I usually don't post to forums that much because I'm pretty good at finding issues and fixing them, but this no spark condition is drive me crazy. I have access to the factory service manual for my car. I was able to use it for the MPFI control unit pin read outs for intense trouble shooting. 

Condition of ignition system

No engine codes in read mode.

Crank angle sensor is functional. Tested all 4 wires going to the distributor and it is reaching the MFPI control unit.

Tested Coil, it works when I take the negative post and I strike it on the negative side of the battery. Coil is good.

2 Wires going to the Power transistor that is connected to the coil are operational. one is out putting 12V and the other one is a Square-wave from the computer. ( i have pictures of the oscilloscope when I pulled the distributor out and put it on a drill)

The only area that I am having trouble with is the power transistor. I tested the ground and it has 0 ohms to the negative side of the battery. I got another junkyard power transistor and it didn't give me spark. Its weird that there is no testing procedure in the 1988 Subaru xt factory service manual for the power transistor. So I either got 2 bad power transistors or the square wave from the computer is not strong enough.

Does anyone know how to test a power transistor?

*all fuses are fine*

I got spark. It was the power transistor. I hooked up a newer transistor I had laying around and connected the wires and was able to get spark.

were the test procedures you used in the factory manual ?

 

It has IGNITION CONTROL SYSTEM troubleshooting flow chart. Step one is check for spark with a timing light, if no light then check body side of crank angle sensor ( 4 wires off the distributor) for 12v and 2 4v wires and a ground. If you dont have that voltage its bad ECU or bad wiring, you have to pull up the ECU pin read out at that point. After that you plug the crank angle sensor and you check for a 4-5 volt Square wave coming from the crank angle sensor. What I would recommend at this point is to disconnect all injectors and fuel pump so you can just run the distributor buy hand or with a drill. Next you need to check for voltage at the 2 - pole power transistor. One side needs to have a constant 12v, the other wire is a 12v square wave coming from the ECU. 

This is where the service manual left me. And it didn't have specific voltages for the square waves. It didn't even tell you that there was square waves.

The part they left out is that the power transistor can go bad( believe it or not). it should read out like any NPN transistor, you are going to have to look up how to test that. But you can with a multi meter with diode check.

You can replace the hitachi HF83118D1 transistor with any NPN transistor that is rated for the voltage and amperage. It will take some retrofitting and testing but it will work.

This has to be one of the most intense trouble shooting I have ever done. Check fuses first 😂

Well, I guess your part now is to record for posterity, and those who have tools and skill to see waves of any kind, record what you know to be good, and bad.

Did you test the transistor ground in the car? They are famous for the coil bracket getting dirty, and the transistor loosing ground.