Weak Batteries? Can't figure this one out

[DHFF]

I bought an 01 F250 earlier in the year and havent had much of an issue with it until just a few days ago when one day it started cranking over slower. It got progressively worse over the last few days to where in the morning cold it almost doesnt wanna light off and run. I checked the alternator with it running and its putting out 14.5V at idle which seems normal. I shut the truck off last night and measured the batteries with a Fluke voltmeter and they had 12.99V. I again checked them this morning and they were still at 12.75V after sitting all night, yet it still cranked over way slower than normal. I have also cleaned all the terminals in the last couple days.

My question is, don't all these voltages seem enough to be normal? Do I need to load test the batteries or whats next? I am unsure of where to go and dont really want to drop 300 bucks on batteries if these can get me through a little longer. Any ideas?

 

[hawgdoctor]

Might be time for a starter. Been there done that.

 

[zilla68]

I fought starter issues forever, hell in the cold and only cold, my truck wouldn't quit cranking, to the point there was smoke pouring from under the hood.
It was the starter, changed it out, never had a problem since.
Mine started out as slow cranking, then continuous cranking, even with the key removed and in my pocket while I am running trying to get the damn cables off the batteries!

 

[DHFF]

Might be time for a starter. Been there done that.

What do you mean? I somewhat wondered about that as it doesnt really sound the same as it always has. I wondered if it was just dragging a little. When you say been there done that, what exactly do you mean?

 

[DHFF]

Im sure it has the original starter and Im at 136K right now. The batteries don't really look all that old.

 

[DHFF]

I fought starter issues forever, hell in the cold and only cold, my truck wouldn't quit cranking, to the point there was smoke pouring from under the hood.
It was the starter, changed it out, never had a problem since.
Mine started out as slow cranking, then continuous cranking, even with the key removed and in my pocket while I am running trying to get the damn cables off the batteries!

Whoa I don't like the sound of that, had that happen on a ranger when I was a little younger. I guess I'll look into a new starter first then. I didnt think the batteries seemed that bad.

 

[Freightshaker]

I just had my starter in my 01 rebuilt. Sounded like a dead battery and just couldn't roll over fast enough to fire up truck. Checking electrical resulted in everything ok. Pulled starter (very easy) disassembled it (also easy) had some brushes that were done. Starter only was turning half rpms which sounds like a dead battery. Had local shop rebuild starter and I was good. Just a thought.

 

[mandkole]

When you key the ignition (not start it) what is the voltage at the battery? For an example, I just had an issue where the batts were 11V at the GP relay and 10.6V across. Those same batts had 12.4V with no load. One battery was almost not taking a load on load tester.

At 136K and 10+ years old, the starter is getting tired, so that is something to look at also.

 

[Txwindmiller]

I just had the same problem, slow when turning over.
Replaced batteries this week, starts and runs great
Starts ALOT faster and no coughing when cold.

 

[TERRCO]

When you checked the voltage on the batteries did you disconnect them from each other? You can't check batteries unless there separated. You will have two different readings when done disconnected. One dead battery could give you the symptom you described. A dragging started would be my second guess .

 

[DHFF]

When you checked the voltage on the batteries did you disconnect them from each other? You can't check batteries unless there separated. You will have two different readings when done disconnected. One dead battery could give you the symptom you described. A dragging started would be my second guess .

I didnt check them in the morning with them disconnected from each other I guess that was a mistake. I will try that before I buy a starter. What about the cables? Is there a way to check if they are bad? Checking resistance?

 

[ToMang07]

I didnt check them in the morning with them disconnected from each other I guess that was a mistake. I will try that before I buy a starter. What about the cables? Is there a way to check if they are bad? Checking resistance?

Yes...but I'm retarded with electronics, and I can't remember the resistance (Ohms IIRC) you're looking for.

My bet is you have a dead battery/cell as well. I'd pull them and load test them. Pretty much any auto store will do it for free. I had that issue as well, one dead cell and old batteries....it would crank all day and wouldn't start.

Did you ever test the voltage while cranking? You're looking for 10.5+ volts wile cranking IIRC.

 

[DHFF]

Yes...but I'm retarded with electronics, and I can't remember the resistance (Ohms IIRC) you're looking for.

My bet is you have a dead battery/cell as well. I'd pull them and load test them. Pretty much any auto store will do it for free. I had that issue as well, one dead cell and old batteries....it would crank all day and wouldn't start.

Did you ever test the voltage while cranking? You're looking for 10.5+ volts wile cranking IIRC.

THATS what I'm looking for I was looking for that kind of info on cranking voltage I guess. I shouldnt even need to pull them to load test if that voltage is low. Thanks man!!!!!!! I'll see what I can find.

 

[4.0l sahara]

Before you replace the starter I would check voltage drop across the starter cables and grounds while cranking just to be sure it is not high resistance in a wire. That is assuming the batts are good and past a load test.

 

[4.0l sahara]

To do a voltage drop you put the leads to the dvom on each end of the cable and while cranking the voltage displayed is how much is being lost to the wire due to resistance.

 

[DHFF]

AND they cranked at about 11V. Hmmmm. Its weird because sometimes it cranks and fires somewhat normal and other times it cranks slower and longer.

 

[DHFF]

To do a voltage drop you put the leads to the dvom on each end of the cable and while cranking the voltage displayed is how much is being lost to the wire due to resistance.

Ok I will do that also. I'm sure if thats the issue it will show as a larger voltage drop which is higher resistance. We'll see. Thanks for the help.

 

[Freightshaker]

AND they cranked at about 11V. Hmmmm. Its weird because sometimes it cranks and fires somewhat normal and other times it cranks slower and longer.

That kind of sounds how mine went out. It would slow crank for a bit then like you hit a switch it would crank at proper speed and start.

 

[Southmike]

Mine cranks like pooh when it is cold and I only get4-5 tries..
I blame mine on a failing icp, old azz glow plugs and one weak battery.
plus my main battery cable is looking rather gnawed on from jumping.
debating about making my own 3/0 cable or buying an oem.

fires right up when it is warm...

I need to do some wrenching. That rules out the starter on mine I think.
might want to check some of those first.