TCCoA Forums banner
1 - 11 of 11 Posts

·
Registered
Joined
·
694 Posts
Discussion Starter · #1 ·
I noticed when I pulled into my driveway that my Voltage meter was sitting really low... almost at 8 volts (whatever the unit is). My headlights were really dim, my wipers were running slow, and the heat wasnt as powerful. Normally I have seen my volt meter go down a little from the A/C clutch engaging and what not, from having the heater on, but goes back to normal after a couple seconds. This went on for a couple minutes before I turned everything off (wipers, heater, headlights) before it climbed back to normal. Revving it didnt help (thought maybe the RPMs were low and the altenator wasnt getting enough charge). It climbed back up on its own. Sound like a bad altenator or battery? Definetly didnt seem like a normal thing. Thanks.
 

·
Registered
Joined
·
694 Posts
Discussion Starter · #2 ·
Also, sometimes when I turn really sharp the power steering seems to draw more power from the car. This was after I turned into my driveway at a sharp turn (steering wheel cranked all the way). Maybe related to that? I dunno. It has never affected it before though.
 

·
Registered
Joined
·
414 Posts
My guess is alternator.
If you have the engine running and the battery is bad the voltage would still be high as the alternator is charging.

Bad batteries usually show their ugly face after trying to start the car in very cold weather or you realized it's to weak to start the car after leaving the lights on for just a few minutes.

Yesterday I was working on my shifter and had left my interior lights on. They were on for 15 hours. Car had no problems starting up while it was -5 deg C out. I trust my battery is ok.

Lucky for you 4.6L alternators are very easy to change.
 

·
Registered
Joined
·
694 Posts
Discussion Starter · #4 ·
Yea, well the altenator on it is factory. I got 116k on it right now. I'll see how it does today. The battery is getting a little weak from the cold starts... cranks a little slower then normal... but nothing severe. Thanks.
 

·
Registered
Joined
·
9,966 Posts
Yea, well the altenator on it is factory. I got 116k on it right now. I'll see how it does today. The battery is getting a little weak from the cold starts... cranks a little slower then normal... but nothing severe. Thanks.

make sure you have the autoparts store charge that battery or you will have draw issues with the new alternator..if you can get them to charge it or the old alternator caused excessive battery draw, it probably killed cell in the battery, rendering it to boat anchor status.
 

·
Registered
Joined
·
680 Posts
I have been having the same issue. My alternator never puts over 14 volts unless its cold outside. My belt is newer, my alternator is new, I have upgraded my grounds and power wire, and my tensioner is showing that the belt is not stretched. Does anyone have any ideas? When its gets hot, at idle it is below 12 volts...

- Stephen

Edit: forgot to mention that the regulator is new as well and the #11 fuse is good.
 

·
Super Moderator
Joined
·
12,733 Posts
To check any battery:

There is a pretty easy way to do it. It involves letting it sit to equalize charge on the plates for a time, then measuring the voltage on it.

This link talks about the voltage on the terminals as an indicator of battery charge:
http://www.batteryuniversity.com/partone-13.htm
Basically, you disconnect it overnight, then measure it with a meter in the morning, and if it's below 12V, try to charge it. Then leave it again overnight. If it is still below 12V, it's shot. (If it is below 10V, after sitting for a while, it probably has a dead cell.)

Here is more info than anyone ever wanted to know about batteries:
http://en.wikipedia.org/wiki/Lead-acid_battery

Check the links for more info.

And for the colored-top bling crowd there's this:
http://en.wikipedia.org/wiki/Absorbed_Glass_Mat

The reason I don't like those batteries is the cost over time...If funds are unlimited for you, YMMV...

"Valve activation allows some of the active material to escape thus decreasing the overall capacity of the battery"​

Like any 'sealed' battery, they eventually lose electrolyte, and die early; just about the time the warranty expires. I still have the original motorcraft battery in the Black Cougar. But it won't operate upside down...


To the original issue: The alternator will load the engine like the steering pump if the battery terminal/wire grounds out; it's a few horsepower load on the engine.
That could be both issues...or you could have hit the rubber stop turning in; that causes a big load.
 

·
Registered
Joined
·
1,278 Posts
When ever I check an altenator I disconect the battery when the car is running. Then I crank on the AC, sterio, and turn the sterring wheel. If the car dies then the alt is bad.
 

·
Registered
Joined
·
3,726 Posts
I wouldn't use the disconnect from battery test for an alternator.

Can you charge the battery? If so make sure it gets to 12.7/12.6 volts. If you can charge it to that voltage, then with the engine off, turn on the headlights for a minute. Make sure you still have over 12 volts, should be closer to 12.5 volts.

Also check it after car sits for 8/10 hours and if it is significantly lower you have something drawing power and need to find out what it is.

Check the voltage of the battery at the battery posts and where it connects to the alternator, those should be the same.

Now, with the car running, check the voltage at the battery. should be around 14.3 volts. Check the drop between the alternator and the positive battery. Should be nearly 0 volts. With the volt meter still on the battery and ground, rev up the car and see if it drops or goes significantly higher. If it drops it can be a bad regulator or belt, you can check for belt slippage.

The car under 99% of the situations while running should be running off the voltage provided from the alternator, the battery is for storage and when the engine is off.
 
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top