This just started.... or at least I just noticed it. With the headlights on dim and engine warmed up and idling, the brightness cycles from normal to slightly dim. Cycle time is around a second. When I rev the engine slightly, they return to normal steady brightness.
When running with or without lights, the ammeter is just right of center, slightly charging, in the normal position.
I don't suspect a connection -- within the last 2 months, I removed and cleaned all the battery connections, including regulator and other parts when I was fixing a grounding issue.
Battery cranks start just fine. No other indications of failing battery.
On Tuesday, August 4, 2015 at 7:39:00 PM UTC-4, Snuffy Hub Cap McKinney wro te:
s on dim and engine warmed up and idling, the brightness cycles from normal to slightly dim. Cycle time is around a second. When I rev the engine sl ightly, they return to normal steady brightness.
slightly charging, in the normal position.
leaned all the battery connections, including regulator and other parts whe n I was fixing a grounding issue.
check battery voltage with vehicle running at idle. it must be 13.8 volts
That is DEFINITELY not the issue, as the alternator is a (generally anyway) 12 pole 3 phase devive, and is geares about 2:1 from the crank, so at 500RPM idle would be turning about 1000RPM, making about
60Hz power (if my math is anywhere close to correct) so any cycling would be in the 1/60th second range -a very high frequency flicker, not a surge with a 1 second period.
You can be about 90%+ shure the alternator will need replacing within a month or so, and the unsteady lights at idle will go away when the alternator is replaced. How many miles are on this beasty, and how old?? Is it the old Aeroscare?
I had the same problem on my '89 - replaced the regulator - no joy. Replaced the alternator - problem fixed.. I managed to pick up a good recently replaced rebuild at the wreckers for $30 (about 20 years ago)
headlights on dim and engine warmed up and idling, the brightness cycles from normal to slightly dim. Cycle time is around a second. When I rev the engine slightly, they return to normal steady brightness.
center, slightly charging, in the normal position.
and cleaned all the battery connections, including regulator and other parts when I was fixing a grounding issue.
RPM is steady. Oscillating lights happens at slow idle. If I increase idle speed just a little with accelerator, lights are steady.
You can check to see if it is working - but it can be working and still "surge". A good analog voltmeter connected to the output of the alternator will show if the voltage is fluctuating.
Even at steady RPM, the reguator relay goes in and out, but I really don't know at what rates. IIRC a generator needs a regulator with 3 relays, and an alternator needs 2 relays.
One of the two limits how much current goes to the field winding, but is that only for generators?
Do you have a wife with another car. I always wanted a wife with a pickup truck, but I coudlnt' find one. What's the worst that can happen, youll break down onthe way to work adn she'll have to pick you up and take you to work and the car will sit there until you can get a new alternator. Can you get one right away and replace it wherever the car dies, or would you have to be towed?
What's the voltage of the alternator, while the lights oscillate. While they say 13.6 is what it should put out, and maybe lightbulbs are designed for that voltage, really anything over 12 6 should charge the battery a little. Or say over 12.7. You said your ammeter shows slight charging. If the alternator will to completely fail, you could drive more than a day I'll bet if you have a fully charged battery. Old cars start easily and cars don't need too much current to run.
I once drove from NYC to Chicago to Indianposlis to the Pa. Turnpike near Pittsburgh. When I left NY, maybe by the time I got to Ohio or earlier, the headlights were dim, but as I usually do, I igonred the problem. The rest of the car ran well and most of my driving was in the day time.**. I drove to Chicago and around there for 2 or 3 days, Indy for a couple day, and just as I got to the big gas station near the entirance to the Pa. Turnpike (after a trip of 1400+ miles.) the car stalled and woudn't start. I opened the hood and the fan belt that drove the alternatas literally hanging on by a thread. Of course a fanbelt thread is thicker than sewing thread, maybe half a millimeter.
But the belt was no longer tight enugh to drive the alternator and I had been running on the battery for at least a couple hundred miles, and that was in the dark and again I'd noticed that the headlights weren't very bright. But the road had been well marked and I coudl follow the car in front of me, etc. . IIRC, I had a fan belt in my trunk, that I had taken from a junk yard car like mine, and I put that on, and after I got some food I got the gas station guy to come the 100 feet to my car with his portable jumping thing, and I'm not even sure he charged me, but he started me and I started driving east and charging the battery. And that was the end of the story.
Now I was in my 20's and people our age don't live like this, but otoh, if I were just drivign around town, and I had someone to come and get me, even the number of a taxi-company. I'd still do it that way. Because you don't yet know that the alternator is bad or that you'll
*have* to replace it before the car fails permanently for some other reason.
In the old days the oil light would flicker on and off at idle and that was normal, even though it's a lot more imporant that a few little light bulbs.
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