W124 300d occasional no start

[Fergal1975]

Have a 300d that will not start on the key on occasion. Will have a clicking noise But if I cross the starter it will start up and turn off and it will start straight away on the key.

 

[mattkh]

Have a 300d that will not start on the key on occasion. Will have a clicking noise But if I cross the starter it will start up and turn off and it will start straight away on the key.

Me thinks you have a lazy starter motor.
Removing the starter, dipping the visible shaft end in some spirit to clean it, then dry completely. Check the starter before putting it back on the engine.

 

[Fergal1975]

When I cross the wires on top of solenoid it starts no problem maybe solenoid is weak ?

 

[mattkh]

When I cross the wires on top of solenoid it starts no problem maybe solenoid is weak ?

Could be.
I do not have a wiring diagram.
I would check/clean the starter relay if there is one on your car.
By the way, how heavy is the bunch of keys that the ignition key is on..?

 

[Fergal1975]

Only one key . ! I tried rattling key while turning made no difference . It's a 230 I put a 300d into swapped out ignition as well . Have a 280 petrol would the starter be same ?

 

[mattkh]

Only one key . ! I tried rattling key while turning made no difference . It's a 230 I put a 300d into swapped out ignition as well . Have a 280 petrol would the starter be same ?

Probably not.

 

[Fergal1975]

How would I know if the ignition is at fault is there any test I can do ?

 

[mattkh]

When I cross the wires on top of solenoid it starts no problem maybe solenoid is weak ?

If you can see the thin wire that activates the solenoid, you can check if it is becoming LIVE with 12volts.
If it becomes live every time of the turn of the key, then the ignition is OK.