Hi all I wanted to get some opinions on a charging issue with my 99 24valve. I went elk hunting two weeks ago and it got down to 15 degrees the old girl didnt want to start right off the bat so I cycled the key on and off till the wait to start light went off and had to crank the heck out of it but it started I didnt have a place to plug it in at our camp. Two weeks later the volts go up and down which they did before with the grid heaters, I only hunted 10 miles from my house and I only drive about 5 miles to work, I dont drive my truck alot, well this morning I start it and it cranks slower than normal I let it warm up for about 15-30 min every morning and I plug it in every night, I go out at lunch and the volts were at 8 and it wouldn't start. My question is if I got the batteries voltatge down pretty low would it have had time to recharge itself with the alternator? I jumped it and let it run for 1/2hr and drove home it was warmed up. I checked the voltage with a volt meter and it was at 14.2 I turned the truck off batteries were at 12.6 I had my wife crank it over it went down to 11volts fired right up. The volt meter was low agin and started the up and down like the grid heaters were on, I had my wife bring up the idle and it stayed the same the Voltage at the batteries was 12.5 at this time after about 2-3 mins the volt gauge went up to 14 on the dash and my volt meter showed 14.1 at the batteries. I disconected the batteries and I am going to trikle charge them seperatly over the next two days. I know this is a long post but I wanted a little feed back before I buy new batteries. They are about 4 years old. I have never had a problem before the week. Thanks

 

You should have them load tested. If one is bad (dead cell) then it will drag the other one down. You should check the voltage after 24 hours of the battery's sitting then load test and check again.

 

I agree load test but first give them a good charge for a long time then let set for an hour and load test. I had a problem like yours with my toy truck and finally put on a charger for a good long charge and has been working fine since. It does not get driven much or regularly. Can also check to see if there is some draw on the batteries when truck is off.

 

Ok I charged both the batteries seperate and they checked out good on a load tester. I hooked everything back up started great, with the load tester it has a gauge to tell you how your charging system is working, on start up the alternator was not putting out voltage but after a short time it got up to almost 14 volts I let it run for about 45mins or so and checked it again was charging at 14.2volt as soon as I turn on the head lights and put my heater on full it dove down to 12 volts. I am taking my alt to get tested at orileys and it is a 3 year old rebuilt one from them. Does this sound like the Alternator to you guys or are my batteries tricking me? I have to drive 30 mile to my closest Orileys to get it tested hope this is the problem.

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Also I didnt put it in my first post but when I was hunting I had to jump my buddys 2010 cummins and that is the only thing that I did out of the norm. Aslo I noticed when I put my cables on the arched a little is this normal with the newr computer controlled trucks because with the older ones that meant you had a draw. Thanks

 

You may have damaged your alternator while boosting your buddies. As long as you keep the load down on the system, lights off heater only if necessary, you should be able to make it 30 miles easily. Even with no alternator you should be able to make it that far on 2 batteries.

 

if you are getting 14 v after a couple of minutes, but not right away, then it could be in the regulator circuitry, but lets hope thats not really the case, and you just have a dead cell somewhere.

 

I'm having a similar problem with my truck. Slow starts acting like the batteries are drained. I had one battery where the posts were loose so I replaced both batteries and positive terminals and cables. Still slow starts... I think it could be the starter is on it's way out. I sure hope it's not the alternator regulator system...aren't these Alts regulated through the PCM? My voltage gauge takes a bit to climb while the grid heaters are doing their thing but it does climb up to 14.4 after probably 20 seconds.
Anyway sorry to hijack
For my problem I'm gonna try rebuilding the starter and see what happens

 

Well took the alternator to be checked and sure enough it was only putting out 8 volts on their tester with a load. Put the new one on today and started it in 40 degree weather not plugged in and she jumped right up to 14.4 volts and would dip less than ever before when the grid heaters kicked in. Turn on all my acessories and the gauge didnt even move. The head lights had never been this bright before, so I think my old alternator was going out when I bought the truck. Also when I took it off when I would spend it you could hear a squeeking noise in it. So thank goodness it was just that and not the PCM. Thanks to all your guys help.

 

Glad its all fixed up!