250SL Injector woes
 

Got a 1966 250sl which is overfuelling. Runs for thirty seconds and then stops. I decided to crack open the injector pipes and to see if it was poor pump pressure or over. To my horro as soon as you turn on the ignition and the electric pump starts, petrol starts pouring from all six injector pipe. All of them are open, so I presume the plungers are either all stuck or dead. Any ideas and where can I get a technical drawing of the injector pump block/distributor ?

Take the test port hex plug off from below the Cold Start vave on the intake .
Turn key On .. If fuel comes out of port, the valve is stuck open. Fuel should only come out when the key is in the START position..

Also, check for 12v at that wire .. Again, only power when in START position...

25 SL injector woes.
 

Tried that. Have correct supply to the cold start valve and it opens and closes as it should. Still does not explain why the injector pump itself is open on all six injectors ? Surely it shouldnt be ? The njectors are spraying constantly in all six cylinders as soon as you turn on the ignition. Is it easy to rebuild the pump ?

<<The njectors are spraying constantly in all six cylinders as soon as you turn on the ignition.>>

I see ..
Well , that is hard to believe , as the electric fuel pump feeds the FI pump with approx 15-18 PSI and if the key is On and the FI pump is not running , you certainly would not have the required pressure it takes [approx 265 PSI] to open each injector. Are you telling me you have 265 psi at every injector without the car/pump running ????????

You may have a stuck rack on the pump, but the pump plungers have to be moving to reach the injector pressure opening specs.. there is no way the electric pump is opening your injectors .
Do you know where the injectors are ???