Two bad batteries in a week
FTE Legend
Joined: Jul 2010
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From: Northeast, OK
To determine which to replace first, but only after cleaning ALL of the connections and inspecting the cables, you need to put a voltmeter on the battery after the truck has been driven or run for a few minutes to recharge the battery from starting, and while the truck is still running. At that point the battery voltage should be above 14.0 and preferably at 14.4. If not, the alternator and regulator are suspect. In my experience it is preferable to replace both at the same time as it is difficult to determine which is bad, and either of them going bad can ruin the other.
But if battery voltage is at 14.4 after the truck has been driven and is still running and you still have a starting problem then you either have a bad battery or a bad starter - assuming the timing isn't too far advanced and the cables are good. So, if you think the battery has to be good because it is new, replace the starter at that point.
But if battery voltage is at 14.4 after the truck has been driven and is still running and you still have a starting problem then you either have a bad battery or a bad starter - assuming the timing isn't too far advanced and the cables are good. So, if you think the battery has to be good because it is new, replace the starter at that point.
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Posting Guru
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I'm not going to get three bad batteries in a row, and I replaced my starter the first time it essentially did this, because that was my first geuss(plus I was stranded and hungry and had a long day) then it was great for a week (barely bump the ignition and she roared to life) but as the engine warmed up, and days went by, it got harder and harder. Then it acted like my icm went out, so I replaced it and carry a spare now. Now it's still doing it but not so sure it's the same thing or the cause
FTE Legend
Joined: Jul 2010
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From: Northeast, OK
Let me know when you cleaned every connection on the battery, starter, and ground cables as well as checked the cables themselves. The latter is because some crimped on connections rot away but look good.
One way to test connections a voltmeter across the connection and set to the lowest voltage scale. Have someone try to start it and watch the voltage. You shouldn't have more than .01V across a good connection.
One way to test connections a voltmeter across the connection and set to the lowest voltage scale. Have someone try to start it and watch the voltage. You shouldn't have more than .01V across a good connection.
Senior User
Joined: Sep 2013
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From: Marlborough, CT
If you are using the bolt-on lead heads at the battery end, don't. Notorious for poor connections. Either buy a premade cable or solder on your own. Or have one the correct length made at an industrial battery supplier.
Bill
Bill
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Joined: Jul 2010
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From: Northeast, OK
Under what conditions is it between 13.85 and 13.99? If you've just started it and it is idling that is probably fine. In fact, those aren't bad #'s since you also don't know how accurate your DVM is. If it is off even .2V you are in the proper range.
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13.99 was at start up (cold engine, went through the high idle to warm then dropped it and played with lights on and radio on )
13.85 was after a twenty minute drive so I figured it was plenty warm
13.85 was after a twenty minute drive so I figured it was plenty warm
FTE Legend
Joined: Jul 2010
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From: Northeast, OK
Grrrr. I had a response typed in and lost it. Anyway, your regulator and alternator may be fine. The optimum set point voltage for a battery varies with temp, and the warmer the lower the voltage. So the 13.85 after driving may be ok if your air temp is very warm - like 100 degrees. Otherwise it is a bit too low.
Try one more test - check the battery voltage first thing in the morning without turning on any electrical load at all. You may have to pop the hood the night before so you don't have to open the door and have the dome light come on. But if the battery voltage is 12.8 at that point then your meter is good and the battery is charged. Replace the starter.
Try one more test - check the battery voltage first thing in the morning without turning on any electrical load at all. You may have to pop the hood the night before so you don't have to open the door and have the dome light come on. But if the battery voltage is 12.8 at that point then your meter is good and the battery is charged. Replace the starter.
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Grrrr. I had a response typed in and lost it. Anyway, your regulator and alternator may be fine. The optimum set point voltage for a battery varies with temp, and the warmer the lower the voltage. So the 13.85 after driving may be ok if your air temp is very warm - like 100 degrees. Otherwise it is a bit too low.
Try one more test - check the battery voltage first thing in the morning without turning on any electrical load at all. You may have to pop the hood the night before so you don't have to open the door and have the dome light come on. But if the battery voltage is 12.8 at that point then your meter is good and the battery is charged. Replace the starter.
Try one more test - check the battery voltage first thing in the morning without turning on any electrical load at all. You may have to pop the hood the night before so you don't have to open the door and have the dome light come on. But if the battery voltage is 12.8 at that point then your meter is good and the battery is charged. Replace the starter.
The underwood area does get fairly warm tho, so I see that as a reasonable excuse.
I'm pulling the starter today to see if it tests good
Another thing, after I drove it last night, I turned it off checked the battery and then went to restart it. It was giving me issues b like dead battery then it would pick up a little then again and again and then she started. Is that my starter?
FTE Legend
Joined: Jul 2010
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From: Northeast, OK
Maybe. Maybe not. What you need to do when that happens is to enlist a friend and do some troubleshooting. Use your volt meter to find the problem. One way would be to put the red lead on the positive battery TERMINAL and the black lead on the positive battery cable. Hit the starter and if you see any appreciable voltage at all you have a bad connection. Do the same on the negative battery terminal/connection. Ditto on the connection to the battery side of the solenoid, and right on down the chain. Same on the ground side. Or, just take it all apart one at a time, clean it spotless with a wire brush and file, and put it back together.
A bad connection can make a good starter into a poor starter. Ditto on a bad battery, but you've replace that so it is elsewhere.
A bad connection can make a good starter into a poor starter. Ditto on a bad battery, but you've replace that so it is elsewhere.