C43 W202 starting issues

[MilesMurphy]

Hi All,

I have bought a project c43 with a 55 lump from an s class in it. I ran some tests to crank the engine. I found that the starter works fine and the engine turns fine too. What I'm having issues with is I cant start the car from the key, although it did spin the starter motor from the key and a slight crank the first time. Now I get a click sound from a reply and nothing.
Could it be a relay that's gone, if so where? Or has the immobiliser kicked in for some reason.

The engine loom is from the 55, its been slightly chopped by the last person so I'm after a base level so I know what changes have been made. If anyone knows the closest loom that can match the 43 original (A202 540 71 07) loom that would be great as merc no longer sell it.

I double checked the starter and it fires up using a direct method to activate it. But when trying from the key I get nothing.
I have charged the battery and will give it another go.
I have also removed the fuel pump fuse for the moment as i just want to crank it not start it.

Apart from that everything works in the cars.

Thanks
Miles

 

[Blobcat]

@bigasotonuk might have some ideas

 

[MilesMurphy]

Quick update, I found the starter relay and ran a test.
Clicking can be heard
Resistance is showing as 1.0
So I would guess that's a faulty relay but I don't have another like it to confirm this.

 

[anyweb]

i'm not sure but isn't the immobilizer enabled via the IR in the key, if i remember you pointed it at the car or rear view mirror to 'unlock' the car (but also unlock the immobilizer), there are two leds, red and green, do they flash on your mirror ? and if so what pattern ? that should give you an indication of whether you have a problem in that respect or not,

if not, check the functionality of your key, it could have a faulty button

see > https://www.niallbrady.com/mycar/c220/fixkey.html

 

[MilesMurphy]

Quick update. Engine turns now. Engine earthing wire issue.
Next step to fire it up. But diagnosis brought up a p1570 code. Engine drive authorization. But again I'll need to check the fuel etc as this car has been sat for 2 and a half years.

 

[LostKiwi]

Two and a half years the fuel will still be ok to start with but will need refreshing before any decent drive.
My Smart started and ran ok with 3 year old fuel.

 

[MilesMurphy]

Hi,
Fuel looked dirty. I removed the old loom to check it. But to be fair it's the loom off an s class and it's been chopped in with wires by a garage to make it work. So I'll look for the closest one to the 43 loom. Then go from there as my current 43 (working) has some wires the this current loom doesn't.

Also the fuel filter lines were spilt. So I have a bit of work before it starts.
Whilst I have the engine jack up out- of the car I'll replace the plugs too. Maybe also are there any better exhaust manifolds that I can fit. I'd like this monster at 400bhp with other mods

 

[bigasotonuk]

Hi
You need to find out exactly what has been done to the engine wiring loom and why.
There is/was no need to touch the wiring loom when fitting a 55 engine in a C43.
As the engines are effectively exactly the same you fit the 43 loom to the 55 engine.

 

[MilesMurphy]

Hi
You need to find out exactly what has been done to the engine wiring loom and why.
There is/was no need to touch the wiring loom when fitting a 55 engine in a C43.
As the engines are effectively exactly the same you fit the 43 loom to the 55 engine.

Exactly, the 43 engine was sold with the loom by the previous owner. So someone thought to mess about with the 55 loom that was on the 55 engine rather than trying to source the 43 loom or build one

 

[alexanderfoti]

Quick update. Engine turns now. Engine earthing wire issue.
Next step to fire it up. But diagnosis brought up a p1570 code. Engine drive authorization. But again I'll need to check the fuel etc as this car has been sat for 2 and a half years.

Looks like you have a drive authorization fault. Without drive auth the ECU will not allow the engine to start. There is an immobilizer fault that requires further investigation. Suspect you will not get far without HHT or DAS on this car (MB diagonstics)

 

[MilesMurphy]

Quick update,

no drive aauthorisation issue any more and created a loom from a 98 e430 loom. Engine. All system reporting no faults