Please Help!!!

Please Help!!! Hot Start Problem
I dont know what to do anymore. I replaced every part I could think. New fuel injectors and seals, new fuel accumulator, fuel pump, fuel filter, spark plugs, distributor, wires, warm up regulator, fuel pump check valve, fuel pressure damper and I still have hard start problem on my 1979 mercedes 450 slc. When car is cold its start perfect takes 10 seconds to clean his trouth but after its get hot and I shut of engine for 10 minutes its takes 3-4 long cranking until its start again. When car is really hot and I crank it in the begining of cranking for one second it seems car wanna start and after that its just cranking and i had to wait last few times to engine cool down so i can start it. I am not sure is it vapor lock problem or it is something with ignition. Maybe ignition coil or maybe engine compression because i didnt check it.Also there is vakum leak in my car because after i shut of engine and lock a car passenger door lock but after one minut if i try to unlock only driver door unlock. So I am not sure if vakum has to do a lot with hard start problem. Also I am thinking that maybe is something with ignition because like i said first second of starting it seems its wanna start but after that it seems its floded.
Injectors are new so the only thing I can think of would be leaking cold start valve.Please help I am geting broke replacing all this parts and nothing hapens.

I forgot to mention that when engine is cold rpm is around 750 but when its get hot rpm goes less than 500 and i have to keep my fot on the gas pedal in order to car keep runing. Also rpm is higher when transmission is in park position.

[ctaylor738]

I am really grasping at straws here because you have done all that I would have tried.

Try capping the cabin vacuum fitting on the intake manifold to eliminate your cabin vacuum leak and see if that helps.

I don't know if this applies to your model but it does to my 63 220SEb. Iwas having a problem starting mine after shutting it down hot. I was later told by a Mercedes afficianado that it was a common problem with the M127 engine to have a mild vapor lock in the lines and that the solution was to turn the key on without engaging the starter for a minimum of 15 seconds allowing the electric fuel pump to purge out the vapor in the line and then engage the starter. I adapted that procedure and ever since I have not had a problem starting a hot engine.

[Mark DiSilvestro]

Have you checked to see if the cold-start injector is leaking or if it's still getting power during hot starting, from a defective thermo-time switch? If the cold-start injector isn't leaking, try unpugging it's wire and see if that helps.

Happy Motoring, Mark

I will try everything you guys suggested. I'll let you know what happened.