up and then down, like its down shifting the tran. When the RPM goes down it feel like it wants to stall, but never does.
SA at the time I purchased the ML said, they all do that. Since this was my first MB, I didn't know any better in getting them to fix the issue.
Couple of months ago I took it in to another dealer and SA, they were not able to find anything wrong, no fault code.
I had a loaner 04 ML350, I didn't experience the engine hesitation with it. I wonder if this issue occurs mostly on with the early years? Should we do another poll?
Since we're also talking about Seattle, here's a nice photo of downtown.
I found some good information about the engine hesitation on the early ML models.
I'm going to talk to my SA about this when I get a chance to take my ML in. I will let you all know if this resolves my occasional engine hesitation.
I hope its okay to quote someone else from another forum, Gilly from ShopForum:
http://www.mercedesshop.com/shopforum/showthread.php3?t=97483&highlight=engine+hesitatio n
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Dealer Technical Bulletin 51/00
51/00-2 Groupr 07-All models up to MY (model year) 2000 (except AMG) with ME 2.0 injection system (M112 and M113):
If you receive complaints of rough idle and, or hesitation after cold start, they may be caused by the engine control module (ME-SFI) running very lean after the cold start.
To resolve, please install an updated ME 2.0 engine control module, part number as follows:
(Ok this is an abridged version of the bulletin. It is for the cars with this engine, there is a similar bulletin for the trucks. The dealer should be able to track it down with this info. The part numbers are a bit out of date, I believe they will just need to replace it with the current part number and it'll be fine. For the V6, the newest number, which also is listed as a supercession for the part number given above, is 112 153 22 79, and retails for around a $1000.00. I asked the advisor about warranty for this, he said it would be covered by the Emission Warranty, 8 yr/80,000mi, so maybe you can still get warranty service for it. If you are out of that warranty, probably end up paying for it yourself. There may be some "core value" to the old module, not sure about that though. )
Linear Mode
