203 Not Turning over

[rjevon]

Think I have managed to gain enough access to replace the ignition switch..

My final question before I do it is, do I need to disconnect the battery first ?

Richard

 

[Cole@MBS]

I never do Richard.........

 

[rjevon]

Managed to get the plug off the switch but cannot get the switch out..

Plastic clips either side, just like the plug, but can I get to the clip thats not visible !!!???

NOPE..

My hands are probably too large for this type of work..

 

[Cole@MBS]

Its a fiddle to do, i use a little hook tool to press that one in......

 

[rjevon]

My hands are now in tatters, but DONE..

Will take for a drive and see what happens when I get back !!??

Thanks again.

Richard

 

[rjevon]

Bugger !!!

Not the ignition switch then..

Took it for a drive and came back home. Turned engine off and tried to start it straight away and Nothing, juest the usual dash lights...

But, after about 5-10 mins when trying to start it without waiting for the glow plug light to go out, you can here the Starter Motor kick in for a very small amount.

The longer I leave it before trying again the longer the stater motor turns, but at most half a turn.

Sounds like something is restricting voltage, resistance somewhere when hot and gets better when cooler..

Any ideas, does this sound like the Earth Strap (which I will be getting a proper look at tomorrow) ?

Or a sticking / duff starter motor ?

Thoughts, any greatfuly received :-(

But thanks for all your help so far.

Richard

 

[cleverdicky]

dodgy solenoid ?

 

[Cole@MBS]

You need to check that earth strap Rich..........

 

[rjevon]

Earth strap being checked properly tomorrow.

Additional info, that was at the begining of my post in here, was I fitted a new Battery.

The original one was a much smaller one than the recommended one which I have replaced it with.

Think the one I have in it now is the 019 ? 110Ah with 820 ish cranking amps, and the last one was a Merc one of 70Ah 450Adin 760Aen with a part number of 570 901 076.

The new one is alot larger and is very tight in the battery compartment as it is longer.

Could I have caused any issues with a cable at the bulkhead end if pushed to far up there ?

Richard

 

[Mercedes-2010]

Very common fault with the above model, petrol and derv, more common on the 200-220 CDI.
Turn the key, full dash lights but won’t crank over!
Remove the off side splash cover above the fuse box lid, un-clip the cover for the fuse box! You’re now looking at the front SAM, to the left bottom on the picture; you can see the yellow 20amp fuse, number 54! Check this is a 20 and not the standard 15 the car was fitted with!

If the fuse is blown, un-clip the circled plug, purple wire is a straight feed to the starter trigger! Disconnect this plug and replace the fuse, now turn the key and check that the fuse hasn’t blown again, if the fuse is ok then there a good chance that the starter is causing the short in the circuit!
Taking power from the jump starting point on the other side, under the red flap in the picture,

and try to flash the starter up using the 12 volt from the jump point! There’s a good chance you will be met with a heavy flash as you try this! That pretty much confirms that a new starter is needed,
If you really want to go a bit further, you can get your hand down the n/s of the engine and disconnect the 10mm trigger lead from the starter! Make sure it doesn’t touch any metal! Turn key again to confirm fuse doesn’t blow!!

Just looked at my schematic to see if mine's a 20 amp or not, fuse 54 in the top picture is a 7.5 amp! Do you mean 52? Just checked and upgraded mine to a 20 amp.... Cheers for the info..

Please correct me if I'm wrong...

Cheers Dave

 

[three poynted star]

Do same as me put a meter or even bulb on two lenghts of wire.One to earth one to purple wire which goes to starter turn ignition to start position see if you have power to it if so i would do the same as me and change starter motor.Try it a few times though just to double check.

 

[rjevon]

Getting it all checked this afternoon.

I take it that yours was sorted with a new starter motor then ?

Gettin the Earth Strap looked at first, from advice from this super forum.

