i work at the top of the world. the arctic. Baffin Island eastern canada. this is an iron mine exploration camp, we have lots of cat equipment and we take daily care of them with a 2002 Dodge cummins service truck

lately the truck has been cuttin out 3 cylinders very randomly and its been gettin worse and worse. usually drive in 3rd gear but it happens in any gear, and at any rpm,randomly. theengine runs perfect when its on 6, and randomly it will kickout 3 cylinders. To bring it back to 6 cylinders, i press in the cluth and let it come down to an idle, and it seems that as soon as it comes down under a 1000 rpms it will run perfect on 6 again.
could it be a bad connection somewhere??? i know these trucks are capable of droppin 3 cylinders, but this is just a random cutout and unable to control.....

any ideas????

 

How are coolant temps when this occurs?

 

everything is fine.....coolant is SOMETIMES a lil tiny bit over...but not much at all...the truck weights 12000 pounds and on the mountains it comes a bit over but regardless of that it still does it. oil pressure is also normal

 

I am only guessing here but have the lift and injection pumps been checked out? The second gen trucks are known to have issues with these items. Also if the truck sees a lot of idle time it may be possible that you have some carboned up injectors.

 

yea it does see a lot of idle time, my rotation is 4 weeks on and 2 off and it runs for that month straight but only works durin day shift, so idles all night, cant shut it off cuz it freezes rite fast up here....

 

try reseating your injector connectors, crank, cam, MAP, and IAT as well. . .just unplug them, blow them out, and plug them back in.


I know these trucks will do a 3cyl shutdown on startup when it is very cold. it does this to help warm the cylinders up so you dont get a washdown of the cylinders. However this only happens when the vehicle is not moving.

 

Dang, you leave it idle all night long? Don't you have a block heater? Or is it not good enough for the temp?

 

I would say mostly for the fuel in that it would gell at those temps. the CP3 produces a good bit of heat and that is pushed back to the tank.

another thing is steel becomes VERY brittle at those -40F and lower temps. keeping the engine running will keep the metal warm.

 

Here is the information I've got on it...
http://mopar.mopar1973man.com/2002%2.../high-idle.htm

And here is a thread I just posted about 3 cylinder highidle...
https://dodgeforum.com/m_1242189/mpa...tm.htm#1243156

Things that will cancel 3 cylinder high idleit...
1. The Automatic Transmission is placed in gear (forward or reverse) or,
2. The Service Brake pedal is depressed or,
3. Throttle position is greater than 0% or,
4. Vehicle Speed is greater than 0 mph or,
5. Coolant Temperature is greater than 79°C (175°F).

All these thing must be true to enable high idle or 3 cylinder high idle
1. Intake Manifold Temperature less than 0°C (32°F) and,
2. Coolant Temp is less than 60°C (140°F) and,
3. The Transmission is in Neutral or Park and,
4. The Service Brake pedal is not depressed and,
5. Throttle = 0% and,
6. Vehicle Speed = 0 mph

 

yea its been mild lately, but hard winters here, we have herman nelson (oil burner heaters) and when trucks have problems we need a heater in the back of service trucks to warm them up incase they have been shut off cuz they'll never turn over. 0 40 oil thick as grease.
the thing is that they 3 cylinder cutout will happen a high speeds. high engine speeds. lots of throttle.
maybe derate temp? but why would it come back on after pressin the cluth and lettin it idle down below a 1000...??? im confused....its not a constant problem so its difficult to find.