I recently decided to get my late father's 91 CRX Si up and running and back on the road. It has sat for about 5 to 7 years and from what I remember it had a faulty fuel pump. I have dropped the tank and made sure it was clean and replaced the pump. I also replaced the main relay, fuses, and the fuel filter. The car spins up good but will not fire. I decided to take my multimeter and check for voltage and found out I have no power to the fuel pump. I checked the continuity on the main relay and it appears good but I did have another one and switched them out and still nothing. It does show power coming to the relay harness with both the car off and in the start position. I did unplug the ECU, {which is a pm6} and noticed a little rust at the bottom of the case so I opened it up and cleaned the board and made sure everything looked ok and none of the transistors appeared to have any damage. Now before you ask how did I clean it, I have been in the IT industry for over 20+ years and know how to properly clean boards and electronics. Still nothing after I got it back in the car and hooked back up. As to what to check or try next, I am kinda stuck so any help or guidance would be appreciated. I am by no means a mechanic but I am smart enough to follow diagrams and instructions. Just want to see the car on the road again.

 

I’d Check your grounds first If I remember there’s also a ground to the thermostat housing. Make sure it’s nice and clean

 

this link will be helpful I think.

chase power and ground starting at the fuel pump until you're at the battery. Main relay and ECU need power from the ignition switch, ECU needs to trigger the relay to power the pump. the pump needs good ground to do right when that power arrives. the ECU will only prime for a few seconds after initial power on, then should continuously when starting or engine is running.

 

thanks guys, will start at grounds and then work my way from back to front

 

When turning the key on, you should hear the Main Relay clicking, and the pump priming just until the yellow check engine light turns off.

 

Did you figure it out? I had a similar issue and got really familiar with the wiring and components for the fuel and ignition systems