mwillems

When I start my ML320 Bluetec in Canadian cold, say this morning's -12C, the first few minutes are very, very rough - initially I get only a few cylinders firing, it kicks back, etc; then it moves but roughly, and eventually when it warms up it's fine.

Are those super-rough cold starts normal?

Michael

Paul S8 ML350

I don't know about a ML diesel engine, but that's very normal for any type of diesel to run on a few cylinders when very cold until all fire.

roadrutz

From an engineering perspective there is no reason why, if one cylinder is firing in a common-rail diesel engine, conditions shouldn't be right for all to fire. I have a motorhome with a 6.8 Cummins diesel; I don't run it when the temperature is as low as -12C, but I frequently run it at temps down to about -5. It always starts fine and runs on all cylinders right away. Lots of black smoke, yes, but that is because you have aluminum pistons in an iron block -- as soon as the engine warms a little and the pistons expand, the smoke stops.

jsmith18

I live in Calgary and my 320CDI is not very rough at all at -10C, I leave it out all the time at -25, but plugged in, and its not very rough then either. Until it warms up it is a little slow, ie. not much power and I just baby it until it warms up. It should idle a little faster for a short while at that temperature.

Vernl

It depends on the individual computer programming for extreme cold starts. Since diesel only fires when its hot the computer will run engine as required for a few seconds or even minutes until it senses its warm enough to fire the injectors to a given cylinder. I have started diesels in -40 temps and they sound like they are barely running. As long as you wait till your glow plug light goes out then your start will be as smooth and as short of cranking time as possible. if you want to make things a bit easier . you can plug in the block heater.

mwillems

But this is worse - initially, it kicks back at me and clearly fires on only a few cylinders. Sounds and feels like it'll tear itself apart.. not fun. Only lasts a few seconds, but still!

Don't (as far as I know!) have a block heater.. probably should....

tom_g

I'm considering an ML320 CDI and currently drive a VW Golf TDI. In the Golf I need to wait for the glow plugs to heat up (turn key part way, wait for the glow plug light to turn off) and it starts fine. Without heating the glow plugs, the engine will start extremely rough from even 3 or 4 below. Should only take a few seconds in -12 for glow plugs to warm up. Not sure if relevant to the ML.

Vernl

I believe all Canadian models have block heaters

eaadams

good post!

As somone who live somewhere where we use Diesel #2 do you still have to use Diesel #1 when in freezing / snow conditions?

dgiturbo

I have never had a rough start in my CDI since new. When it's -20F, I turn on the ignition, the coil light illuminates for about 1-2 seconds, then I start. It does crank a little slower, (cold battery) but fires right up. Idle goes to about 1100 RPMs, and for the first 5 minutes of driving, it will feel as if I am pulling a heavy trailer as it tries to warm itself (and me) up. Never a rough start though. Get that checked. Might need a computer software update?

I did have it NOT start once when it was -25F and the diesel fuel gelled. Now I use an additive, and no more gel issues. Could you have water contamination in your fuel?


I think if these engines misfire in any way, the computer will through codes and the CEL will be on.

On a second note, the US models do not have a block heater, so I envy you Northerners.

jsmith18

My ML CDI in Calgary always starts like yours dgiturbo. Interesting that you use a diesel additive to prevent gelling. In Calgary we have a winter diesel, but I am leaving fom Palm Desert CA on Friday to drive to Calgary and just purchased Power Service diesel supplement to add to the tank in case I have to drive into the cold weather with #2 diesel. Have you had any issues with the particulate filter?

mwillems

So my dealer manager denies there could be any misfiring.

Misfiring? When cold the engine nearly blows itself up, that's how bad it is for the first 10-20s!

What can I do when the dealer manager refuses to believe me? Yes I do know about engines, being an engineer and having taken my motorcycle apart often enough when I was young...

mwillems

...but I willhave the dealer check the fault memories. And water - possible but unlikely. And block heater? Do I have one? Oh?

Vernl

Perhaps have someone capture it on video c/w audio as you start it and show your dealer..he can then decide if its out of the realm of ''normal''

mwillems

Good idea.. except now it's plus 10 Celsius instead of minus 10!

Messerchmidt

use some powersource and amsoil diesel fuel additive, will correct the problem

you add it on an empty tank right before you fill up (so the fuel filling the tank will mix it around). The car runs smoother, with less smoke, and starts easier.

dgiturbo

You may have a bad fuel injector(s) that shows up in extreme cold? Keep us posted. Might be worth parking overnight at the dealer so the problem is reproduced when they start it up.

Jsmith18, we do have winter diesel here as well, but after that one time in January when it gelled for the first time, I am now using the additives. Been driving a diesel since 04, this car since 07. Never had a gell/freeze up issue in winter before.
I have never had a particulate filter issue. Hope I never have one. The additive I use is for ULSD cars.

Brocktoon

This is not right, I started mine at -23 in Calgary yesterday and there was no roughness at all. Your service advisor is on crack. Just document your cold starts on your camcorder, and post it on youtube, send crackhead a link, then see what he says.

clearwaters88

Anybody know if the US Vehicles are equipped with a block heater? we have purchased a ML in the states and brought it back to Canada, no idea if it has a block heater and god knows we need it up in Edmonton! If it does have one where can I just purchase the cord?
Thanks
Shalil

sheepdog8

Quick note ref. VW Tdi's. I bought my wife a 2013 Jetta Tdi. It's glow plugs have Zero warm up, fires instantly, vs my ML320 which when cold takes 1-2seconds for the glowplugs to warm up & the light to go off. Her VW doesn't even have s glow plug light on the dash. I assume it just has a newer generation of glow plugs???