Hello I am in the process of finishing my project car and I’ve ran into some issues after it being assembled. When I try to start it the fuel pump doesn’t prime unless I jump the wires shown in the pictures. And when I do jump them the car still doesn’t want to start, brand new dizzy, main relay, P06 ECU from Xencron and rywire obd1 harness. Any help is greatly appreciated.
https://cimg9.ibsrv.net/gimg/honda-t...5f4801b28.jpeg
https://cimg1.ibsrv.net/gimg/honda-t...066b6715a.jpeg
4th wire on top of A ECU connector (fuel pump)

I have the same exact issue. I have a background in low-voltage so I checked if there’s any breaks in the lines and there were none which means bad ground. When I jump the pump turns on just no dice when I don’t jump. You have a bad ground. I replaced the main relay, made sure voltage was at each location before finding out that the main relay is grounded inside the ECU unit. It’s only five screws to open it up and four bolts to take it out. Opened mine last week and sure enough The ground fuses for the main relay were blown inside the ECU. You can either re-solder or get another one from the junkyard. Also just to add I’ve heard it can be a loose fuse inside the main relay. You can use a flat head to open it up gently and re-solder whatever you see blown.
Eric the car guy on YouTube will show you how to fix the main relay.

I found out about the ground problem of the main relay in these forums. I will try to look for the forum that has the exact number of the fuses so when you open up your ECU you can identify which are the ground fuses for your main relay. You’ll save yourself a bunch of money finding out if the ECU has a bad ground. I just spent a bunch replacing everything and all I had to do was pull out an ECU from the junkyard to fix.

Here
https://cimg2.ibsrv.net/gimg/honda-t...d24fb93e49.png

Here it is. Hope it helps
https://honda-tech.com/forums/honda-...-92-a-2640218/

I just bought this brand new ecu less than 2 weeks ago from xencron, they apparently test them before shipping it out and when I opened it up to put my base chip in the socket, the circuit board looked prestine. I’ve tried multiple relays as well, we’re almost thinking one of the wires needs to be repinned but we’ve never ran into this problem working on it before.

Yes, I had the thermostat housing powder coated but we sanded it back down to the metal and has continuity

that’s an amazing question. I’ll check right on that thank you.

it’s a shave and tuck build, very visible.