thankful for any help..'93 sts has been sitting 3yrs,hot battery,starter is good,solenoid is good,key reads 2370 ohms,security light goes off,fuel pump comes on and off,switch ON can jump starter & it cranks but no fire,i think starter relay has fire to yellow 10ga.wire but none to purple or the 2 smaller gauge wires,have tried in both P & N .does anyone have any suggestions ? everything has fire except ign. & starter.

Not that familiar with your car, but a bad crank shaft position sensor would give you those symptoms. Fuel flow, engine turns over, no spark.

diagram says yellow goes to gear select switch then purple to start. you try putting it in nuetral? my diagrams arent very good though they dont say how the vats fits in. i believe there should be some tdm that stops cranking and also the fuel enable circuit to the pcm so even if you jump the starter it wont fire the injectors unless the tdm is happy and the circuit to the pcm is good

i think that the vats is causing this.if i jump this relay the starter cranks,but no fire for to plugs.the small gauge wires to this relay don,t get fire in the on or start position of the switch,this is what makes me think that the vats is playing a part.the relay is located in the interior trim along rocker panel.the yellow 10ga gets fire in the start position,but pretty much goes to a dead end at the relay.the 10ga purple when i jump the relay engages the solenoid and starter.i haven't tried the resistor trick yet for the passkey,but i did find the 2 white wires.

Does the SECURITY light flash while attempting to crank?

pcm drawings say;
on the 4.9 it says 3f10 dbl to passkey decoder module
northstar says 3e6 DG/2c8 dbl to passkey module.
GM VATS Bypass Module For LS1 and LT1 GM VATS Bypass Module For LS1 and LT1 [gmvats] - $24.95 : 3rdBrakeFlasher, E-commerce web site

i would see if you can find the module and see if you have a signal coming out. it is likely a 50hz square wave on that year. so you could solder that bypass module to the pcm, make your own starter relay circuit so when you turn the key to start it puts 12v on the purple wire