Fingers crossed I dont need a new starter as they are a little bit more expensive £££

Richard

 

[Alex Crow]

Easy test for the earth strap - measure voltage between engine and battery earth terminal when attempting to crank.

If it measures up to 0.5V, well OK, but if it spikes to 9v you know what to change!

 

[rjevon]

Right..

Took it to our local garage.

Looked under the car and could only see one earth strap, a short one between chassis and engine..

Is this the right one we should be looking at?

Anyway, it looked perfectly fine, not corrosion or anything and secure at either end.

Could not get car to fail, as when I arrived the ramp was not free for approx 30 minutes. So the car was left idling for that time, so when we switched the car off it started again without a problem. Grrrrrrrrrr :-(

Got home and straight away it fails.

Again if I turn the key to starting position without waiting for the glow plug light, the starter does kick in for a split second or so... almost as if it had just enough stored voltage just to do that but not crank correctly.

If I wait for the glow light to go out, it does nothing.


The longer I leave it, like the last five / six minutes, the more the starter turns over !!, almost as if the battery is on its way out and takes time to get enough votage to start the engine !!?? wierd.

The garage did say it may be the auto starting relay??? The relay that allows you to just turn key to starting position but release straight away and the starter motor continues until engine has started ???

Will have to book it in with a proper indie I think.

Not sure what else to do..

Richard

 

[three poynted star]

If you take it to an auto electrician he/she will have the eqiupment to check the draw when your cranking it over etc he will know by the amps its drawing if its the starter a normal car garage only do limited checks on things like this. strange how it all started when you changed battery ?

 

[rjevon]

When I say it started when I changed the battery, that is on reflection a little missleading..

I changed the battery at the same time the cars usage changed. My wife would go to uni or work and come out after uni or work and start car nomally without any probklems.

But with the hols etc, my wife is doing short drop offs that I would have done, so school run - turn car off and bam it would not start..

So the battery is prob not an issue, it may well have done the same thing with the old battery, but we will never know..

Richard

 

[Mercedes-2010]

If this car is an auto which I assume that it is, what about the inhibitor circuit for the gearbox?

The thing that will only let the car start in N or P...

I used to use this circuit to immobilise my vehicles many years ago...

DC

 

[rjevon]

Local indie are sure that the Starter Motor is at fault.

Fingers crossed...

One more question... I have read in another post that there is some wireing that goes through the Inlet Manifold to the Starter Motor...

I had my Inlet Manifold replaced with a modified one, could anything have been done that could have effected it with regard to heat issues on starting ?

Could a cable have been placed to close to the engine that makes the Starter Motor work ?

Thoughts ??

Richard

 

[Mercedes-2010]

Local indie are sure that the Starter Motor is at fault.

Fingers crossed...

One more question... I have read in another post that there is some wireing that goes through the Inlet Manifold to the Starter Motor...

I had my Inlet Manifold replaced with a modified one, could anything have been done that could have effected it with regard to heat issues on starting ?

Could a cable have been placed to close to the engine that makes the Starter Motor work ?

Thoughts ??

Richard

Very likely, it does seem a wee bit silly for Merc to engineer a harness / loom to go over a HOT engine and even the best mechanic couldn't avoid damaging a wire within a loom when moving it aside to replace a manifold...

Let us know the outcome!

I'm still convinced on the starter inhibitor circuit may be an issue!

DC

 

[rjevon]

UPDATE !!!! Grrrrr

Took car to an Auto Electrician who said it was the Solenoid.. replaced it and the problem is still there.

Called the AA out, great guy who spent a lot of time on the car.

Replicated the problem, Dash lights on but no cranking and the occasional click of the solenoid etc..

He located a bad earth which was showing about 3.4 volts.. this wqs between the eatch of the K8 relay and the engine / bulkhead earth strap.

He had no more time to look at the car, so wrote the report up as Bad Earth on ignition side..

I have tried what has been suggested, jump lead from engine to the bulk head earth strap on the fuse box side of the car, this still soes not resolve the problem.


Any thoughts ???

Richard