My N14 Has Gone Through Ten Injectors Within a Year

So the n14 cylinders don't work in pairs?

 

All 6 cyl engines have companion cylinders. 1 - 6, 2 - 5, 3 - 4.

I have trouble following this train of thought because no injector fires at the same time, mechanical or electronic engine.

2 injectors also share 1 head in an n14 or 855, but thats about where it ends.

Each injector is cam actuated, but also has a solenoid for controlling fuel metering. there is a cam lobe for each injector. Each solenoid is controlled by an injector driver in the ecm. This is the only ecm output in a celect plus that generates much of any sort of amperage.

Each injector solenoid has its own dedicated supply and return from the ecm. No where do they, or are they suppose to, share any sort of signal with each other.

I have personally never heard of this. Theres lots of reasons to recommend multiple injectors in a repair, but I've never heard this reasoning. I'd be interested to hear the thought process behind it.

Just a thought.

 

And one other thing I thought of relating to OP:

Wouldn't hurt to pull, inspect, and clean the fuel jumper tubes between cyl head. Make sure they are sealed and not leaking. The ecm check valve loved to collect crap(especially if your n14 had the remote mounted filter option) but these little guys are commonly forgotten about. (Myself inclided! As I forgot to mention in my original post.) Remember the micron rating isn't very low for your fuel filter on these old engines. You can also check fuel return restriction from the engine back to the tank.

I'd love to keep updated on this specific issue you're having. For some reason I always enjoyed the hair pullers.

Thanks and good luck!

Circling back to low psi fuel checks -- though a minimum at the gear pump of 125 psi is good, make sure it's a steady reading. Fluctuation in the gauge can be indicating an air in fuel issue or a dying gear pump. Best to check with a clear line directly on the pump inlet. Also, make sure the gear pump is building 25 psi within the first 6 seconds of cranking. Normally you would have long crank times, cold or hot, associated with this. But if it's very slow to build pressure than you are having pressure regulator issues in the gear pump. This all, or none of it, can be relating to cavitation as you mentioned earlier. I've also attached a diagram of the guts behind the PT switch that should be at very least checked and cleaned, at very most replaced. I'm not usually in the habit oof parts chucking, but pt switch guts were always first to be replaced when I ran into fuel system trouble I couldn't nail down. Cheap insurance amd very often neglected.

There is a check valve on the return of the gear pump as well that should be checked.

 

No they don’t. They have companions. When #1 is tdc on compression stroke #6 is tdc on exhaust stroke. You only have one cylinder firing at a time.

 

Definition for companion-
2. one of a pair of things intended to complement or match each other.

 

Thanks Merriam-Webster. Maybe you can quote Chilton and help get this guy fixed up. It’s the mechanic’s section. You’re supposed to work with tools, not be one.

 

Seems to me the most common denomenator on N14 innector failures is they are all electric fired. The basic injector is still the same as the old mechanical NH injectors. Their failure rate is very low and they seem to last forever as long as fuel is clean. I’d bet that majority of the electronic injectors are not getting the electric part of them properly replaced or repaired. They check out ok on a bench test under room temperature and are considered good. Then when put in hard service thru real world heat cycles they fail.

 

As they age, it seems the rate of good recon injectors are becoming abysmal. The reasons why are easily debates if you've been around Cummins Inc in the last few years, but thats not applicable here and is a different conversation for a different time.

The celect plus fuel system is kind of known for eating injectors (especially compared to fuel systems like HPI or Quantum for cummins engines), but the rate of the failures seem to be accelerating now. I don't think you're wrong, but harnesses with stray voltage and computing technology from 1996 that has hundreds of millions of cycles(relatively speaking) of output amperage, in my personal opinion, aren't helping either.

To demonstrate the age of the celect plus ecm, if you have an n14 with a celect or celect plus failure from the dealer, they are no longer available and are instead pushing a TSB to change the ecm over to a CM570 with an adapted engine harness for the celect plus sensors.

I think the injectors, harnesses, ecms, and trucks are just getting old, and the new and recon parts thrown in the mix are just not up to snuff anymore. They're not rebuilt the same like they were in the 90s. That's just my humble opinion as a dumb ditch digging tech though.

Just a thought.