Intermittently the car will lose all power when key is turned to ignition

TEESURRATT

MEMBER
2000 HONDA ACCORD
3.0L
V6
2WD
AUTOMATIC
290,150 MILES

On some occasions, when I turn the key to position III, where the engine cranks, the car loses all power like the battery is drained. I can turn on the car, however, by popping the hood and jiggling the battery cables, and cranking it again. This will work for several weeks and then happen again for me to do the quick fix. When this started happening several times a week, I cleaned the terminals of the battery and the battery cables as well, and the problem went away for about a month and a half. This isn't a major inconvenience, but I would like to not have to deal with this every couple of weeks.

1 Reply

CARADIODOC

MECHANIC
33,871 POSTS

Since you already looked at the best suspect, the battery cable clamps, the best approach now is to find the exact location of the bad connection. The way to do that is when the problem occurs, be careful to not disturb anything. We want it to stay in the defective condition so there's a defect to be found. Turn the head lights on so current continues trying to flow. That can help to keep it in the bad state, plus, that causes a voltage drop to occur across the bad connection. That is what we're going to look for.

Use a digital voltmeter for these tests. Everyone has their own favorite places to start. Mine is to check each connection individually, starting with the positive post. Place one meter probe on the battery's post, and the other probe on the clamp on that post. Those are supposed to be the same point in the circuit, so the voltage is supposed to be the same on the clamp and on the post. The difference is supposed to be 0 volts. Set the voltmeter to one of its lowest ranges, then see what you find for voltage. Anything over 0.2 volts is too much, but when the symptom is this bad, if that is the bad connection, you'll find close to 12 volts. That would be the clamp to clean / tighten / repair.

Now take the same reading on the negative post and that cable clamp. Again, the most that's allowed is 0.2 volts.

The next best suspect is where the smaller battery positive wire bolts to the under-hood fuse box. Place one probe on that terminal, and the other probe on the tip of the stud that terminal is bolted to. If you find any voltage there, you'll usually also find the electrical system comes back to life when you twist that terminal. The fix is to just tighten that nut unless the terminal looks dirty or corroded, then clean it too.

The last thing is where the smaller negative battery wire bolts to the body. Those connections can become rusty or the terminal can corrode apart. Identify that by placing one meter probe on the negative cable clamp, and the other one on a paint-free point on the body sheet metal or a rust-free bolt head on the body. This wire should be the last suspect due to your observation the electrical system will start working again later. When the smaller negative wire rusts apart, it rarely starts working again on its own.

If you need it, here's a link to an article on using a digital voltmeter:

https://www.2carpros.com/articles/how-to-use-a-voltmeter