last yr cold stalling usually at incline or turning off ramp ,usually at minus 10 to 20 degree celsius
rest in underground heated car park.starts again
changed voltage regualtor,same thing
changed back from plat to copper though resistance plugs ,same thing
finally last yr mechanic over the phone diagnosis,change battery,went thru last yr without further stalling.This yr got new battery again one month ago as prophylaxis just in case.so battery Interstate 91 HD only 1 month old.

This yr 1st cold snap,yesterday and today minus 20 celsius,ie minus 4 fahrenheit, or 4 below F.stalled again,jumpstarted sputtered and started.
Added gas line antifreeze to already almost full tank.

checked battery,12.35 with ignition off and alarm on only.Idling,13.8 -9 V,1500 rev 14.0 or 14.1 V. With batt disconnected tonite after driving home and charging battery by alternator only ie by driving home,12.77 V (disconnected from car)

I am thinking of changing the plugs to mercedes non reistance plugs,other than that,are there anything that one may suspects,Are there any grounding points for the alternator that is easy to reach in cold weather.The groudning point for the battery negative terminal seem s okay.


bad contacts when cold,bad contacts at ecu???????Dist rotor and Bosch wires only few yrs old.

Thanks for any advice

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Tom 2010 C250 4-matic Sport (Canada)

p.s.when i lived in Manitoba cold country,used to attach cardboard to grille of car to keep car warmer,
should i do the same with the MB,but may be unsightly for such a "status "car!!!!!!!!!
anyone in Minnesota,North Dakota or Manitoba,Sasketchewan or Edmonton doing same?

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Tom 2010 C250 4-matic Sport (Canada)

I never heard of a battery or alternator causing an engine to stall Look somewhere else.
Have you replaced your fuel filter?.
How's your cold start injector?
Have you checked fuel pressure?
How's your idle control valve?
Any vaccum leak?
Get back to real MB plugs.
You saidist rotor and Bosch wires only few yrs old
......don't assume they are perfect. Check/test them.

idle control valve was checked by mechanic,okay
fuel filter few yrs old.

The funny thing is it always started by jumpstarting from another car.
What can cause this??????


It seems to me jump starting only good to take place of non functioning battery,charging system.If the fuel pressure/fuel filter is no good,how can jump starting start the car????

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Tom 2010 C250 4-matic Sport (Canada)

I am no mechanic but
2 facts may hold clues
:
(1) always restarts with jump starting (despite battery and alternator both seems okay later).
(2) only happens at minus 10 to 20 celsius(4 degree below F)NOT when weather is warmer.

Thank you for your responses

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Tom 2010 C250 4-matic Sport (Canada)

I would have the amp output of the alternator measured and the battery voltage measured while car is running in very cold conditions. you said they seem ok but you have to take some readings I think.

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2005 Mercedes C230k sport sedan, 6 speed
1987 Porsche 924S - 968-engined track car

Thank you Schumi,for your response.

These 2 days,milder clime so only 23-41 F(-5 to + 5 C).so no problem with car.Bought Bosch copper non resistance plugs,not yet installed.Changed fuel filter as it was 3-4 years old,but I did not think that was the problem as the car only had problem in -20C ,and same problem 12 months ago.

I checked the not covered ?negative terminal of the alternator and was able to tighten the nut 3/4 turn so I loosened again but squirted some WD40 to get rid of any moisture which may turn to ice in -20C.Retightened and sprained blindly back of alternator down below too.the terminal is not corroded.See picture below if attachment successful.

Checked alternator voltage again after tightening that nut.14.3 V,ie 0.2 V higher than before nut was tightened.So I surmise that the loose ground may be responsible for some loss of electrical contact.or if colder may have virtually isolated the alternator with ice in between?????

Anyway,took it to Sam's Club to get free charging system tested.
Battery 91 HD Interstate rated 700 CCA,1.5 month new,at rest 12.97V,787 CCA
Starter test 11.57V 1.24 S
Charging system test
14.3V no load
14.21V loads

Tech advised everything okay.

Will wait and see if problem returns.
Have a merry X'mas and Happy New year,everyone.
At least it's warmer these few days.

Attached Thumbnails

 

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Tom 2010 C250 4-matic Sport (Canada)

So far so good.
Temp never more than minus 10 C except overnight.

Expenses so far :
tightened ground terminal free+card board covering grille(yes,I am a former manitoban,free almost)
fuel filter replacement at dealer 's "quicklube" place
plugs

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Tom 2010 C250 4-matic Sport (Canada)