2005 CLK 270CDI Auto struggles to start warm/hot

[scarfacetm1984]

Hi guys,hope you can help me with the recent issue.Recently my CLK will struggle to start after let's say little run around,or would say when temp reaches 90c(but that i think not always an issue),so struggles to start or wont start and will cut off when its warm enough.Sometimes depressing the acc pedal helps it to start.
Fuel filter was recently changed but made no difference
So its been off road now for over the month and when its cold its starts first time without a problem.

Any ideas what it can be?
Thanks in advance

 

[scarfacetm1984]

Just a small update.
Been playing with clk today to see if problem shows any more signs.After couple hour of cooling down,tried to start car again,it struggled but after revving it to 2-3k it seemed car wanted to shut down with revs jumping 0,5-1k
if it makes any sense

 

[dazzaf1]

Hi there . I have the same car. I would suggest looking at the high pressure pump at the front top of engine . You will see two clear pipes going into it . They are notorious for cracking. As go brittle. Also. Internal seals on pump leak. Is it wet around that area ?. If it is . You are drawing in air. Once running the metal pump expands thus resealing itself. Took me a while to Sussex but that was my problem. Yours maybe similar. Worth a look mate

 

[scarfacetm1984]

Hi there . I have the same car. I would suggest looking at the high pressure pump at the front top of engine . You will see two clear pipes going into it . They are notorious for cracking. As go brittle. Also. Internal seals on pump leak. Is it wet around that area ?. If it is . You are drawing in air. Once running the metal pump expands thus resealing itself. Took me a while to Sussex but that was my problem. Yours maybe similar. Worth a look mate

Hi,just had a look everything seems fine,will attach a photo so you can compare to yours.Member from other forum suggested its crank sensor

 

[dazzaf1]

Yeah that looks fine. Just thought I'd share my trouble just in case.

 

[scarfacetm1984]

Yeah that looks fine. Just thought I'd share my trouble just in case.

Thanks bud,really appreciate.One thing less to look at.

 

[fingers21]

Crankshaft sensor.

 

[panason1c]

As above, crank sensor needs replacing. (new sensor around £70)

 

[scarfacetm1984]

Crankshaft sensor.

As above, crank sensor needs replacing. (new sensor around £70)

Just tried to start the car from cold,struggled quite abit.Can it still be crank sensor?
Thanks

 

[fingers21]

Yes, a failing crank sensor will eventually cause cold start issues. Cranking for 20 seconds or more before it eventually fires?

 

[scarfacetm1984]

Yes, a failing crank sensor will eventually cause cold start issues. Cranking for 20 seconds or more before it eventually fires?

Yes mate as of today started to play up cold aswell.
the car did 151k,prior to that it did stall on the road once and sometimes struggled to start,so garage changed fuel filter.It helped for the few days but symptoms reaccured again.so off road since then.Though never struggled to start from cold for the last month,just today.

 

[fingers21]

One tip, go for mercedes parts, I thought i'd save a few quid by buying from eurocarparts. Its a pig to change and after I got everything back together, I found the new sensor was faulty. Not a happy chappy!

Could also be a bad seal on the fuel pipe to the filter, they go brittle with age. I replaced all 3 fuel pipes on mine when I changed my fuel filter, but I'd 99% say its the crank sensor.

 

[scarfacetm1984]

One tip, go for mercedes parts, I thought i'd save a few quid by buying from eurocarparts. Its a pig to change and after I got everything back together, I found the new sensor was faulty. Not a happy chappy!

Could also be a bad seal on the fuel pipe to the filter, they go brittle with age. I replaced all 3 fuel pipes on mine when I changed my fuel filter, but I'd 99% say its the crank sensor.

crankshaft sensor you mean bud?

 

[fingers21]

Yeah, crankshaft sensor, sits just above/behind the starter motor. Its one bolt holds it in, but I couldn't get at mine from underneath. I had to remove my inlet manifold to get at mine.

 

[scarfacetm1984]

Yeah, crankshaft sensor, sits just above/behind the starter motor. Its one bolt holds it in, but I couldn't get at mine from underneath. I had to remove my inlet manifold to get at mine.

Just been to see how it starts,which each turn starts better but not as good as before.Also heard a noise which difficult to explain mixture of kind of buzzing with boiling sound(car is cold).

 

[scarfacetm1984]

cant say where it really comes from,doesnt seem expansion tank,somewhere down below.or just getting paranoid

 

[fingers21]

There is a little vacuum pot thing attached to the front of the expansion tank, that tends to make strange noises.

 

[panason1c]

The crank sensor also provides the signal for the rev counter.
On the occasions when the engine won't start look at the rev counter while cranking the engine and the needle should be consistently 'bouncing slightly, if the needle doesnt move that confirms crank sensor faulty.

 

[sjmaxwell]

Just a thought but wouldn't the crankshaft position sensor throw the engine management light on?

 

[panason1c]

Just a thought but wouldn't the crankshaft position sensor throw the engine management light on?

No, apparently not, though it will log a code.