starter wont crank unless I slam shifter into park with key in start position

[79-Big10]

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[Irish_Alley]

is the shifter sloppy? is there a lot of play in it if you go into the engine bay look at where the column comes out and check the linkage see how much play is in that

[75gmck25]

I would have guessed NSS problems, but it sounds like you already tried troubleshooting that and had no success.  One final step is to jumper the NSS using a short wire with spade terminals, just to see if the problem goes away.

The other common problem with the ignition switch is that the ignition rack inside the column is broken.  Its a small pot metal piece (the rack) that moves a rod and connects the column switch (where the key is) to the actual ignition switch mounted lower on the column.  If the rack breaks partially the rod will not move correctly and the switch may work in some positions but not in others.   

Assuming its a broken rack - A GM ignition switch rack is available from parts dealers in the Help! or Dorman carded parts section and it usually costs about $12.  However, there is a lot of dis-assembly required to get to that small part.  You will need to remove the wheel (wheel puller) and remove the lock plate (GM lock plate remover), and then remove parts until you get down to where you can replace the rack.   There are multiple articles on line that show the process, and many have good pictures.

Once you get it the steering wheel  broken down that far you may want to go farther with the dis-assembly and tighten up the three vertical bolts that hold the upper assembly onto the column.  Most folks lock-tite them in place to keep them from loosening up later.   I ended up taking apart my column twice because I did not tighten these bolts the first time.

Bruce

[bake74]

     I would start with the NSS and test it, I bet you will have to replace it.

[79-Big10]

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[bake74]

     Too jumper the NSS you will have to put the jumper on .8 DK BLU-75 and .8 LT GRN-24 socket.  see upper left corner.
     Those 2 incoming wires are the NSS for auto and manual transmissions.

[79-Big10]

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[79-Big10]

Ok, now have turn signal switch removed to find the actuator rack, pinion gear and rod in excellent shape. The is no spring in there that I could see. My new lock  cylinder does not spring back to run position from start position, any ideas for fixing this? DAVE

[Irish_Alley]

this might help
http://www.crankshaftcoalition.com/wiki/images/d/d6/Jazzman_Steering_Rack_Rebuild.pdf

[bake74]

this might help
http://www.crankshaftcoalition.com/wiki/images/d/d6/Jazzman_Steering_Rack_Rebuild.pdf

     Irish, great informative article.  I will be saving this one.
      79-Big10, I believe what you are looking for starts at page 21, though the whole article is good information.  Not sure if it will answer your question though.
     It also doesn't look like you were pointed to the thread in the tech section on rebuilding a sloppy GM steering wheel by CaptKoas so here it is, enjoy and hope this helps.
      I need to rebuild mine also, but it is not at the top of the list yet so I have not gotten to it, but it sounds like since your key will not spring back that logic says it has something to do with the sector preload spring or something with the rod itself is getting stuck, sorry could not be more help, just haven't taken 1 apart yet.

[79-Big10]

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[bake74]

      I know what you mean by not knowing how it goes back together when something "falls" out and you did not see it.  In the past I have done what you are doing, try, try, try, and if I can not get it, then I read and ask others.  If that does not work I usually end up going to pick-n-pull or an auto salvage yard and seeing one myself or taking another apart to see for myself.
      Good luck and keep us updated on your progress.