91 N14 Cummins intermittent miss

If when you unplug a cylinder and it stalls you have a bigger problem.
it is an electronic engine and should just keep adding fuel to the ones connected. The Pass thrus fail quite often usually at a certain heat range.
What I do is when I change an injector, I keep the wire harness off the injector, it does not change the core value. It will plug into the pass threw, when it has a Miss and you test the resistance .5 to 1.5 If it is open then unbolt the pass threw and pull it out put a pick between the wires of the connector, unplug the injector, and test the resistance again if it is .5 to 1.5 then the pass threw is the fault. Buy it with the "O" ring.

 

Looks like you might be on to something..

We've had a few with intermittent N14 issues,
1. Loose ECM cable at the batteries. I found out by wiggling the cable and it started missing. Tightened it and voila. Fixed

2. Corrosion at ECM fuse at the batteries. Found out by removing and replacing fuse and would not start. found fuse holder corroded, but could not be seen with fuse in it. Replaced fuse and holder - trouble fixed.

3. Very int miss all of a sudden. Driver said he had fuel filter changed at a "major" chain. Did battery of test and saw bubbles in Davco see thru fuel bowl. Pulled the see thru cover off and found 0-ring installed incorrectly. Replaced correctly and fixed.

4. Majority of the time an injector cut off test will catch a faulty injector. If not, we run a pass thru with a switch to the cab and take for spin. Kinda like you did. If it does not change on the injector it is on, then more than likely there is your culprit.

While you are at it, please change your piston cooler nozzles, we had one break and good thing driver caught it in time and didn't fry a piston. see my thread here http://www.thetruckersreport.com/tr...s/210866-n14-cummins-low-pressure-solved.html

$8 bucks a piece for a peace of mind.

 

i had this problem also, not injectors... first clean your check valve at the outlet of your ecm cooling plate,check fuel lines for flow. If no change,
replace engine position sensor about 40 dollars, that sensor is bad about not throwing a code. and replacing the fuel soleniod wouldn't hurt (around $95). Also make sure the ECM cooling plate is flowing fuel, they are bad about clogging up on trucks that run off road( dirt in fuel from opening dirty fuel caps). of course a clean fuel filter is first but i would do this first before changing injectors(they usually throw codes when bad). hope this helps.

 

If your cpl is 1580 I can give you a great deal on a set of injectors that were used for only 6 months.

 

I have a n 14 1999 model had same trouble one of the first things to do is be sure all your ground cables are clean the ground thats comes from the starter to frame can be trouble be sure it is clean and tight . also on my freightliner it has a ground from batteries to the frame i had trouble there. when i gave in took it to cummins the real trouble was the plug on the came sensor . was bad it wasn't the plug on the sensor but the lead that it plugs into.

 

I have a n 14 cummins i rebuild the motor last June 2013 all new pistons bearings rods rebuilt 6 new injectors . last week i was coming through Louisville Ky headed to the house . motor started knocking . come home on the hook. about 180 miles $1150. started trouble shooting . i gould tell it was in the top of the motor . i pulled off the center head an turned the motor by hand # 3 and 4 piston comes up at the sane time . when i got it to the top and they started back down #3 moved down about a fourth of a inch be for # 4 moved when i looked at it the # 4 piston was at the top of the liner in front and in the back was down about a Fourth of a inch. pulled off the oil pan and # 4 piston and rod . and the piston broke off where the pin goes through. has anyone ever seen this . i been at this a long time never seen one do this. i have a pic of it o face book .