Weak sparks, or no sparks

[DreviHUN]

Hi everyone!

I recently started working on my ek4 (i have/had the d14a4, 90hp version of it).
I have already put on a d16z6 head, d16z6 distributer (td-42u), d16z6 intake, and the whole engine cable harness is remade to work with the d16z6 sensors and injectors, I have repinned the ECU harness for the obd1 (a virgin p28) ECU.
Everything went well, i double checked every cable and every solderjoint and end connecter, everything seems fine, however my car wont start.

The ECU throws code 21 and 22, (the vtec codes) however theese should not effect the startup of the engine. I have tested both of these issues according to the service manual and nothing is faulty, or maybe its the ECU itself, i dont know at this point.

I noticed that my sparks are really weak, at the start of the crank there they are visible but weak, bubt after 4-5 turns its gone complitely.
I have replaced the distributer, the sparkplugs, and the sparkplug wires, but still nothing, i have checked and everything is on mark, where it should be. I used the grooves on the distributer and the timing marks on the crankshaft pulley, because the sparks are so weak that even the stroboscope is not detecting them. Im thinking its the G101 grounding point, I did not install that one, but i havent seen anyone who has installed that, so Im not sure at this point.

Please someone help me out, I'm stuck, and out of ideas.

P.S. Thanks dodo for this whole guide and forum, it has been a pleasure to work by your guides, much love! :*

[Dodo Bizar]

Hey man, welcome to the board! You're the first real active member in a looong time I can tell. But good news since I am revamping the DU website this year.

Fortunately you provided the answer yourself I guess. G101 definitely has to be there, 100%. Even bad connections on G101 are very well known to cause all kind of random errors to happen, let alone not connecting it. G101 is the main ground for the whole ECU and main harness system and all ground are split from there. Without this one I guess ground is only very limited with very high resistance through the ECU casing ground if it is there...

Yup, really connect G101 and then see what happens.

edit: and clean G101 before connecting!

[DreviHUN]

Hy dodo, it feels like I'm speaking to a celebrity

Okay, now G101 is connected, nice and clean, there is a .15 ohm resistance from the battery so it's good. Well good enough at least.

There is only one little hiccup, sparks are still nowhere to be found.

And now I'm screwed, I don't have a clue what could've gone wrong.

[Dodo Bizar]

Double and even tripple check wiring is my first hunch. This year someone around here had similar issues. Spent weeks debugging the car and I had looked at it one day as well. Eventually he found 2 wires being swapped including the 12V.

In the meantime I try to think of any other things that could be the culprit.