06 MXS Cat C-15 Injector / electrical issues have us stumped

Are all your battery connections clean and tight? Make sure the battery cables are not rubbed through anywhere from where they exit the battery box and run along the chassis, especially the one that runs to the ecm. Good luck.

 

I am stumped too, I'll tag another member here and see if he has come across this problem before.

@GrapeApe

 

Is it possible this is a mechanical fault, not an electrical one? I'm not super savvy with Cat's on road engines but I have seen engines from other brands throw all sorts of injector faults and codes due to something as simple as a plugged fuel line.

 

I have seen the injector nut plate slightly bent and the two metal plates slightly touching and shorting out throwing random injector codes.
Going for the crazy/ uncommon you could have electrial noise in the system being a faulty alternator or poor/ missing ground.
You said you replaced the outer harness multiple times, what about the inner harnesses? The inners usually fail more often then the outer harness. Corrosion in the ecm plug?

 

I need a better explanation of what you've done. Code 74 could be 5 or 6. Did you use Cat ET to find the correct one? What was the exact fault code (SPN and FMI). Did you run a cut-out test and injector solenoid test. When you say swapped injectors, does that mean replace with remans or just swap around cylinders.

It seems that everything you've done so far is EVERYTHING that would normally cause that issue. So the only logical conclusion is that you missed the issue and need to start over.

An intermittent issue is usually wiring. With all new harnesses from the ECM to the injectors, I'd be looking at power from the battery to the ECM. Actually load test each power and ground to check for voltage drops. High resistance will show battery voltage in an open circuit, it needs to be checked with a load on it. A headlight bulb works if you don't have test leads that can load it.

If that checks out OK, the next thing I'd verify is that you have 60 ohms on the J1939 data link. Data links can cause very strange things to happen.

 

Did you ever find this problem cause I am having the exact same problems and am at a loss

 

Did you ever get this resolved?? I am having the same issues on the same motor!?

 

Had this same issue, ended up being injector nut & sleeve on #5 cylinder