My 1996 12 valve starts up fine cold, then if I run it to operating temps for awhile and drive it around doing my thing eventually shutting it down for a quick minute or two, when I go to start it back up it will fire and die instantly sometimes only doing it once and sometimes doing it a few times. It usually takes me giving it a little throttle when it fires to get it to keep running. Sometimes that doesn't work and it will still die on me. I changed the fuel filter and nothing changed. When truck is up and running it idles and runs perfectly fine.Any ideas what would be happening?

 

sounds like you need to up the idle a little should be around 800 +-

 

I usually always let the truck idle normal for a few minutes then stick my cut off hockey stick between the seat and pedal for idle up to 1100rpms, still smokes blue. I was told of some overflow valve of some kind that needs replacing almost every 60-80 thousand kms. Would that be a KSB?

 

Sorry I misread your post, I'm not sure what its idling at right now. I'll check that but like I said when I put the truck on high idle it will still smoke a blue haze until I actually drive it.

 

bump anyone? KSB or what?

 

mine had an issue with the return fuel line it chafed thru on the transmission and had a pin hole in it,,,but it was weird to start while warm.check your shut down solonioid it may be giving grief!my 96 has an idle issue now and then but its the paint chipping off the idle screw(a paint chip is about 200 rpm thick...i know sounds weird but the tech at cummins said it was common)) and it idles too low when you turn on the defrost (the a/c works with the defrost) it will stall the engine in traffic resulting in a large cloud of black smoke usually in the drivers window of a smart car(honest i don't mean to!...lol)the idle must be around the 800rpm,there is a line on the tach the one below the 1000rpm mark, where it should idle.good luck keep us posted.cheers

 

My truck is idling fine, its only when the truck is warm when I shut it off that it will do the start up for 1 second then stop, it takes pumping the throttle at startup to get it going again, even then it takes a few starts to fire and stay running. Its odd. Its getting worse, im worried I may shut it off and it may not start again at all eventually....

 

After you crank it and it doesn't start leave the key in the run position, pop the hood and check if the shutdown solenoid is pulled up.
Round object is solenoid

 

If the shutdown solenoid was acting up, do you think the truck would fire up for a second then shutdown, or would it just not allow the truck to fire at all?

 

Yes - that can happen if the "hold" side of the solenoid is failing or has failed. The pull side works during starting, which is enough for the engine to fire, then when you release the key to "run" mode and the "hold" coil in the solenoid is energised, it can't hold and the engine shuts off again. That's exactly what happened to me a few years ago. You should also check the electrical feed to the "hold" side to make sure current is present when in "hold"/"run" mode.

 

x2 on the solenoid, my truck has a 400rpm idle and fires up perfectly on a restart anytime after its been run. it has less crank time than alot of my modern gassers do

 

What I would do is remove the solenoid, clean it's innards and replace the boot if it's falling apart.
Boots here> http://www.fostertruck.com/dodge/default.htm

If that doesn't get it you most likely have an electrical problem, but not the solenoid itself.
Could be a loose connection or bad key switch.

 

Thanks everyone, I'll check this stuff out and report back. I haven't had a whole bunch of time in the truck lately to check anything out

 

So I finally checked the solenoid today. When the truck wouldn't fire, i left the key on, popped the hood and the plunger on the solenoid was still down all the way. I forced it up by hand until it clicked and it would stay up and the truck would fire right up. So I think either I need to clean the solenoid up or I have some electrical current problems. Maybe I just need a new solenoid altogether.

 

thats what mine was doing also,i changed the solonoid with one from a small kubota generator,and still the same it ended up being the relay.make sure the connectors are contacting i bent the blades on mine a wee bit to make sure it contacted.