Update: this blog post will not be updated further. The topic needs its own page, including an issue history and log. See:
... original post, not updated follows below...
Today’s problem‚ something new or just a symptom?
Today, my 2017 Mercedes Sprinter would start, but then lugs badly at 2 seconds at 500 rpm, then quit. Plenty of cranking amps no question. Repeated failures.
Temperature overnight hit maybe as low as 15°F at 1000' elevation, but Sprinter console showed 19°F at 8AM when failures occurred. Tried 3 or 4 times, then gave up and went for a hike. At 3PM it started up fine at 37°F. Ran fine once started in the afternoon, but I did let it idle 30 minutes to be safe before trying to move, because of ongoing issues detailed below.
OK, just for giggles, one might blame it on fuel but that seems unlikely—not really cold enough and no other issues noted on same tank of fuel for a week. Even though not winter blend fuel (AFAIK), it just did not get cold enough.
Today’s failure is actually not my main concern, as it may only be a symptom of the more insidious and ongoing issue, which is getting worse and worse, plaguing me before and after Service B (so not the fuel filter) for around a YEAR. So it's not a particular tank of fuel or a fuel filter or a particular temperature.
SYNOPSIS: normal idle, put into D or R, Sprinter goes nowhere, rpms drop and engine lugs
Having mentioned this problem to more than one service department on service visits, and getting little more than shrugs, my hopes are not high for seeing this resolved. I want a dealer to call Tech Service and track this down! I have one dealer in mind who might get the job done. My confidence in another is near zero.
Maybe all it is is software, but the truth is that mechanics hate doing them—my information is that Mercedes pays them very poorly for piecework that can take hours yet pays only for 30 minutes or so (not paid by hour). So one never knows if all software is up to date or not and it can be like pulling teeth to get the latest software.
Contact Lloyd with ideas or similar issues.
- Start engine, give it half a minute or so to warm up. Observe rpms at 900 to 1300, depending on altitude and temperature.
- Put into D or R (doesn’t matter).
- PROBLEM: observe rpms drop to 500-600, engine lugs badly (audibly bad).
- Floor accelerator pedal: absolutely nothing happens, even for minutes.
- Put back into P: rpms return to normal. Rev engine—revs up to any rpm freely
- Repeat ad nauseum. After some indeterminate period (2 to 10 minutes), the problem may resolve with the Sprinter reluctantly moving away. However, if there is any up-slope, it may have trouble for another minute or so.
Part 1, after idling 2 minutes to warm up:
Part 2, after idling 9 minutes to warm-up:
- Might be altitude related, but this is not certain; I don’t start my Sprinter at home much, but it has not failed at home (500 feet altitude). Failures seen at 6000/9000/10000/112660 feet elevation.
- Goes into gear; does not appear to be transmission related—just makes no power
- Seen at least a dozen times over a year from 6000 to 11600 feet
- Happens over a wide temperature range, at least 14°F to 54°F, so if temperature related, does not have to be more than just cool temperatures.
- Intermittent problems so hard to diagnose.
- Full service B done in April 2019, problem occurs before and after a year, maybe more.
- Lack of turbo boost due to faulty altitude or other sensor(s)?
- Faulty ECU software? No problems seen prior to Feb 2018 ECU software update
Updates / log
2019-10-01: 9000’ elevation, 25°F @ 10PM dipping to 9°F overnight, started up fine @ 8:30AM @ 27°F idling @ 1300 rpm slightly rough idle, just let it warm up, and once warmed, it would roll in reverse without issue.
2019-09-30: 8100’ elevation, 27°F @ 10PM dipping to 20°F overnight, started up fine @ 8AM @ 28°F idling @ 1300 rpm slightly rough idle, died when tried to move with parking brake slightly applied on level ground after one minute of warmup. After two minutes warmup, was able to reverse on level ground (no brake), rolled away in D on level to downhill, engine steadily warmed up and behaved normally.
2019-09-29: stranded most of day as per full description.
2019-09-28: Sprinter would not go as per detailed description
2019/2018 year prior: perhaps a dozen such “no go” problems, ranging from a minute to 10 minutes in delay. All at altitude of 6000 feet or higher as far as I can remember.
I have exactly the same experience.
