For work I run a 2000 Western Star, with a N-14 Cummins (525/1850). Recently It has started Sputtering, Smoking (white/grey/black) and missing horribly, then heres the weird part...You shut it down for a lil while, and it will go away. Yesterday It did it again, we hooked a code reader up and it told us that the Crank Positioning sensor was bad, so it was replaced. There was also a code for # 3 Injector as well. After replacing the crank sensor it ran fine. (still started hard though which i'm thinking is the injector.) But still when your starting to put the power to it it cuts off the fuel and brings it right back rfesulting in a huge bounce, which I'm scared because I figure it'll take out a drive shaft or rear end.

Any suggestions on what to check?

Here's Some pics of what I haul:

 

Dont blow the #3 injector code off. Get a cutout test run. More than likely you have #3 failing or a wiring problem to the injector itself.

 

I had a problem sort of the same I guess, I have a N-14 that when you would shift up to the next gear would sputter and buck, I had a friend of mine at cummins run a diagnostic check which came up with the program showing nothing wrong!! I ran for a few weeks, then one day when I finished my run, the truck was missing at idle, so I flipped the hood and started unplugging injector wires till I unplugged #3 inj. and the idle stayed the same. (when the other inj.'s where unplugged you could hear the change in rough idle) when I pulled the inj. the bottom O-ring was all chewed up which I found out puts air in the fuel delivery (according to cummins) well I replaced with a new inj. anyway and all is well for now. If your truck has a rough idle unplug the wire harness at each inj. till you find one that doesn't change the idle. you said that #3 was bad, my guess would be thats the problem. but like I said, I would pull others to see, if another one might be bad. Mine never threw a code when the o-ring was bad. the N-14 inj.'s are known for having the wires brake inside head. they will throw a code when that happens and ecm will cut power with check engine light on.

 

That's the weird thing though, It doesn't do it all the time, if it was an injector wouldn't it do it all the time?

 

N14s are notorious for this, replace the injector.

 

Yeah, mine didn't do it all the time either. thats why when I got in and it was missing at idle I pulled the inj's. wires 1 at a time to issolate which 1 was bad. like I said earlier, it never thru a code. did you try to disconnect #3 and see it changes idle? when the o-ring was bad the cut-out test showed everything ok, when my inj wire broke the test showed which one was bad. my opinion is that if only does it occasionally, I would bet it's an inj. going south!

 

As stated, it could be an injector issue, I have had the same symptoms on several of our N-14s, no codes, random misses, and high load misses. A commonly overlooked problem is the ECM cooler, it is cooled by fuel and is in the fuel circuit before any filtration. The discharge port gets clogged up with foil or plastic from fuel additive bottles and causes a host of intermittent drivability concerns, (like a missing injector that clears up after it sits a while). Looking at the ECM the input line is on the lower right and the discharge line is on the top left of the ECM, the discharge line is usually the culprit, pull the line off the heat sink then pull the brass fitting out of the heat sink, any debris usually gets caught up in the brass fitting. This is the first thing I check if there are no codes or the problem is intermitent.

Good luck, Tim

 

fixed it, it was the ECM connection... but i broke the **** thing tonight...snapped an axle....oh the joys..

 

How ironic you break a driveline part after you fix the surging problem. That's kinda funny in a not so funny way.

 

**** it driver!! forgot how much power the lil cummalong had!

 

I had a 37 Ton Buncher on, they took be down the wrong road back in the woods, no place to turn no place to unload it. Backed about a mile until I just about came to a place where we could unload it, and then she gave a little spuin (had the 4 ways on) and just before i could reach the clutch SNAP!