I’ll take it to a mechanic if it persists, but I’m not very knowledgable about cars and would like to have a basic idea of what I’m dealing with.
I was happily driving along listening to the radio, when suddenly it start going ‘WHOOMP-WHOOMP-WHOOMP’ about 5 times a second. Some sort of stacco bass sound.
I noticed the clock started switching between the time and the radio station - and it seems that the radio was turning on/off 5 times a second. The time/station change corresponded to the ‘whoomp’, and the whoomp is the sound it makes when you turn the radio on.
So I pull into my parking lot and notice my lights have gotten a lot dimmer, both internal and the headlights. I tried turning off the headlights, and my stereo stabalized - at least the clock stopped flicking, I had the volume turned down by then. I tried the wiper blades, and they were really sluggish, so it seems to be an across-the-board electrical drain of some sort.
So, it seems like someone replaced my alternator with a 9v battery, or something. Any idea what might be wrong or what I could check/do about it?
From my Brother-In-Law.
He suggests it’s a negative earth.
Check the earthing line (located in the engine bay under the car) to make sure it is bolted to the chasis rail. If that’s loose, tighten it up.
He seems to think this is right as he’s experienced this problem before when it comes loose it does exactly what you described.
The possibilities include a faulty charging system (alternator, wiring and connections to it, etc.), faulty battery, and faulty battery cable connections (including both positive and negative [ground/earth] cables and branches thereof). The problem area may be fairly obvious/easy to find, or may take some detective work to pinpoint.
It’s an 88 grand am - battery is only 2 or 3 years old, so I don’t think that’s crapping out.
Update:
I went around and drove it a bit this morning to see if the problems persisted. It started right up, so the battery was charged. I noticed that the seat belt warning tone signalled too fast, compared to normal, and my turn signals were a lot slower. I remembered that’s a sign that a light burnt out, so I checked. Indeed, my front right blinker is out. Is that related in any way? The fact that the blinkers started getting whacky/slow at the same time this problem cropped up suggests it, but I can’t imagine a burnt out light bulb creating those issues.
In any case, I had to let someone borrow my car today, and it wouldn’t start for them when they got to their destination. They had to jump it, get back here, and the battery is dead again. Which suggests the alternator wasn’t properly charging the battery, I assume.
Is there anything I can do to definitively check if it’s the alternator? If it is, is it fairly easy to replace on your own? I’m not too familiar with cars, but I’m not totallly mechanically incompetant.
Simplest check is to get a a VOM and see what the battery is showing volt wise with no cables attached, Then with cables attached, Then start the car and see what voltage is at idle and have someone slowly advance the throttle and see if the voltage goes up to just over 14 volts. Then have them start adding load, = lights, radio, heater fan and see if the alternator can carry it all. See if the voltage gets all jumpy.
Do easy and cheap first. Check both ends of the ground cable and then the positive cable. Make sure all wires going to the alternator are connected. Make sure the belt driving the alternator is not slipping. Etc.
Depending on what you find will determine which area to start throwing money at.
I suspect lose wiring, intermittent short, bad voltage regulator, bad alternator in that order.
YMMV
PS, 2 years is plenty to expect from most batteries ( really cheapies now days unless you bought a really good one. ) so don’t assume it is good. Newer cars are electrically heavy and hard on batteries…
Looks like AutoZone has a free alternator/battery/regulator test. I think I’m going to look into that tomorrow. I guess I can yank my battery up there, have them test it and charge it (also free), if it works, bring it home, pop it in, and use it drive up there to test the rest of it.
usually, a smallish wrench, in the neighborhood of 8-10mm to loosen the terminals. Perhaps a broad flatblade screwdriver to spread the terminals and release their grip on the battery posts. (Twist between the two sides at the bolt end)
Remove the negative cable first.
Once the cables are off, it’s usually just two nuts to be undone to free the battery. Some hold-downs are a plate or bar across the top of the battery, and some are way down at the bottom of the battery, holding onto notches/flanges at the battery’s base. Happily, the top-mounts are more common and easier to deal with.
Before you put it back in (assuming it tests OK) clean the terminals with either a battery terminal cleaner or some medium-grit sandpaper. Also, clean off the top of the battery - flushing with water’s about all you really need. Just get the dirt off as dirt is surprisingly conductive and will drain a battery. If the cables are funky, replace them. They’re generally around $10-15 each.
Oh… before you go yanking anything out, call your AutoZone and see if you need to do anything of the sort. They probably have a portable tester that they’ll just wheel out to your car in the parking lot and do the tests with everything in place.
Yeah, I might just take the whole car there - but it’s dead at the moment and I’m worrying it’ll die on the way there if I jump it. I guess I can charge it for a half hour - that should be enough to give me the power to go 5 or so miles.
When I buy a battery I ask the store clerk to test the alternator/old battery & they do it for free. This is a regular auto parts store. Could be untight battery connections too. How old is that battery?
If you can jump the battery and it will run for a while but eventually dies and you need to jump it again, its definately the alternator that’s shot. If you keep running the battery down you can kill it too, so don’t be too surprised if you have to buy a new battery when all is said and done also.
Well, I was thinking it might be a dying battery that can’t hold a charge, too.
Question - more for my curiosity than anything - when you’re driving the car, running the various electrical components, are they being run off the battery, which in turn is being charged by the alternator, or just run directly off the alternator?
Hard to say, probably a bit of both. A car will run strictly on the battery if the alternator is not working. And most cars can, after starting, run with just the alternator if the battery is taken out of the circuit–though it’s not wise to try this, as it can and often does fry the alternator and other electronic components (e.g. the computer).
Got the battery charged and tested - the guy there said it was fine, but I’m not sure if he knew what he was doing. The full charge idle voltage (I assume it was idle… it was just hooked up to the diagnostic machine, not bearing any load) was 11.5-11.6. Is that normal?
Looks like it’s the alternator, but I’m going to drive up there to double check. I have a fully charged battery - and I should be fine driving on that, right? It’s a 10 mile round trip. No radio, etc. of course.
