Zac26

First of all I'll explain the specs on the car..

It is a 91 civic with a b18a1 swapped into it with a pr4 obd0 computer.

A while back I bought a 91 civic that already had a b18a1 swapped in it. The car has ran fine for about a year now until one day I turn the car on and it shuts down right away. It then would not start until the next day. I drove it home, then drove it around for a bit, shut it down, then it would not start up again. The starter cranks perfectly fine though.

I've been diagnosing this for days now. I have no spark, no fuel pump priming, and the cel comes on with the ignition and does not go back out. There is no cel code on the ecu led though and there were no cel codes present during the time the car was running.

I stupidly jumped the gun and installed a new distributor, but the car will still not start. So I pulled the main relay out and tested it. I had all three clicks and continuity between all necessary pins. I pulled the cover off and noticed someone has already applied new solder. I then tested for continuity between the ecu and the distributor plug and all wires are intact. Also, the distributor is getting power
I then tested the main relay harness in accordance to this link https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/checking-main-relay-pics-2535047/
I discovered the ignition wire is only carrying 3V. This is not enough to charge the coil in the relay. Also, I know the reading is accurate because I used my multi-meter and my test light. They are both reading the same.
Now I am thinking that I should test the ignition switch, but to be honest I have no idea how. If anyone knows how to test it or have any other ideas that would help me solve this it would be much appreciated.

Zac26

Also, I forgot to mention, I wire brushed and cleaned the thermostat ground, the valve cover ground, the transmission ground, and the battery ground.

turbomaniac

i cant remember if there is an immobilazer system to the obd0

if there is any, try to deactivate it and see if the problem remains

if there is any antitheft system, also deactivate it...

it seems to be sg like that...

br8crumb

well if ur check engine light is ON before you even start the motor, i wanna take a gamble and say something isnt plugged in. its obd0, its not like the codes stay constant until fixed, they usually clear when u turn the car off and arise when it comes up again

Zac26

Solved it... sorta. There was a bad orange connector behind the fuse box that was between the ignition and main relay. When i wiggled it, the voltage on my relay harness started changing. My 3v started jumping from 1-12v. I tie wrapped it into a position where it stayed at 12v, plugged the relay back in, and the car fired up.

Now the car is temporarily running but I was wondering if anyone can recall what orange plastic connector I'm talking about. I'm not sure if it can be bypassed, or if it is a voltage splitter. I would rip one out of a scrap yard car to take a closer look, but there are no EF's in any local yards.