Engine does not want to start after rebuild-ideas

I put a harmonic balancer on backwards once.(letters were upside down when looking from the front of the car) I had compression, I had spark, and I had fuel. I had all the right things but just not at the right time. I swapped the balancer around and the car started right up.

If I understand correctly, you used an 84 Euro block but your original '80 fueling?
You got a wiring harness from Motorsports. Is it the correct one for the CIS?
What distributor are you using? '84 Euro is LH which uses a CPS to time ignition.
I'm sure you know all this, but I'm just trying to help us brainstorm a solution.

Again - John thanks for any insight. I appreciate your time.

I made sure the harmonic was correct - even validated in the Porsche manuals - I got very excited when I though I had put it in wrong - crap - I did it correctly.

Using the CIS from 80 - wiring harness for an 80. I used the 84 lower end but used my 80 oil pan, all bolt-ons' came from my 80. I am really quite perplexed. I even used a compression tester to make sure that the TDC was on the compression cycle - unfortunately it was. I am using the distributor from the 80 since the heads and cams are from the 80. I turned the motor two rotations to validate that the timing/cams/rotor were all in sync - again it looked correct.

My next idea is to put the old/OEM starter back on. Just thinking that there may be some electrical issues with running. There was some notes about issues in the instructions from 928 motorsports.

I'm thinking a 9mm to the body will get it's attention.

Again - Thanks for you time and all brainstorming is greatly appreciated

Jordan if you do have compression fuel and spark then its a timing issue either with the when the spark arrives or fuel is injected.

If possible can you can back to the original harness and all other components even just a temp hookup to see if it will fire up.

I wish I could but the old harness literally is falling apart. I have been going over everything again and may have found something. I was checking the plugs and found I was shipped 1985 on plugs. Got the right ones but then rechecked the spark with the plug out. It looked really weak and did not have the usual snap sound. I have checked the voltage on both sides of the coil. I have 3 on the 1 side and 5v on the 15 side. I would believe that there should be 12 on either side but I cannot find any reference as to what it should be. In my domestics I look for 12 on the positive side of the coil.

Any ideas as to what could be causing this?

Check the sensor that that gives the position of the flywheel for the timing. I have the same problem the sensor was good but the ring on my flywheel had slipped had to line the ring back up and put a small tack weld on it to keep it in place. Finding that drove me crazy and about 10 Porsche mechanics. I also spent 3 thousand dollars by parts that i did not need. Good luck!!!!

Im not that familiar with the older models if they were fitted with a CPS (Crank position sensor)?.........if so was it changed?