380se no start in crank position

Hello Hello My 1984 380se has some starting problems, it kind of goes like this, turn key to the on position and you dont hear any noise but the lights on dash light up as normal. Turn key to start position and engine cranks over good and strong but will not fire any of its cylinders until you let key return to the run position. It will do this every morning and somtimes will not start at all if its really cold out. It was about 9 deg. out the other morning and could not get it to fire on any cylinders so i check for the 2 most important things to make this engine's world go around and found them. Getting strong spark from coil wire and from spark plug wire. Also pulled cold start valve out of manifold with wires and fuel line attached and watched it spray a bunch of fuel out while cranking. Now im thinking back to the old ford ignition systems that liked to only spark while cranking but not in run position, could it be that simple? Or do you think its the ignition switch? And I do hear the fuel pump and the idle air control buzzing after cranking for a few secounds. And it does not do this after it is running even if just for a few secound. Once it starts you can shut off abd restart normal. Any thoughts on this one guys. Thanks for your time

[HarryM]

Disconnect the (live) low tension coil wire and connect it to a test light. If the light does not come on while cranking, it's the ignition switch.

Thanks for idea Harry, but i have tried that before and i do get power to coil while cranking. Test light not as bright as when running but not abnormal with starter engaged. Also tried test light on ground side of coil and it blinks test light fast while cranking. Im thinking about checking to see if fuel control module is not getting power and or ground in the start position, but i would think it would still try to fire off the fuel the cold start injector is spraying. Does anybody know if its possible for ignition
system and cold start valve to work in start position but not the fuel control module? As in bad ignition switch? And does the ignition module send signal to anything else besides coil?
Thanks again

Come on you MB techs, you have had to seen somthing like this before! Give me a clue cause i dont have one. lol

I just tried this morning to jump power to start wire under hood over on the right inner fender with the key in the run position to see if it would start any better, as in ignition switch is not sending power to all the correct places when its in the start position. And it made no diffrence at all. still had to crank the hell out of it and it would nor fire a cylinder until i pulled jumper wire off of start wire, just like when i would try to start with ignition switch. I did notice that if i would tap the starter over quickly it would almost try to fire cylinder to sone and cause engine to spin backwards about 1/4 turn. It did start but still the same old story,
crank & crank and will not even try to fire cylinder until you disengage starter and if you timed it just right when you let off starter one of the cylinder would fire and engine would start and run like nothings wrong. I wonder if its possible that the ignition module is needing more volts then normal and not getting them while starter motor is engaged. And just when i disengage start and engine is still turn a slight amount the module is getting enough volts/amps to fire cylinders at the correct time.
The module is original, but i hate to waste that much money on a long shot. Or how about pick up sensor, could that cause the same problems And were is it located? In distributer or did this engine have crank sensor?
What ya think?

[Benzmac]

Located near the coil, there should be two resistors. One is for starting. IT gives the coil full volts while starting. The other is for running. It gives about 9 volts. My money is on the resistor.

Thanks Benzmac for your respond but after searching for the the resistors you are talking about and not able to find them I referred to the the MB service manual CD and found out that my 1984 380SE has the TSZ8 ignition system which replaced the TSZ4 system that you are talking about. My system does not use the resistors you mention. But you did help me in a way, while searching the MB cdrom i found the test procedure for my ignition system with all the volt/ohms values. If we have another slow day at work tomarrow ill pull it in and brake out the multi meter and perform test. Has anybody ever work on this system with this type of problem before? Thanks again guys for your input.

Got a used ignition module out of salvage yard last week for $20.
The car starts and runs perfect at all tempatures. This car has gone from the hardest starting car i have ever owned to the fastest, starting takes less then one revolution of engine nomatter how cold. Thanks for replies.