Weird electrical problem.
Posted: Thu Feb 02, 2023 8:56 pm
So for a little bit of background I have a 94 Civic DX with a B18C1. I'm running a P28 with Neptune RTP. Cars gonna be 30 years old next year and I've definitely had some electrical gremlins start popping up. The most recent one mimicked a bad main relay which was easy enough to replace. Unfortunately it did not solve my problem.
Basically I'd get into the car and turn it to accessory 2 and the CEL would flash on and stay on... and the fuel pump wouldn't prime... just silence. Like I mentioned I already replaced the main relay and beyond that I confirmed my fuel pump was working per the OEM service manual. Well one day I was just sitting there, same situation, in a rage, and randomly I heard the fuel pump prime and the CEL click off. Car started right up, warmed it up. Turned it off and turned to accessory 2 and pump primed and started just fine. Continues for a couple of weeks and it worsened the longer it sat without running. Basically you'd just wait longer for it to randomly start to work.
Doing a little digging on the web and came across a thread where someone mentioned checking the capacitors in the ECU. Thankfully everything's on youtube these days and I came across this... way too long video https://youtu.be/J8gegX4eYJE. Ordered new capacitor set which came in today. Sure enough after identifying a suspect capacitor and replacing it I popped the ECU back in the car and holy shit everything works just as it should! I went ahead and replaced the rest of the capacitors so I hopefully won't have to do it for another 20-30 years. Hope this helps someone.
Basically I'd get into the car and turn it to accessory 2 and the CEL would flash on and stay on... and the fuel pump wouldn't prime... just silence. Like I mentioned I already replaced the main relay and beyond that I confirmed my fuel pump was working per the OEM service manual. Well one day I was just sitting there, same situation, in a rage, and randomly I heard the fuel pump prime and the CEL click off. Car started right up, warmed it up. Turned it off and turned to accessory 2 and pump primed and started just fine. Continues for a couple of weeks and it worsened the longer it sat without running. Basically you'd just wait longer for it to randomly start to work.
Doing a little digging on the web and came across a thread where someone mentioned checking the capacitors in the ECU. Thankfully everything's on youtube these days and I came across this... way too long video https://youtu.be/J8gegX4eYJE. Ordered new capacitor set which came in today. Sure enough after identifying a suspect capacitor and replacing it I popped the ECU back in the car and holy shit everything works just as it should! I went ahead and replaced the rest of the capacitors so I hopefully won't have to do it for another 20-30 years. Hope this helps someone.
