Ok this is a 94 Integra 2dr 5spd...I was throwing a code 43 ( Fuel Supply System)...so I removed the main relay/fuel pump relay and resoldered the soldered point on the relay but didnt desolder any of the old solder points but I've done this b4 with both of my 90' Integras and it worked fine...So I resoldered the relay on my 94 Integra..re-installed the relay back in the car....Car started up fine all three times and the 4th time, everything died completely there was no power to nothing!! Last night, I was testing with testlight both fuseboxes, some wires under hood and under dash as well as all the fuses...Battery is brand new within 2 months ago...Was getting power to the fusebox under hood so no blown fuses under hood as I checked with test light....but theres no power to fusebox under dash...I bought a new main relay and installed it....Now after awhile of sitting...power randomly came back and had all power but when tried to start the car..everything die completely again, so I waiting a while and power came back so I just stoped what I was doing...armed my car bc my driver door doesnt lock inside for some reason prob the rod and the key lock has been siliconed in the tumbler by some random ***** i guess awhile back so the only way to lock my driver door is to use my alarm to lock and arm car...so car has been sitting since last nite with power still running to alarm bc led is still blinking so I'm assuming there is still power throughout the car but I know if I try to start the car...I'll prob have no power again...So I'm stumped...I know from basic knowledge and some schooling that the problem could be either some relay(s) somewhere in the car, fusebox under dash maybe, or the wire harness throughout whole car or just in the cabin....So like I said..the battery and main relay are brand new now so Dont know where to start and what to do...not knowledgeable of electrical issues but this is a time for me to learn but need to be steered in the right direction...

 

Check your main grounds, batt. post and cable clamp, batt. to chassis ground and chassis to engine ground, don't just eyeball them remove/clean/reconnect.

Having power and loosing all of it when you try and start the car is going to be a bad ground 99.99% of the time, the bad ground can not handel the current needed by the starter so the poor ground you do have "opens", it is a very common problem, we fix bad main ground on cars 2-3 times a month at the shop. 94