Hi, it's my first time posting here and i'm not sure if this is the right forum or not. I have a 1997 Civic MA8 with a D14A2 engine. Today i resoldered my main relay since it started causing trouble the past month or so because of the cold weather. When i went to test it after, i plugged it in and turned the key to the on position, fuel pump primed instantly but the CEL stayed on. Car barely started and it ran at about 200/300 RPM for 2-3 seconds before it died. I tried starting multiple times but the CEL didn't disappear and car did the same thing. I took the key out and let it sit for 30 seconds or so, the next time i tried the CEL disappeared like it normally would and the car fired up instantly and ran fine. Immediately after it fired up i shut it off and tried a couple more times and everything was fine. It used to do this occasionally before i resoldered the relay too but it never primed the fuel pump before, this time every time the CEL stayed on it primed perfectly. Tried a couple of times during the day but it never did it again. It usually needs to sit overnight during the really cold hours for the relay to stop working again and i'd have to sit there the morning after turning the key to off and on for a solid 5-10 mins until the relay finally clicks. I ordered a spare relay from a known working car but it won't arrive until thursday next week. I've checked Coils, Distributor and Spark Plugs a week ago before boiling it down to the relay. Could this be a ECU problem, or i just screwed up the soldering?

 

The symptoms you mentioned sounds like what I experienced recently. I had a cel that randomly popped up sometimes while driving but it would usually be gone on next start up and I didn't have any engine problems so I left it alone since my car is OBD1 and I can't check the code if the cel goes off. I went on a trip with the car, up north, and experienced some cold weather. That was when I had a couple of issues with the engine sputtering really bad while driving and when I was at a light it got really bad I was only able to keep it running by holding the gas petal. Finally the cel stayed on and it was code 3 MAP Sensor. Luckily I keep a spare MAP with me and after switching it out I had no more issues. I did have the cel return on the drive home but no engine issues and the light eventually went back off. I'd suggest scanning your codes, since you have OBD2 and if no codes show up try checking historic faults and the unconfirmed faults. If you can't pull a code try swapping the map sensor because those symptoms sound very similar to mine.