Click, but no crank (W211)

[Mohnish]

Hi,

Have seen similar issues posted on the forums,but nothing specific to the W211s, hence this thread:

Turn key in ignition to starter engage position, there is a click but no cranking the engine by the starter. This happens intermittently, may be once in 10 starts or so. When it does start, evrything is fine, no malfunctions etc. Also, the lights do not dim whenever the starter is cranking.

From reading other similar threads, I suspect this to be a weak contact somewhere on the circuit to the starter motor.

Please help. Its an AT so no push starts possible and the thought of switching off and not being able to restart is kinda worrying, especially when the car is parked in a very public area.

Thanks in advance.

 

[ringway]

I had this problem with my VX Omega and it became progressively worse.

Replaced the crank sensor and all was well.

 

[lynall]

Had same on my old TD5 disco and was starter solenoid contacts worn, 1st time i had it repaired cost £25 second time i got the bits and did it myself.
What you really need to know is the signal getting to the starter when it fails to start if so starter duff if no signal fault elsewhere.



Lynall

 

[Mohnish]

I am suspecting this could be a bad / weak contact a the starter terminal. Will have a look at that, clean it and then move further. Also heard a lot about the K40 relay(?). where is this located and its function in this scenario?

Since the fault is intermittent presently, I will never be able to diagnose what exactly is the source, which makes things more difficult.

So, keeping in mind the above, if instead of trial and error, should I wait until there is a definate failure and then identify the cause? In the meanwhile, just clean the contacts along the line.

Opinions please.

 

[Druk]

With a bit of effort you could run a small bulb from the starter energise terminal so at the least you could see if there was current getting that far when it 'clicked'. That would rule out/in the solenoid. (scuse the pun )

 

[jaymanek]

This is typical of a weak battery so its got to be something between the battery and starter.

 

[BlackC55]

Check for broken earth leads otherwise I would suspect a faulty starter.

 

[lynall]

Druks idea ref the wire from the contact to a bulb in the cab then to a suitable earth is a good way to go first of all.



Lynall

 

[Mohnish]

Druks idea ref the wire from the contact to a bulb in the cab then to a suitable earth is a good way to go first of all.Lynall

Yep, am going to try this method first, but again, have to hold in until the problem manifests itself more regularly. However, prior to this will clean the contacts at the starter and the battery earth strap to see if it reccurs.

Many thanks for the advice to all.

 

[Ted]

If the engine earth strap has failed, the test light will illuminate when connected to the BODY of the starter when attempting to crank the engine.

 

[Mohnish]

Update:

Its been some time now, but the strangest thing happened. As stated earlier, the problem was intermittent and hence could not go about diagnosis as it may lead to innaccurate findings, so decided to let it be for the time being.

A couple of months ago, I decided to have the underbody and engine cleaned with a steam/light water spray and generally check the underside, add grease / oil etc. (whats locally called a "service" here in India)

Since that "service" the problem has not recurred!!!

I figure some connector with grime got cleaned? Or do our MBs have a self repair system built in?!!