I've got a stock 2000 civic, base model/automatic. It runs OK when cold, but after it warms up a bit, under moderate acceleration from a stop, it dies completely for an instant. As soon as the "g forces" drop, it comes back to life. This happens repeatedly until the 80a ignition fuse blows. When it dies, it's complete and utter electrical death, not a sputter. Radio, lights, everything dies. Now, from looking at the wiring diagram, there isn't a lot that will cause the 80a ignition fuse to blow; it's essentially a fuse for the alternator. As such, I've been focusing on that section of wiring for a short, but it all looks good. Alternator is putting out in spec at 14.xV, battery is around 60%.
Here's my question. If there was something like the PCM or ignition switch that was causing the car to turn off and on rapidly like this, would it potentially cause the main fuse to blow from the constant surging? I'm starting to think I'm barking up the wrong tree with the section of wiring that fuse actually works on. Could it be something causing the PCM to die, and the rapid cycling is what's killing the fuse? It's 100% related to g-force under brisk acceleration. If you accelerate slowly, it works fine. Stab the throttle from a stop, it dies. At higher speed you can stomp on it and it works fine also, it's just that initial thrust. I also noticed it on a couple of hard right hand turns.
Has anyone encountered this? I checked to see if it fell under the ignition switch recall, but it didn't apply. Symptoms sound very similar though. I'm going to try disconnecting the the alternator cable and eliminate that as a possibility, but visual inspection looks good. The car did have an aftermarket starter in it that has been long since bypassed (completely unplugged), but all the electrical connections where it was tied in look OK. I just took it to a shop that did 3 hours diagnostics on it and although they could replicate the problem, they had no clue and billed me anyway.
Thanks for any input.

 

Start by disconnecting the alternator cable at the hood fuse box.


What did they charge you?

 

Thanks for the reply. Just my luck, I went out to do a test run with the cable disconnected and I wasn't able to replicate the problem. I'm going for a longer drive tomorrow and taking my tools so I can isolate the cable as soon as it acts up again. When it does it, it does it very consistently and predictably, but on short drives it seems to work until it warms up. The shop charged 3 hours of labour, it was over $200 CDN. I'm not impressed. According to the work order, even after a test drive where they replicated the condition, they went on to check spark plug gaps, vacuum lines and other items that I can't see having anything to do with the problem. They were ready to install some new plugs and sell me a new battery though, even though they admitted it probably wouldn't fix anything.

I should have added to my original post that I was also making the assumption that something grounding out is causing the engine to die, and eventually blow the fuse. I'm second guessing that though, I'm thinking now that even if the main cable were to ground out, it wouldn't cause the entire care to go dead immediately. It's not hard to figure out what is on the circuit for that main ignition fuse, so it's either in that circuit directly, or the fuse is blowing because of the rapid on/off cycling causing some kind of surge. I'm hoping I'll get a chance to isolate the alternator/cable from the equation tomorrow. If it's still stuttering then I'll assume the fuse blowing is a symptom of a surge and is a secondary problem.

On a tangent, I'm not a mechanic, but at 43 I'm going back to school next week to become one. A local dealership conglomerate is paying to send people to school through an intensive, condensed program, then placing them at their dealerships as 2nd year apprentices (if you pass the exam). As such, I'm not an expert, but I've been working on cars since I was 14 and I get frustrated when I feel like people are looking in the entirely wrong place for a problem. Especially when they are billing you for it.

 

Please file a claim at your local small claims court. Ask for return of all your money. The shop ripped you off.

Exactly correct.

It actually would.

Good luck to you.

 

muellersfan thanks for the tips. I wasn't sure if the alternator grounding out would kill the car or not, that's really helpful. I've been driving the car for the last couple days and there is no sign of the problem. I'm guessing that when the mechanic was poking around, they might have nudged something just enough to make the problem disappear. I know it will be back though. I'm going to go back to them and discuss the bill. I've given them a lot of business in the past, and they were never cheap but generally got the job done. I was hoping I would get further into actually finding the problem before disputing the bill, but at this point I'm just going to have to wait for it to come back. Thanks again, you've been very helpful.

 

The car worked normally for about a week. One trip in to work, the battery light was coming on at higher RPM (load or no load), I have no tach. When I started the car to go home from work, the battery light came on immediately. After checking fuses and confirming the alternator wasn't putting out, I replaced the alternator. After removing the main alternator connection boot, it was immediately evident that the metal power steering hose crimp had been rubbing on the crimp end of the main alternator cable, and appeared to be signs of arcing. How the original shop missed this, is beyond me. This was where I suggested they look first. Anyway, after replacing the alternator, the car has continued to work normally. I'll update if anything changes, but I'm hoping the problem is solved.

 

Just an update to close off the thread. The car ran well for a couple weeks after getting it back from the garage, with only a couple instances of the problem occurring under hard acceleration. While driving to work, the alternator failed (stopped charging), so I picked up a new one. I decided to replace it myself since it's an easy enough job and the weather had turned unusually hospitable. While removing the old alternator, after pulling back the rubber boot on the alternator output cable, I could see clearly where the terminal was contacting the metal portion of the power steering hose. As the engine rocked, it was grounding out on the metal line to the rack. I should have caught this myself, but working outside in the weather at time wasn't an option. This was exactly where I told the shop to check. Obviously they touched the cable enough to move it slightly, but didn't pull back the boot. Anyway, I'd call this case closed. I hope this might help someone who encounters the same problem (I did find someone else had this problem after the fact, so it will probably happen again somewhere else). Cheers!