The topic pretty much says it all. I have no spare key either. When working on the car, they must have dropped the keys and lost the chip that goes in the ignition key.
I have two questions: (1) Is there any way to find which chip I need. I already tried GM and they were of no help. (2) If that route isn't possible, is there any way of telling what resistor I would need to trick the ECM into thinking it was there? I have a '90 LO3 if that helps. Thank you in advance.

 

Why is it that mechanics always try to pass their screw ups onto the customer. Don't let him get away with it!

Anyway to answer your question, there is a great artical written by 92RSB4C (I think it was him) Here

Also, shame on you for not using the search button!

 

the only thing you can do is go to radio shack,buy a bag of resisters,they're tiny little things,and they're cheap.locate the thin 2 wire wire harness at the lower part of your column.unplug it and one by one put a resister in the unplugged harness.not the part going to the column but the other part of the harness.with each one try to start the car,when you get the right one the car will start.i know cause i've done this.let us know good luck.

 

 

the dealership will or should have whats called a vats interrogator, all it is is a seperate ignition switch that the vats will plug into and it has the 15 different resistance values, once they find it they can cut a new key for you with the correct resistance, since the mechanic lost the keys they need to pay for the time in the shop to find out which one it is, its an easy thing to find but takes time since the vats goes inop for about 5 min for each time it gets the wrong value.

hth