Startup problem with my 2006 Ram cummins manual trans.

At times my starter motor cuts out. Cranks at full power for 1 to 3 seconds then it just shuts off. Not slows down, just cuts off. Release the key try again, same thing. After a few tries it will finally fire up.

Anyone ever seen this. Ignition switch? Clutch peddle cut out switch? Some starter motor relay?

 

Think I would start with the relay.... Just swap it with another one.

 

The last 3 days it has dropped below zero by morning. I have started the truck when the temps have moved up to about +5F. Starter keeps cutting out. Drive to lower elevations where afternoon tmps are +20F and it starts okay. Today it was 0. Same problem, took many tries. before it would fire.

I checked my records and both batteries are over 5 years old. I guess that's the problem. I only drive the truck 5000 miles a year but I guess a 60 month battery only lasts 60 months no matter how much you use it. With the grid heater and 0F tmps, they just can deliver the amps needed. Got 2 new batteries and will give it a go. I'm sure that is the problem. I just didn't realize 5 years had gone by.

 

Does the solenoid kick out, but the starter continues to run? Or does it stop cranking altogether, and silence.....

 

Also check to see if you can hear the fuel pump engage. I just replaced my fuel pump for the same thing.

 

It will start after a few tries and run so I doubt it's a full pump issue. I'm sure its just 5 year old batteries. In the middle of some big snow storms so if I'm lucky, I will get the batteries installed tomorrow.

 

Had a break in snow storms and things warmed up. I removed the 5 year old batteries, cleaned everything up with a a bucket of water and baking soda. Installed the batteries. Forward 2 days and the tmps are back down to 3F. Turn on the key, wait for the grid heater to come up and the truck now starts fine.

So it looks like it was just old weak batteries which could not supply enough amps at zero temps to start a 20 to 1 compression motor.

 

At least it was an easy fix, and the weather kinda cooperated.