Starting Trouble When Warm
 

I have a 1979 450SL. I've had trouble starting the motor after the engine is warm. I've replaced the fuel accumulator and check valve. The car starts a little better but it still turns over and over (about 10 seconds) before it starts up. I have one or two fuel injectors that could be leaking. The mechanic that worked on the car checked the pressure with a guage and it held for about 15 minutes and then it dropped just a little. I'd hate to replace the fuel injectors and that not be the problem. Does anyone have any ideas about what's causing the warm startup problem?

Could be the fuel damper (next to the pump)
 

My friend's 6.9 has that problem and he was told it was the fuel damper.
A trick to starting warm is to put the gear shifter into reverse, try to start the car for a couple of seconds, then put it back into park and start the car.
Apparently this pumps some fuel into the system before you start the car.
Hope this works.

i think that the trying to start in reverse a couple of times is the same as cycling the key without start position about 3 times without causing other problems, and i think that 1 or 2 injectors may not cause a no start condition unless there are underlying probs.....it could be as simple as coil or something else.........just my opnion

The idea of trying to start with the >>>
 

auto in reverse is to pump fuel into the system to overcome a lean condition when warm. This will not work by just turning the key to ignition a couple of times.
If turning the key to start with the auto in reverse works, it means that there is a lean fuel condition when warm, which could be the fuel damper.
If it doesn't work, then it is something else.
This is just a quick test to try and work out where the fault lies.

PS; This test worked with the 6.9, he was able to start the car much easier when the motor was warm.