old97civic

Well, I had an interesting event the other day. Was away for a week and the Civic sat undriven for about that time or maybe a day longer. Anyway after coming back I drove on Thurs but just went to nearby grocery stores and came back. It didn't show any signs of struggling when I started it. Then yesterday (Sat) I drove it again to a nearby store, that went fine. Then when I went to leave, I turned the key and heard kind of a muffled pop sound when the key was turned all the way and got nothing. Everything went dark, no crank, nothing. I gave it a few minutes and tried again. Got the dash lights, could hear the fuel pump running, then whenever I tried to turn the engine over everything went dark again. I heard rapid ticking from the glove box area so I started thinking main relay.

But I figured I'd try the obvious which is the battery is weak and got a boost, started up right away. Went on the highway to hopefully charge it. Haven't driven it since, but parked it so I can boost it easily if I need to.

History on the battery: I checked my paperwork on it and I got it pretty much exactly 9 years ago, so likely due for replacement in any case. I'm pricing out batteries at the moment.

The thing that was different though was when I turned the car off there was again a muffled pop sound, kind of like what you hear out of speakers/audio. Any idea what that is pointing to?

ezone

There's a bad connection somewhere between the battery and where the cables attach to the rest of the car.

310civicEX

i would assume the pop was a backfire into the airbox.. due to missfire ... something in the harness.. obd2 would probably have some clues

old97civic

Well there was a lot of green/blue stuff on the negative terminal of the battery, but the other end of the ground cable looked ok. So I will start by cleaning off all that stuff. I will check the positive harness as well and plug in my OBD2 scanner and check for any hints there.

ezone

Good chance your problem is in that.

Make it act up (car goes electrically dead) and leave the key on, then jump out and feel that connection for heat (clue) and give it a wiggle and see if the car powers up.

Any engine and trans codes are erased when the PCM lost battery power, so don't expect to find much there unless it' got an active fault.

old97civic

Update - cleaned the battery negative terminal. Went to start it but got nothing, same as on Saturday. Just the clicking from glove box area.

Since I was able to drive the car on Sat (after boosting), I assumed under dash fuse 15 would be fine, but just to be pedantic I checked it. (It was fine)

I checked the positive cable, there's a bit of the blue/green stuff at the battery terminal but not much. All connections were tight. I checked the positive cable at the under hood fuse box, looks brand new, no signs of corrosion there. Bit harder to look at the alternator but I will try that later today.

Voltage on the battery is 12.2 (engine off), so definitely lower than expected. I will boost it again tonight and check for alternator output.

ezone

How did you clean it?

Electrical connections need to have fresh clean shiny metal exposed between all contacting areas so they can have good electrical flow.

goggle surch for battery post cleaner

old97civic

Didn't want to bog down the post with those details, but yeah I used one of those 2-in-1 brushes as in your pic after removing the fluffy stuff with hot water + baking soda. Wiped everything clean before before putting it all back together.

What I'm going to do is boost it, check to see if I'm getting good voltage from the alternator, then go for a long drive to see if I can charge it now that I've cleaned it, then see if I can start it on its own.

Update: ok so I checked the alternator B terminal, it's fine in fact it looks brand new, no corrosion whatsoever. Checked and got continuity between B terminal and the positive battery post.

Also checked all the big fuses in the under hood fuse box, everything was good there.

Now, backpedaling a bit, the other day I thought the ground cable from the battery goes to the thermostat housing (was a bit dark) but that's a different ground cable. The one that comes off the negative battery post doesn't go far, it bolts to the body just a few inches in front of the battery. The bolt head looks rusty but I checked continuity between the battery post and the ground at the thermostat and got 0.3 ohms. Not sure at what point I should try to loosen (and possibly break) that bolt, lol. Anyway, for now just waiting for the boost car aka my wife to come back.

old97civic

Ok so I boosted it and measured battery voltage with the engine running. Getting around 14.5V. I had someone turn loads on and off, voltage would fluctuate slightly, ie .05 or 0.1 V and then return to normal. So the alternator sure seems to be working fine.

Then, I went to back it up onto the driveway and it quit on me when I was right in the middle of the street Battery is totally dead, couldn't even power the hazard lights ... anyway... boosted it again and got it onto the driveway. Strange that it quit like that. I managed to reverse onto the driveway on Saturday, but it was daytime on that occasion, whereas today it was around sunset and I had the headlights on (I turned the headlights off before I reversed the second time just to be sure).

So a transmission shift (power for solenoids?) + headlights = too much for the alternator?

ezone

The ground wires at the thermostat are the ones the computer needs to operate and to control just about everything on the engine and transmission. And the main relay. It's pretty dang important.

DO IT. Actually, test it first....under a load.

If you take it apart and it goes to hell, aren't there a couple other places the ground cable can be bolted near that one?

Don't forget about the rest of the ground cables that attach between the engine/trans and the body.



An ohm test on a circuit that has to carry high amperage is all but worthless. A single strand of wire can ohm check great but open up when you try to pass 150+ amps through it.

You need to be checking for voltage drop while it's under the loads it sees during cranking.
google 'voltage drop test' for more.
Did you use the voltmeter to check the battery POSTS at that time? Not the cable clamps, but the round posts of the battery itself.

The battery can be fine and have plenty of available voltage, yet a cable clamp can have a bad connection that causes the car to go dead. Or bad connection between the cable and its clamp. Or literally anywhere between the battery (the power source) and the rest of the car (the load)

The battery can also have an internal bad connection, if that happens there would be low/no voltage when you measure ON THE POSTS.


Read this thread for test light tips (tests while the car is electrically dead): https://www.civicforums.com/forums/217-mechanical-problems-vehicle-issues-fix-forum/370995-99-civic-no-crank-no-start.html

old97civic

Ok thanks more things to check.

As for where I was stabbing the probes, getting the car off the road with a sense of urgency makes my memory a bit foggy about the measurements taken during the previous boost but AFAIK I was putting the probe ends where the clamps meet the posts, as it gives a spot for the tips to stay without slipping. So yeah in that case it's not measuring the battery alone.

Given that Colin couldn't boost because of where the weak spot was in his +ve cable, and I CAN boost, is it more likely I have a bad ground? Going to go check them.

ezone

The jumper cables were able to supply the needed power to start the car, but your battery could not.
Therefore: Logic says if you have a bad connection it will be somewhere between your battery and wherever you placed the jumper cables.

old97civic

Or the battery could indeed be dead. Which, after getting it tested, was the case for me. So new battery...

I went through the cables, ended up replacing the ground on the transmission housing and the ground on the power steering bracket.

sdaidoji

iTrader: (1)

weird stuff happens with dead batteries....

i went through a lot of stuff only to end with a dead battery - do it forst, especially if it is at 9 years old