Starting problem

[C23o silver]

If its the same as the Op's your issues come when trying to start the car hot, right? I'm not SURE its that- but its something I have experienced before - car stalling and EML coming on too- replaced the CPS and off I went! (This was in a C180 a number of years ago!)
One of the indies on here will likely pick up this thread and have other ideas possibly but that's my twopence worth...

Thanks alot John,if I could maybe explain what happens, the car will kind of smother,like not getting fuel,battery /alternator warning will come on,I'd put in like 2 litres of fuel and it would start right up,last week though,no matter what I did,it just would not start.

 

[LostKiwi]

Yes CPS is crank position sensor.

 

[C23o silver]

Yes CPS is crank position sensor.

Hi lost kiwi,thanks for confirming,

 

[turbopete]

the issue is usually the heat soak into the CPS so short trips up to temp aren't too much of an issue, but long trips or a hot trip, park (heat soak ) then non start. they can be tested with a multimeter and they go open circuit (on resistance scale) when hot if theyre shot. as a rule around 800-1200 ohms is about the norm for a heated CPS (I used to test mine with everything but the connector inserted in boiling water for 10 mins, then measure resistance across the connection 'pins')

 

[John Laidlaw]

Thanks alot John,if I could maybe explain what happens, the car will kind of smother,like not getting fuel,battery /alternator warning will come on,I'd put in like 2 litres of fuel and it would start right up,last week though,no matter what I did,it just would not start.

Yeah almost certain CPS and yes that's the Crank Position Sensor- as others have said its a relatively cheap fix/replacement

 

[C23o silver]

Yeah almost certain CPS and yes that's the Crank Position Sensor- as others have said its a relatively cheap fix/replacement

Hi John, will test and let you guys know by tomorrow. Thanks again for your patience and assistance, trully appreciate it.

 

[John Laidlaw]

Our pleasure, hope you get it sorted, I feel your frustrations

 

[Steve@Avantgarde]

Well, I dont think it is a crank sensor fault....and no diagnosis has been done, so its a frivolous guess at best.

Firstly, the op has a 230K engine, neither 111's or 271 engines suffer from CPS issues like the V engines. They use a different type of sensor, and using STAR, you should be able to test the CPS in any case as well as it leaving a fault code behind as its a pulse inductive sensor.

So lets start from the top (and preferably on another thread to make life easier) what are actually the symptoms of your fault? When does it happen? When does it start back up? Do you have any fault codes?

 

[C23o silver]

Good evening Steve,thanks for your interest and reply,my car only does the no start problem when the tank is at 1/4 tank or less, it will stall and when restarting the engine, it sounds like a car smothering as though not getting petrol,the battery / alternator light will come on,on Friday evening, I sat for a while until the temperature went down a bit and the battery / alternator light was no longer coming on. There is no diagnostic pointing to anything as yet. There is fuel in the rail, the car starts,drives and everything, until a certain time,cannot confirm if it is at a certain temp or not.

 

[C23o silver]

On addition to the reply to Steve,although not confirming anything, my last trip to the auto electrician, he checked faults, non relating to what was happening, but reset all fault codes,and car ran past where it normally did,until I threw in fuel,went up to half tank and for the first time it did the no start between 1/4 and half,and after throwing in more fuel as usual, it just refused to start. Car was towed to Mercedes and left for the weekend, and when they checked the car,it started right up.

 

[Steve@Avantgarde]

How do you know there is fuel in the rail, have you done a fuel pressure test when the fault occurs?

I think you need to move away from the computer based diagnostics and move to more basic diagnosis. When the fault happens I think you need to measure its fuel pressure.

W203 C Classes have a know issue with the fuel pump and sender units.

 

[C23o silver]

That's the problem Steve, the car was with Merc for a week, they never drove the car until it stalls,a test was done when it wouldn't start previously, and there was fuel in the rail, no pressure test was done ,

 

[C23o silver]

Good evening gents,hope all is well in the land of Benz,quick update as to my dilemma, car stalled again today and the only code kicked out is a P2036-001 Secondary air injection: malfunction (function chain), Airflow is too low(P0410). Anyway, any ideas,of some sort,would be appreciated. Keep well guys and ladies, your friend in Benz

 

[LostKiwi]

Good evening gents,hope all is well in the land of Benz,quick update as to my dilemma, car stalled again today and the only code kicked out is a P2036-001 Secondary air injection: malfunction (function chain), Airflow is too low(P0410). Anyway, any ideas,of some sort,would be appreciated. Keep well guys and ladies, your friend in Benz