So my bone stock 1995 Civic EX sometimes has trouble priming the fuel pump in the morning. When I switch the car on, the CEL always comes on, but it sometimes takes some time for the main relay to actually engage and prime the fuel pump. If I wait long enough with the car on, I hear the relay click, the pump primes, and the CEL light goes out, at which point the car starts and runs perfectly. It takes anywhere from a few seconds to minutes for the pump to prime. The problem definitely gets worse when it is cold and wet outside, which leads me to suspect it might be a bad solder connection or something, somewhere. After I get the car started and running, I never have the same issue for the rest of the day until I go to start it again in the morning the day after.

I've searched up quite a few threads about people with similar issues, but it always seems to come down to the main relay. I didn't see any other solution.

The first thing I did was open up the main relay and reflow all the solder joints. They looked fine from the start. Indeed, this did not fix the issue.

Right now, I have the stock P28 ECU out and opened up. Is there any particular capacitor or solder joint that is known to go bad? Any tests I can do? Am I looking in the wrong place altogether? I don't know the first thing about these things, so any pointers or advice on what to do is appreciated. Thanks.

 

See this other recent thread where a bad capacitor was found.

https://honda-tech.com/forums/honda-...oblem-3351472/

 

Visually all capacitors and traces appear pristine, but I will try replacing those ones tomorrow.

 

Juicy update:

I decided to go ahead and replace all the capacitors. The two largest ones looked fine all around, but a few of the smaller ones were leaking a bit from the bottom. The leads crumbled off when I tried to desolder them. Once I replaced all of them, the car primed and started without issue. I will keep monitoring morning starts and update if I run into the same issue again, but I'm pretty sure it's solved. Thank you.