no spark

Can someone tell me how to test a 1991 celica that has no spark. Thanks.

Is it just one spark plug that has no spark or all 4?
things to check
1. dizzy cap and rotor arm
2. earth lead off your distributer
3. battery/ terminals
4. Main coil lead - goes from your dizzy cap to your coil.
5. the coil itself (supplies the power to make the spark)

I have no spark to any of the plugs. I was told to check the power transister mounted on the firewall, but I really don't know how. Thanks.

The power transmitter is the coil. they dont last forever and are dead easy to replace if that is indeed the problem. It will give you a mighty jolt of electricity if you touch the wrong part of it when its powered up so be carefull.

I have no spark to any of the plugs. I was told to check the power transister mounted on the firewall, but I really don't know how. Thanks.
did you say transistor or transmitter? a transiator for example can be used to turn on and off the poer to the coil primary side, but they are usually internal on modules and have no way of testeing them. however depending on the year of your vehicle autozone might be able to test the module for you.
other things that you can check is resistance on your coil, primary and secondary sides once again autozone might be able to help you with the specs. good luck and keep us posted

It was a bad coil. Thanks for the help.