Zarbuck:
First and foremost, "welcome" to Pelican! You have come to the right place for answers and for help from some of the finest people in the Porsche community!
Second, if you need to find out if your DME/ECU (computer brain) works, there are two (2) options. 1) Send it to IAN at 944online in Florida, he will test it for you for free. 2) On this forum is a member named ischmitz, his name is Ingo and he fixes ECU/DME Porsche units. This will save you some time and money.
Third, and most important: As stated by members above, before you start spending a bunch of money on this "non-starting" 944, please make sure you have covered the basics. These are as follows:
a) does the car have spark
b) does the fuel injectors get 12V (use noid light to test)
c) does the fuel pump run
As John has mentioned, the Clarks-Garage has many write-ups on how to troubleshoot and narrow this down.
Now, I have always said, "it's always something fundamental" and it usually is. Such as, if the battery is charged, or rather was charged at one time, is it still showing a charge of at least 12.5V when idle? If not, there may not be enough voltage getting to the fuel injectors or the other electrical circuitry to start the car.
The reference and speed sensors play a vital role in ensuring that your car starts and continues to run.
One test not mentioned earlier is this, try spraying some starter fluid into the AFM and see if your car will run. If the car starts and runs for a short time, then your problem is electrical and the most likely cause is the reference sensors not being hooked-up completely or they are faulty.
The DME relay by-pass wiring shown in Clarks-Garage will ensure that your fuel pump is running, so your car will start if it is getting the correct voltage. Also, ensure that all of your grounds are clean. There are several places on the car's body that these grounds exist. There are ground connections near the front of the car near lights on the frame, on the back of the engine bell housing right near the sensors, and most importantly under the dash on the driver's side.
Hope this helps and good luck.