First, I know my science is sub par to your excellent work but my ramblings may shed some light on it.
1) Because you like science I suggest the most knowledgeable MB dealer on “ cold” is Lone Star MB in Calgary,AB. Before calling them check their website blog - not sure if it has this item but it may be & they do have some useful info I have read.
2) My prior Diesel + Cold experience was with a Ford Excursion 6.0 Diesel. That puppy was dead at 20F & no amount of glow plug action could start it. Only spraying Ether in the Breather would work but I hate that stuff because strips the oil off the piston rings. The SOP was to wait until temps got above 25F & it would start reluctantly (assuming one had not totally depleted the 2 batteries during the failed Glow plug attempts)
3) In my experience the Sprinter will fairly well start above 20F but run rough. As the the temperature drops below 20F it requires successive Glow Plug cycles (without actually engaging the starter!) At 18F I found that it would require at lest 6-8 cycles. And it would start & stumble & cough etc etc, always die on the first full start attempt and then require 2 or 3 of the prior procedures to finally get it to run (very very rough & not quit).
Now for the next hurdle: assuming you got the engine running for awhile, at least to the point it “sounds “ normal (maybe 15 minutes) the Sprinter acts like its stuck to the ground. Without any authority I am fairly certain it’s due to the fact the transmission is still 15F & the fluid like glue. Since there are no shared fluids with the engine you are relying on plain old heat transfer from the adjacent engine block which might take 20 minutes of engine running to get the transmission to respond (& even at that, sluggishly).
4). The solution: install an Espar Hydronic Diesel water heater to solely to pre-heat the engine to 180F 🤪. Engine starts like its in Miami & the Tranny goes along for the ride. Then it never matters how cold it is ! (Bonus it saves all that ritual unassisted cold weather starting procedure which has to be hard on the engine.
DIGLLOYD: I never had these problems the first six months of operation. But after the Feb 2018 ECU update required by the California Air Resources Board (with sticker required to smog check), things seemed to not run so well. So I am dubious that it is a 'hardware' issue. And if it runs rough at start, it has always settled down pretty quickly in the past.
Moreover the Sprinter hardly ever pauses for glow plug operation... I didn’t even know it really had them! It had no pause whatsoever trying to start it today. Which raises the question as to whether they are working at all?
I’ve had the Sprinter start many times in sub-freezing conditions and run normally. But the sub-25°F experience is more limited. Last December I had it exhibit the symptoms going to bed at 25°F (engine still warm) but a warm front had moved in and it was 43°F when I started it, and had been for some hours from what I could tell. And I’ve had the no-go issue into the high 40°F range (and did not keep track all this time) I think also the low 50°F range. So I don’t think the no-go issue is heating issue. The does-not-start-and-stay-on issue today is all new, and definitely not the coldest temps I’ve been in it with—and I had gone to bed with a nice warm engine.
Still, the Espar Hydronic Diesel water heater might be worthwhile, but I admit to it being intimidating on who to have install it and inspire confidence that it won’t spring a leak or cause issues of its own.
Mark G writes:
Dang. Sorry to hear that. I have almost given up on the Mercedes Sprinter. Backed out of custom order at the last minute. Now waiting to test drive a 2020 Transit AWD with ecoboost (most powerful) gas engine. Planning on some custom suspension mods to improve ground clearance if I decide AWD is good enough for my needs.
I want a Sprinter for many specific strengths but diesel engine and all its related concerns are just too much to ignore. There's a good sprintersource post about block heaters and this issue you describe somewhere on the forum. They found a specific issue that was something related to the turbo, or some other part that a certain dealership had identified. They had an overnight test they could do in the dead of winter to diagnose. MB was made aware. That's all I remember. Let me know if you find a solution.
Hang in there sir!
DIGLLOYD: I guess one half-assed solution is to drive around and make the engine hot before going to bed, then wake up at 2 AM and (bad for a Sprinter) idle it for 20 minutes, then pray for morning.
The question of the turbo is a good one—my guess is a software bug and/or altitude sensor bug that causes the turbo to provide no boost. After all, how many people regularly camp out at 10K feet or (often) 11600 feet? Tonight I am at 8100' and I will see how it behaves in the morning. I parked where I have a cell signal and sunlight will hit early and it's flat, just in case!