Hi all, 1996 dodge ram diesel 2500.. When I start the truck after sitting 24 hours or maybe even after only 12 hours, It starts like batteries are low. Like a hard turn over and then about 2 or 3 second slow grind and it will run fine at idle and at speed. I put only two of those square battery cable clamps that have those 4 holes one for the large wire and smaller for the other wires. I will buy two more because I used the two fore each plus posts on the two batteries. When Truck is not running, Batteries both show a little over 12 volts. As soon as the truck starts,, The voltage gos up to over 14 volts. Even when I have Lights everthing on while running. Now what I tryed is,, When the truck is sitting for a day or so,, I wait for the start lite to go out, I allways do. Then turn the key and immediately press on the fuel pedal just a little and it will start right up instantly. The batteries are about 3 to 4 years old. If batteries are showing a little over 12 volts when truck is not running and then over 14 volts while running what is going on?? Could the little wires or any of the wires in those new square clamps not be touching right?? Is one of the wires for the fuel pump??

 

There is no electric fuel pump on these trucks - unless you or a previous owner added a FASS/Airdog/other system. All fuel transfer is done by mechanical pumps - the lift/transfer pump on the block and the P7100 injection pump (fed by the lift pump). Your sig line indicates no modifications, so we'll assume no electric lift/transfer pump has been added. Your terminals sound like something sold for automotive audio use. Can you post a pic or a link to those terminals? How long have they been on the truck?

Those terminals sound like something that will allow corrosion to start and spread under the insulation of your battery cables (and all the other wires attached to those terminals) - that will increase resistance and cause "voltage drop" (google it) which can lead to slow cranking and is hard on the batteries and starter. That's the first thing I'd look at - to test that, you'll need a digital multimeter so you can do voltage-drop tests on the positive and ground cables.

 

High Quality Positive or Negative 1/0 4 8 Gauge Input Battery Terminal

Notice large hole. I put the larger plus wire from both batteries to that large hole.It fit perfectly.I only bought two clamps so one marked negative is on the other pluss side battery there both the same except the negative one where it gos over the post,the squeeze clamp is a touch smaller to put on the + terminal. I felt they must be for trucks. No corrosion on top or inside them. Only on for week and a half. The smaller holes is what im woundering. I may re do those.

 

 

That set screw that tightens down on the cable is not going to give you very good contact between the terminal body and cable. That's one place you are probably having issues. Crimped-on terminals, if done properly and from what I read, essentially cold-fuse the terminal body and wire into one where they are crimped - or there are solder-terminals. In either case, there is full contact between wire and terminal with those - and you don't have it with that lash-up. Putting the heavy draw of the diesel starter on cables that don't have adequate contact is a recipe for problems.

"No corrosion on top or inside them" - I assume you are saying there is no corrosion in the terminals themselves. What about on the cable strands, both in the visible areas and under the insulation? If you look at the cable that's been added on the side using the terminal pinch bolt - notice the gap between the insulation and the terminal barrel. I would bet there is corrosion up under the insulation - and you may have it (out of sight under insulation) on the positive/negative cables What gauge are the cables from battery to starter, battery to block, and plus/plus between batteries? You need to do voltage-drop testing on those and see how much you are losing under electrical load. Are those the original cables? Why are the "normal" terminals missing, and how long have the cables been like that? Lots of possible issues here...

 

I would let it sit, disconnect both grounds, and test each battery separately if you haven't already. A 'good' battery will have 12.4 -12.6V or about 2.1V per cell (6 cells). . "Batteries both show a little over 12 volts". What's a little? 12.1? My guess is one or both of the batteries is going down. 3-4 years is not new.

Idk what the push the throttle pedal has to do with anything. Coincidence? 14V at idle/running is good. Also, check your Engine OFF current drain. You should be able to measure some 10s of mA, but 100-200+mA means some accessory is going bad (stereo amp is the usual culprit). By process of elimination, the battery cables were corroded/bad and you replaced them. Seems like a good part you used to repair them. I would also check the battery cable at the starter just in case. Good luck.

 

If the idle is adjusted on the low side of the tolerance the "little bit of pedal" for starting is in the Cummins manual for those engines.

After standing for a day or two you have an internally cold engine and batteries that have lost their surface charge- so cranking speed is a little lower than on a warm engine with batteries charged to the gills.

 

Good call on the age of the batteries, Dean. Nowhere does the OP say that he replaced the battery cables, though - so cable corrosion and voltage-drop should still be a suspect. OP - in addition to the parasitic draw that Dean mentioned, it would also be a good idea to test the starter current draw. You'll need a digital multimeter and a high-amp current probe (good for at least 600 amps, preferably more - example) or a clamp-meter (example) that has the probe and meter integrated. If you don't have those, or can't find/don't want to buy - an auto parts store may have a handheld battery/starter tester that will handle that. There are internal starter issues that can cause slow cranking, and the current-draw test will help reveal them.

 

I had a starting issue with my truck where I rebuilt the starter and replaced the batteries it still did that. Turns out I tried to save $$ by not replacing the clutch thingy inside. its the heavy 75$ or so part that the output gear is on. Once I did that I have had zero starting problems.