Hello everyone, this is my first post on this forum. I apologize in advance, but I'm trying to provide any relevant information to anyone who might be able to help, and the most I've ever done to a car is replace the alternator. Thanks in advance for reading.

I bought a 2000 civic ex 3 days ago, and as I was driving home at dusk, I realized my instrument panel lights were not working (tried adjusting the dimmer, no luck, headlights were on). I figured this was an easy fix, just a blown fuse. This morning I tried replacing the appropriate fuse and it didn't fix the problem. I looked around and saw some possible issues with aftermarket stereos being improperly installed or just a faulty dimmer, but since it was a used car I didn't know if replacing the stereo had caused the problem, and I decided to leave it alone for the time being and do more research. However, when I was replacing the fuse, I looked over the rest and noticed that a number of them had been replaced at some point with the wrong fuse (10 A fuses where there should be 7.5 A fuses, etc).

While I was replacing one of these fuses, I caused a short near (or maybe in) the fuse box. I'm pretty sure the spark came off the metal piece that holds the engine computer interface (at least, I think that is the plug right there). When I started the car after the short the engine sounded very bad, bad enough that I immediately turned it off for fear of causing more damage. I pulled of the piece of trim that covers the area under the steering wheel to look for exposed wires near the fuse box, and I found one exposed wire (black, coming out of the C913 plug) and a cut, uncovered black wire bolted to the metal piece directly under the steering wheel. When I checked the fuses after the short , the only one blown was to the stereo. I should also note that right after I tried to start the car, I saw some smoke coming from the firewall in the engine compartment on the driver's side.

So my questions are, does anyone have any ideas about what could have happened here? Any chance of a quick/cheap fix? Does this sound like a fried computer? Right now I have it scheduled to go into the mechanic Monday, but I would prefer to not have to do that, or to at least give him as much information as possible before hand. Any other advice or things to look for or try?

Thanks again.

tl;dr I was replacing a fuse, caused a short. Now the engine is barely running.

 

Try to find where the smoke came from. Look under the hood for wiring that's not stock, I bet there's plenty. There is also another fuse box there near the battery. Engine may idle badly after power to the ECU has been lost until it can recalibrate. I'd be more concerned about the potential fire issue. Also clearly the stereo needs to come out to investigate its wiring.

It's always good practice to disconnect the battery before working on the electrical system.

 

Thanks for the reply. From now on I will be disconnecting the battery when changing fuses. I had always thought that it was standard procedure to just turn off the car. Oh well.

So, given my situation, I am reasonably safe from causing engine damage by running the car?

Also, as far as I can tell, the only non-stock wiring in the engine compartment is the cable from the battery to the amplifier powering the subs. This is fused and looks reasonably professional.

 

Well, my mechanic has had the car now for two days. Apparently today he blew out a spark plug, with the treads, on the number 3 cylinder trying to get this thing to run. It seems the ECU is reporting back that it is ok.

Please, assuming he hasn't already ruined the engine, does anyone have any idea what this short did? Before he causes more damage?

 

That happens after the plug is already loose. An electrical issue alone won't do it. The threads can be replaced but it usually means taking the head off.