I have a 94 dodge 2500 with cummins. Today it would not shut down when the ignition key was turned to the off position. It finally stopped running about 20 minutes later. It now will not turn over,batterys are good.

I noticed a lower rpm like it was running in a limp mode after I tried to shut it off. Rpm went from about 800 on the rpm gage to 400 before it shut down.

Dave

 

https://www.dieseltruckresource.com/...s-t228905.html

 

If the stater contact stuck and allowed the engine to run on for 20 minutes you more than likely also fried the shutdown solenoid.
Check it for blistered paint.
More reading> http://www.fostertruck.com/dodge/default.htm

 

Tell me if I'm following along :
The engine was running
You turned the key off
It didn't shut down

Sounds like the shutdown solenoid got hung up somehow.

Those two ^^^^ know their stuff and point to stuck starter contacts though. Bill, are you saying the starter was running the WHOLE time he was driving and then didn't quit till the battery died when the key gets turned off?

Thanks in advance for the education.

 

That could very well be dads old 95 the starter contacts stuck on his we realized it right away when he tried turning off the key it still ran so we ended up pulling the grounds off the batteries.

 

Yep, the starter was most likely running the whole time the contacts were stuck.

 

When my contacts stuck, I could hear the starter still spinning while the engine was running. It shut down and let go, but I quickly ordered the parts to get it fixed right away.

 

Might be to late for that starter.

 

Agreed. IF the starter ran that long and hasn't failed, it will VERY soon. Save yourself the trouble, and put a new starter in it. However, check/replace your fuel solenoid first, then check the starter, solenoid, and wiring for discoloration and /or burns.

 

You would think a starter would burn out after running an extended time but I've owned a 12 volt fertilizer/seed spreader that mounts to a tractor that runs off a starter motor.
There have been many times when it's ran all day.
Same starter motor for many years.
Many of the salt/ice melter spreaders you see mounted on the rear of pickups are powered by a starter motor.

Recently a fellow I know who repairs aluminum irrigation pipe showed me the machine he use to hydraulically press pipe together in the field.
The hydralic pump was powered by a starter motor.
It didn't run all day though, it only took three hours to run down the bank of four batteries that powered it even if he kept his truck idling to charge the batteries.

Note the starter motor at the bottom

 

If the starter runs with no load, its just an electric motor and is not harmful. Its when the starter is at full load, like turning over a dead engine, that they get hot and damage the windings. A running cool motor is not an issue.