Mercedes Benz repair: 1977 450SL Cranks but wont start, crank sensor, car wont start

Question
Fuel Accumulator is bad replaced, getting + 75 PSI from Fuel PUMP to Fuel Distributor main input.

Cold Start Valve Spraying
Thermo Time Switch working
Injectors 48 PSI and spraying on each cylinder.

TDC checked Cylinder 1 and distributor pointing to Cylinder 1,  we DID  NOT take thevalve  cover to check TDC alignment at the CAM  just in the front where the belts are hooked up.

Last time it was working I replaced the the AIR PUMP and now it just cranks but would not start.

Help,
Ernie

Answer
Finally get someone who knows what there talking about besides the same old question car wont start . Anyways it seems that you are getting adeqate fuel to the rail. The problem then would be either spark or compression or you may nave a disconnect hose on your IACV or I believe on your model there is an air valve that controls the IACV. Anyways pul the first plug and verify that you have spark to the firsdt plug after you set it to TDC. If you have spark then the problem lies in compression or air. if there is no spark check your voltage to your battery and with key turned on check your x11 adapter to verify there is same voltage to your Ignition control switching unit. if there is is the same then you must determine whether it is your distributor or Ignition control switching unit.(black pronged box)Also you have a crank sensor that will disable the car from getting spark to the cylinders which is located on the front by the flywheel it should be by your crank or around that area it sits in a port hole which tends to break after a while. Otherwise, I would also do a full compression check to see and probably pull the valve cover off. Was there a reason why you turned the crank to begin with ?? The air pump should not be at fault due to it is more of a emission control regulation thing than anything else