Wont Start - M120 - Benzworld.org - Mercedes-Benz Discussion Forum

**z168** · 01-27-2013, 03:16 PM

Last weekend, I started the car after sitting in the garage for about 2weeks. Started right up, no issues, no hesitations. A couple of days later, it doesnt even do a full turn. So I thought battery. Pulled out my jumper cables and tried to jump (from the trunk not the engine compartment) and nothing. Decided not to pursue jumping further and instead bought a battery charger. Tried the charger's engine start feature - no dice. It only did a very lazy half turn. Decided to do an overnight charge. The next morning the charger indicator said 100%. Still wont start - not even a full turn but a series of what sounds like half turns.

After a little searching, here are the possible culprits according to some threads:

Battery - my battery is only 16 months old. And with the battery charger, it cranks lazily. could it still be my battery?

Fuel filter and pump - Everytime I crank it 2-3 times the smell of gasoline comes out of the muffler - does that rule out filter and pump? I dont step on the gas pedal when I crank it.

Alarm - this thread says arming and disarming the alarm. Did this, no luck

Fuses - checked the fuses in the trunk -all good. Are there fuses I should check in the engine bay? I have a tight garage for the car that I am unable to walk to the front and pop the hood. If I pull the car out to my inclined driveway, I wont be able to bring it back inside. Which explains why I have not popped the hood.

Im used to hear full turns with all other cars. since I hardly drive the 600, I dont even recall how quickly the starter turns. Is the M120 slow to turn?

bomb10177 · 01-27-2013, 03:44 PM

Most definetly sounds like a bad starter. I'm not sure where it is, but I'm guessing its under the engine probably bolted to the tranny. I have never checked where mine is. It could have just had wire come loose either on the ground or on the positive side. Or it could have just gone bad completely.

Also check to see if the engine is flooded. I had moved mine around a few times and then didn't drive it for a few days, and when I tried to start it, the injectors ran, but it didn't have enough juice to turn the engine over, thus flooding the engine.

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**Stryker-1999 S600** · 01-27-2013, 04:19 PM

The batteries for our cars are HUGE in terms of capacity. You may get a read of 100% from your battery charger, but that may be ok for a typical car.

Save yourself the headache and get down to the dealership and buy a proper, MB battery for the car. 16-months on the old battery? Sounds like you bought 'Brand X'.

Starter? Not likely. It turns over 'slowly' or 'half-way'. That's not a starter problem, that's a battery problem. Thank goodness! The battery is cheaper!

**z168** · 01-27-2013, 04:21 PM

this is what I bought 16 months ago

and it carries 805 amps per last reading. After charging to 100% PLUS the charger at "engine start" mode - the engine does 2 full turns and not start. So its probably not the battery

**Stryker-1999 S600** · 01-27-2013, 04:31 PM

Then absolutely go to the dealership and have them replace it. You clearly have a claim on their warranty and it should be replaced at no cost to you.

**merc s500** · 01-27-2013, 04:34 PM

I agree with Stryker here , Batterie isnt charged up inaf .If the engine turns for a little then stops all of a sudden like you describe ,it has to be the batterie .
Take the batterie you have there to a proper Auto electrician so he can measure the amps on it & how good the batterie is ,then you should know from there .
If it is the batterie then you get a new one if not then at least you elimanted her from the fault list .

Zloca944 · 01-28-2013, 01:35 AM

Could be a bad or loosen ground I came across that problem few times on a couple of Porsche's.Check the grounds.

VaevictisAsmadi · 01-28-2013, 02:11 AM

Sounds like a battery problem alright.

My 600 turns a lot faster than other 600s I've driven or watched on youtube. Tis a shame since I cant enjoy the unique sound of 12 cylinders firing in sequence

**z168** · 01-28-2013, 05:46 AM

Did a load test. Battery never dropped below 12V (must be >9V to pass)

Zloca944 · 01-28-2013, 06:26 AM

When you try to start your car when you turn the ignition to start position do you lose or get dim lights on your instrument cluster or you just have starter stop but no dimming the lights.If you have dimmed or complete loss of lights then if the battery is good i bet on the bad or loosen grounds.