Random Voltage Dropouts
09-04-2007, 05:52 AM
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Random Voltage Dropouts
The car is a 1999 Civic LX sedan.. I just worked on this car all day yesterday to try and find the source of the problem but I couldn't exactly find any clues.
On my aunt's and uncle's way back from their trip the car just didn't want to start up on them, they were able to get a jump and be on their way, only for the same thing to happen again the next time they stopped. The car wanted to die every time they were coming to a stop now, which only made it harder to drive.
When they brought it back I tried checking things out systematically, pulling fuses one by one and checking the system.. couldn't find a thing. The car doesn't drain the battery or have voltage dropouts when you just let it sit without the key in the ignition, but once put in the key and turn it into IGN I or II, the dropouts are present. The battery would have about 12.9V or power, then drop out either completely or down to 9V randomly. It could be either every several minutes or few seconds. If you were to use pretty much any electronic device in the car (power door locks, brake lamps, headlights, etc.), all power would pretty much disappear then come back.
I've tried isolating the starter by disconnecting the positive battery wire to it to see if there was a short in that itself, still was acting up. All the ground cables checked out, body ground was getting full signal.
When you try to fiddle around with the key in the ignition and switch it from IGN II to IGN I the dash lamps would seem pretty dim most of the time, and you can hear either the fuel pump or some motor in the engine bay actuated by the PGM FI main relay moving pretty slowly, but sometimes when switching the key back and forth, the car all of a sudden has full voltage and I can hear the motor running at full speed, but if I touch anything else it will drop out or it will just drop out on its own.
The only thing I can think of that might be related to this is when the car was run off of the road about half a year ago, car's right front wheel was bent, had to have that replaced and nothing else seemed to be damaged. There was a noise when turning with the car in probably either direction, but we couldn't find out what it was, and the noise could have been there all along, I don't know. I tried looking at all the harnesses for visible damage but to no avail.
The car cannot start itself at all, you either just hear the click of the starter or nothing at all, but if you try to jump it with a running car, it will just barely crank and finally turn over, and it almost seems to run just fine, can't tell if the voltage drops are actually still there but before I got to the car it was having the dropouts when actually driving.
We're taking the car to a mechanic today to hopefully find the source of this problem, anyone have ANY idea what this could be??
Edit: the car also throws no CEL's
Modified by Prelude Gundam at 3:11 PM 9/4/2007
On my aunt's and uncle's way back from their trip the car just didn't want to start up on them, they were able to get a jump and be on their way, only for the same thing to happen again the next time they stopped. The car wanted to die every time they were coming to a stop now, which only made it harder to drive.
When they brought it back I tried checking things out systematically, pulling fuses one by one and checking the system.. couldn't find a thing. The car doesn't drain the battery or have voltage dropouts when you just let it sit without the key in the ignition, but once put in the key and turn it into IGN I or II, the dropouts are present. The battery would have about 12.9V or power, then drop out either completely or down to 9V randomly. It could be either every several minutes or few seconds. If you were to use pretty much any electronic device in the car (power door locks, brake lamps, headlights, etc.), all power would pretty much disappear then come back.
I've tried isolating the starter by disconnecting the positive battery wire to it to see if there was a short in that itself, still was acting up. All the ground cables checked out, body ground was getting full signal.
When you try to fiddle around with the key in the ignition and switch it from IGN II to IGN I the dash lamps would seem pretty dim most of the time, and you can hear either the fuel pump or some motor in the engine bay actuated by the PGM FI main relay moving pretty slowly, but sometimes when switching the key back and forth, the car all of a sudden has full voltage and I can hear the motor running at full speed, but if I touch anything else it will drop out or it will just drop out on its own.
The only thing I can think of that might be related to this is when the car was run off of the road about half a year ago, car's right front wheel was bent, had to have that replaced and nothing else seemed to be damaged. There was a noise when turning with the car in probably either direction, but we couldn't find out what it was, and the noise could have been there all along, I don't know. I tried looking at all the harnesses for visible damage but to no avail.
The car cannot start itself at all, you either just hear the click of the starter or nothing at all, but if you try to jump it with a running car, it will just barely crank and finally turn over, and it almost seems to run just fine, can't tell if the voltage drops are actually still there but before I got to the car it was having the dropouts when actually driving.
We're taking the car to a mechanic today to hopefully find the source of this problem, anyone have ANY idea what this could be??
Edit: the car also throws no CEL's
Modified by Prelude Gundam at 3:11 PM 9/4/2007
09-04-2007, 06:00 AM
#2
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Re: Random Voltage Dropouts (Prelude Gundam)
Have the batt. checked. Could just be that the batt isnt holding a charge completely. Also jump the car and read the voltage off the post that the thick white wire is attached to on the alt. Should read in the 14s. Follow that wire to the fuse box, should read 14, then do the wire next to it. Should be the same. IF ITS NOT then check your 80A fuse thats in that fuse box.
If the alt. isnt giving off the 14v's then you could have a bad alt. No reason to take it to a mechanic if you have basic tools and a volt meter.
If the alt. isnt giving off the 14v's then you could have a bad alt. No reason to take it to a mechanic if you have basic tools and a volt meter.
