03_W203_K

I figured I'd ask the knowledgeable community before I take mine to the shop. This is the deal, I drove my car all day today. When I got home and had to leave again my car wouldn't start. The car sounds like it wants to turn over but after not turning over it just stops. Would anyone happen to know what could possible be the problem. I have an 03 kompressor with 120,000 miles. Only major problem with this car was the alternator. Other then that she's been Great to me.

Please can anyone help. Thanks for your time.

Utahkompressor

Battery I guess!
or Crank-sensor!

Give us more detail.

samaritrey

Battery or alternator. how long ago was the alternator problems? Only reason i say alternator is because if it has already had problems in the past. How old is your battery? could also be the crank sensor easy way to tell is after an hour or so once the engine cools try to start it again or grave a volt meter and watch the volts as you try to start it.

03_W203_K

The only details I have is this:
I started the car at 8:00am, went to run errands and got back home at 11:30 am. The car started fine when I left to go back home. At 1:30pm I was going to leave again. I tried starting the car. It sounds like the car wants to turnover. No clicking, just like a regular start but doesn't. After the car tries at least 6-8 times it just stops.

I last got the alternator changed in 11/2008 and at the time the shop I took it to said the battery was fine. I'm not ruling the battery out as a possibility since its the original from when the car was made. Unfortunately, I have a volt ohm reader and do not know how to use it or to even know what level the battery needs to be at.

Thanks

Utahkompressor

"its the original from when the car was made."

that means 7 years!
...You should get a new one already

03_W203_K

I purchased the car in 2006 and never had the battery replaced so I am unsure if it was before that. I was able to figure out my volt ohm meter reader and its at 12.64 volts.

samaritrey

needs to be load tested. where do you live you could always use mercedes road side assistance.

seagel1000

That's what mines read on the MFC display when i put it on the battery voltage reader feature. This is only on Key position "2" *before cranking the car*

SeaCoupe

Set up the volt meter so that you or someone can read it while you crank. Watch what the voltage drops to.

It is likely you need a new battery. Yes, a load test will be definitive, but the voltage drop has helped me in the past. Anything under10.5 volts is a replacement battery.

Ed

03_W203_K

Okay I set up the volt meter and had someone crank it. The first initial drop was 10.75 and was steady at 11.35

acr2001

If it's been cranking through all these tries without starting then your battery is fine. Probably the CPS.

When you said that it would turn over 6 times and stop - were you using the touch start feature or holding the key? Either way, if it's turning over every time the battery is more than likely fine.

03_W203_K

Cps....Not sure what that is. Can you fill me in. I also tried both ways.

FraKctured

As a rule, I change the battery every 4 years. Cheaper than the alternatives.

samaritrey

cps = crank position sensor
if you go with a mercedes battery i would go 6 years.

acr2001

Don't get me wrong - if your battery is over 5 years old you should at least have it load tested. I just don't think that's what's causing the issue you're having at the moment.

LILBENZ230

From what I gather, the dyno-mode voltage screen is pretty accurate in this. Mine runs down to 10.9v during start-up. 12.4 before start-up. 13.7 after start idle. 14.2 when in motion.

What exactly are the "alternatives" about replacing a battery well before it needs it? These OEM batteries (mine's 5 years old) last a long, long time. If it goes bad, there's always roadside assistance.

ontmiss

Hi everyone! Another newbie here


@ E3 W203 K

Why don't you try with jumper cables? That way you will know for sure if it's battery.

03_W203_K

I took the battery in to get tested and the battery tested fine. I have a mechanic coming by to take a look at it today. I will keep you all posted. THANK YOU ALL!!

SeaCoupe

Yep, the voltage drop says your battery is ok.

When you problem solve, sometimes you go through the easy solutions.

Somewhere on this site is a DIY on the crank position sensor. Not a hard fix, this coming from someone who has never done it....

Ed

03_W203_K

That was going to be my next question. Anyone know of a link to a DIY thread or any image of where this can be possible located?

03_W203_K

Thanks to all that viewed and replied. The problem was the fuel pump. I had to replace the pump, fuel sending unit, and I changed the fuel filter. Once again thanks guys!!

samaritrey

Wow that is interesting. glad your car is fixed.

LILBENZ230

Hi! And no. Sensitive electronics + Jumper cables = Potential for disaster.

BTW a volt meter isn't really needed if you can access dyno mode. This is for diagnostic purposes and is accurate.. IIRC someone on here has confirmed it does load the battery.