weak signal for coilpack 1 and 4

I have two wiring diagrams. One shows a single 12v wire from a fused source that branches into two wires, one for 1-4 coil pack one for the 2-3 coil pack. My second diagram shows two relays one to each coil pack. Which one does your Evo have?

can you share those diagrams. thank you!

the first of my two pages was missing... I found it tonight. It's a single ignition coil relay for both coils. The 12V feed from the relay splits to each coil. Do a voltage drop test on the 12v feed wire to coil pack 1-4 while cranking. You have static 12v on that line however if has resistance on it you will not get the full 12v needed to charge the coil and you will have a weak spark.

this is my first time seeing the first diagram picture.
to make sure i understand correctly,
you want me to test the 12V feed to coil pack to check for a voltage drop.
i actually ran a test where i provided coil packs 1 and 4 my own good ground and my own good 12V power.
neither gave spark.

only way i was able to get spark on 1 and 4 was by jumping the signal wire from 2 and 3 to 1 and 4.

I missed or forgot you did that, sorry. This defies logic. If the ECM works on another engine and both coils work on 2-3, good power, good grounds then it has to be the connection between the ECM and coil. You used a proxy wire with no joy so to me that suggests the pins inside either or both connectors at the ECM and or coil. Note that the 1-4 coil ground has two block connections and ties to 2-3 ground. It's not just a single ground point.

I did not know that is has 2 grounds.
would you be able to tell me where those grounds are located? i will check them to make sure that is not the issue.

Bottom of page is front of car... right side of page is driver side of car... ground points 10 and 13. Hope this helps

Thank you so much. i will check this on Monday and update. your the best!

Grounds disconnected cleaned and put back on. Still no joy. This is blowing my mind.

Hallo mate...can anyone help me..
I have the same problem..coil 1-4 no spark coil 2-3 has spark engine runs with only two cylinders. I have changed all the things crank sensor, cam sensor, coil changed still no change..when I read your problem is the same as what happened to me. is there a problem from the ecu or something else. coil has 12v, ground ok, signal from drive 1-4 reading is not the same as signal 2-3.. is there a problem from inside the ecu