09-04-2007, 06:09 AM
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Re: Random Voltage Dropouts (Luserkid)
I already used a voltmeter. Like I said, the battery was giving out a full 12.9V when trying out the car, all power is making it through to both sides of the main fuses in the fuse box as well as the cable leading to the alternator.
The alternator seems fine, not getting a battery light at all when the car ran. I was unable to check for voltage while the car was running due to the fear of the car just dying before I got it in the garage to work on, and I couldn't keep it running inside, but the battery shows that it is still giving a strong signal as long as the key isn't turned in the car.
The alternator seems fine, not getting a battery light at all when the car ran. I was unable to check for voltage while the car was running due to the fear of the car just dying before I got it in the garage to work on, and I couldn't keep it running inside, but the battery shows that it is still giving a strong signal as long as the key isn't turned in the car.
09-04-2007, 06:11 AM
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Re: Random Voltage Dropouts (Prelude Gundam)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Luserkid »</TD></TR><TR><TD CLASS="quote">
If the alt. isnt giving off the 14v's then you could have a bad alt. </TD></TR></TABLE>
If the alt. isnt giving off the 14v's then you could have a bad alt. </TD></TR></TABLE>
09-04-2007, 06:19 AM
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Re: Random Voltage Dropouts (Probot)
Your batt. might have the 12.9 but obviously when a load is on it thats not the voltage that it can hold. You either have a dead batt or your alt isnt doing its job. Take both of them to your local autozone/kragen and have them tested. Its free and no need for the car.
09-04-2007, 11:31 AM
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So even though the battery will be putting out 12.9V, there's cases where it won't even be able to hold it when just a couple of things are on?
What kind of damage would this battery have? I was told that the battery was replaced recently too.
What kind of damage would this battery have? I was told that the battery was replaced recently too.
09-04-2007, 11:42 AM
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Re: (Prelude Gundam)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Prelude Gundam »</TD></TR><TR><TD CLASS="quote">So even though the battery will be putting out 12.9V, there's cases where it won't even be able to hold it when just a couple of things are on?
What kind of damage would this battery have? I was told that the battery was replaced recently too.</TD></TR></TABLE>
yes, think of a AA battery in your CD player or something, even though disconnected the terminal voltage reads 1.5 volts, if the battery is bad/dead as soon as a load is placed on it the voltage would drop significantly. Same thing in your car battery. Measure the voltage at idle iwth nothing on, have a friend turn some stuff on in your car, lights, AC, stereo, iwndows, then measure the voltage on the batt.
The positive plates may be corroded, you will be able to tell by checking the outside of the battery for bubbles/swelling. Any autozone will do a capacity test for free on your battery and an alternator service test as well. Good luck
What kind of damage would this battery have? I was told that the battery was replaced recently too.</TD></TR></TABLE>
yes, think of a AA battery in your CD player or something, even though disconnected the terminal voltage reads 1.5 volts, if the battery is bad/dead as soon as a load is placed on it the voltage would drop significantly. Same thing in your car battery. Measure the voltage at idle iwth nothing on, have a friend turn some stuff on in your car, lights, AC, stereo, iwndows, then measure the voltage on the batt.
The positive plates may be corroded, you will be able to tell by checking the outside of the battery for bubbles/swelling. Any autozone will do a capacity test for free on your battery and an alternator service test as well. Good luck
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09-04-2007, 12:54 PM
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Re: (slowSOHCvtec)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowSOHCvtec »</TD></TR><TR><TD CLASS="quote">
yes, think of a AA battery in your CD player or something, even though disconnected the terminal voltage reads 1.5 volts, if the battery is bad/dead as soon as a load is placed on it the voltage would drop significantly. Same thing in your car battery. Measure the voltage at idle iwth nothing on, have a friend turn some stuff on in your car, lights, AC, stereo, iwndows, then measure the voltage on the batt.
The positive plates may be corroded, you will be able to tell by checking the outside of the battery for bubbles/swelling. Any autozone will do a capacity test for free on your battery and an alternator service test as well. Good luck </TD></TR></TABLE>
It turns out it was the battery.. But what kind of confused me was that while I just left the car in run or just ACC and watched the battery voltage, it would sit at either 9V or at 12V and randomly drop to 9V while I was outside of the car watching it, touching nothing.
Boy did I screw up this time.
yes, think of a AA battery in your CD player or something, even though disconnected the terminal voltage reads 1.5 volts, if the battery is bad/dead as soon as a load is placed on it the voltage would drop significantly. Same thing in your car battery. Measure the voltage at idle iwth nothing on, have a friend turn some stuff on in your car, lights, AC, stereo, iwndows, then measure the voltage on the batt.
The positive plates may be corroded, you will be able to tell by checking the outside of the battery for bubbles/swelling. Any autozone will do a capacity test for free on your battery and an alternator service test as well. Good luck
</TD></TR></TABLE>It turns out it was the battery.. But what kind of confused me was that while I just left the car in run or just ACC and watched the battery voltage, it would sit at either 9V or at 12V and randomly drop to 9V while I was outside of the car watching it, touching nothing.
Boy did I screw up this time.
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