4 injectors failed cut out test. cummins n14

If it misfires after tempature is up then I would be looking at a pass thru connector. I worked on Many N14's and never not once change 4 at one time and when they first came out they had many injector problems. I have the wiring off a defective injector, I plug it into the injector wiring outlet and measure the resistance 0.5 to 1.5 is good if it is above that, then you remove the bolt give it a little twist and pull it out, take a pick and put it in between the wires and disconnect the clip then measure the resistance, if it is high it is the injector if it is within specs it is the pass thru conector.
I do not remember where the injector wire harness disconects, never had one fail. You can measure the resistance of the wiring it all goes thru the "C" conector.
Dignostics by the ripping and tearing method is expensive and cures very little except emptying your wallet.
Just a thought!

 

If you plan to keep the truck for the foreseeable future, replacing the entire harness is an excellent idea. Heat, vibration, oil and time wreak havoc on the engine harness. The insulation starts to dry rot and the copper conductor wiring starts to get brittle and connector terminals get weak and spread. This just leads to one intermittent problem after the other. Prices vary, but you'll be looking at about a grand, (don't replace old with junk from a salvage yard, please!). They aren't that bad to replace, few hours or so.

 

I was thinking about this earlier, and got ahead of myself. the first thing you want to do is clean all the battery connections, wash the batteries, clean all the grounds, then with a headlight test the power and grounds to the ECM the three wire coupling is beside the starter. Check the ground fuse on the ECM. You have to start with the basics, it is so easy to get ahead of yourself. I should know better.
Also check the ground voltage drop from the right front of the engine to the right frame rail Stray voltage can cause all kind of gremlins to pop up. I use to add a #4 ground cable to most units I worked on from the alternator mount area to the right frame rail.
Just a thought!

 

What year is the truck?

 

I doubt you have 4 bad injectors but you never know. That age they may be getting weak. I replaced 3 bad ones on a cat this week. I didn't think it would have three go out at once but it did. If I were you Before I replaced injectors I would test harness. Like the others said the harness is old. Do not use a used one if it is bad. Get new.

95 should have the cheaper harness on it. 500 vs 725 dollars. Should is the key word. You can test your harness for shorts if you know which pins to hit. Most of the time a short in the harness will also burn out the ECM. I always test the harness first then if I find if it is bad tell the customer we can replace the harness but get ready for a ECM if you still have issues with new harness install. If you put an ECM on a bad harness it might work for a while but it will fry something before to long. I had a guy that was putting on ECM after ECM and would not change the harness.

 

Not just cummins but cat acerts injector wiring harness goes bad and cuts out when hot, you can actually hear it tick on your cb when it misses connection as a ticking sound.