Dodge Cummins Diesel Forum banner
  • Hey everyone! Enter your ride HERE to be a part of October's Cummins of the Month Challenge!
1 - 8 of 8 Posts

·
Registered
Joined
·
442 Posts
Discussion Starter · #1 ·
Now that my daily driver has been downsized significantly to a VW diesel pickup truck that gets 50mpg, the Cummins just sits unless the VW is down or I need a "real truck". I drive the Cummins a handful of times some months, sometimes it doesn't get driven at all. But chances are, if I am driving it there is some heavy weight if not a trailer involved.

Anyhow, I got new Interstate batteries about 2.5 years ago. The truck has always cranked over pretty fast. Even when it does it's "warm and doesn't want to fire off thing" and needs to be cranked several seconds..

In mid December, I drove it, fired off just fine.

In very late december I drove it to haul a car to the tire shop and get it aligned. I borrowed the trailer from a friend of mine so I don't know how good he is with his maintanence. Not sure if any of this is related, but wen I get where I was going, I noticed my brake controller was lit up even when the brakes werent applied. I got out of the truck and noticed my brake lights were on even when I wasnt in the truck. The brake controller was warm. I unplugged the controller and the brake lights stayed on. Said screw it and unplugged the trailer and fiddled with the brake light switch and sooner or later the lights shut off..

When I left the tire place, seemed like the truck cranked a little slower.. But not too bad..

Since then I used the truck a handful of times, or jsut moved it around the property, and it seemed to get slower and slower. I drove it to the Interstate place, and they first checked the batteries. One came out "Good", the other came out "Fair".. Fair is apparantly not bad enough to get a warranty replacement. They checked all the cells with the hygrometer and they came out good too.

Their little magic box also checked the alternator, and somehow the starter, supposedly they are all fine but it is cranking so slow at this point I feel lucky when it fires off. One thing to note is if the truck has to crank for 5-6 seconds it maintains its cranking speed.

I need to get this straightened out because I can't be stuck somewhere with a trailer on the back and a truck that wont crank....

If I was to monitor voltage before cranking and during cranking, would that tell me something?

After i left, I was also reminded of when I had a battery checked out at Walmart.. I was litterally dead at a freinds house and we couldnt get the battery to take a charge. THey said it was fine when checked with a handheld. But since i knew it was the battery I told them to check again with a real load tester and it immediately failed..
 

·
Registered
Joined
·
1,477 Posts
Have you tried jumper cables.
 

·
Premium Member
Joined
·
12,050 Posts
Check the cables for internal resistance. Check ground and heavy circuit connections. While U got er down have alternator tested off vehicle.
You got a dead battery??? Replace both and be done with that guess. Replace contacts in starter. They are most likely cause of a starter issue. don't second guess and procrastinate. Get er done. I know you have the capability.
 

·
Registered
Joined
·
442 Posts
Discussion Starter · #4 ·
According to Interstate I don't have a dead battery..
I have half a mind to go to the interstate store and tell them I will make them a deal.. put a pair of batteries in it and if it starts normal, they warranty them. If not, I will buy them...
the contacts in the solenoid are not that old. Maybe have 15 or 20k miles. I dont think the battery cables would degrade in a week.

Figured there was a voltage check I could do to point me in the direction of starter or battery... not just throw parts at it....
 

·
Premium Member
Joined
·
12,050 Posts
Do a voltage drop between batteries and left battery and starter contact. More than .4 volt drop in power circuit is problem. .2 volt drop on ground circuits. Disconnect pass side battery and crank. do it crank good?
 

·
Registered
Joined
·
92 Posts
check voltage at the starter while cranking and checked voltage at the batteries while cranking, take those 2 numbers (the voltage at the batteries should be higher) and subtract the 2. you should have no more than a 1 volt drop from batteries to starter. another check is to disable the truck from starting (pulling the ecm fuse) and hook up a amp clamp to the starter positive cable, crank engine for about 5 seconds and watch the amperage, should be around 400 amps, any more you have internal engine problems or a junk starter. I think your problem is most likely your batteries, interstates are junk I replace several each week under warranty. hope this helps
 

·
Registered
Joined
·
7,762 Posts
Remove the negative cable from both batteries tonight.
Tomorrow morning check the voltage on both batteries...junk out any less than 12.5 volts dc.
 

·
Registered
Joined
·
1,136 Posts
I suggest strongly that you drink beer tonight. Thank everyone that's trying to help you and do what clunk said
 
1 - 8 of 8 Posts
Top