Originally Posted By: dnewton3
The HEUI system is often misunderstood, and susceptible to many malodies. When properly maintained, it's a very good system. Unfortunatly, because people don't understand it's full operational parameters, things are often misdiagnosed, and therefore blamed.
I'm sure that truly neglected OCIs have resulted in poor performance and injector issues; the system of course does run on oil-over-fuel. However, the is only part of the systems. Hydraulic Electric Unit Injection; the name says it all. The hydraulic is only part of the system, and yet people ignore the other very important part.
Many times the poor injector performance (slow to start, sluggish acceleration, poor fuel econony) is a result of the FCIM going bad. And many times the root cause of that is the battery voltage. This is information that has been around for many years now, but it's easier for some "shade tree" guys to blame the easy stuff; blame the oil. I'm not calling anyone out here, but I'm pointing this out because some would easily rush to judgement without being able to articulate the full circumstances around HEUI. When battery voltage is weak and/or charging system amperage cannot keep up with demand, the voltage to the FCIM drops and that in turn causes the injector voltage to drop, resulting in sluggish response and/or outright injector failures. Or, quite often, the FCIM itself will eventually fail. Most often, we think of electronic failures as "all or nothing" when it just "dies" a sudden death. But the FCIM more often degrades slowly, sometime so slowly that it's not noticible to the driver over many, many months.
There is a reasonably articulate article in the new Diesel Power magazine; it's a decent read about this very topic. It rightly points out that weak batteries are the root cause of the FCIM degredation, and even after you replace the batteries, the problem lingers because the FCIM is compromised. People will replace the batteries, and then blame the only thing that pops into their head; blame the oil.
I'm not saying that is the case in all PSDs. I'm just pointing out that "extended OCIs" (lube related issues) are not the only cause of injection issues with HEUI. In fact, if the oil change extension is well controlled (solid UOA parameters, bypass filtration, etc) it's more likely an issue with the FCIM.
I agree with your entire post, but would also like to add what I was attempting to explain in my above post is that there seems to be some brands of oil that seem to be much more trouble-free than others.
There are several different oil additives available to address "injector stiction", and from what I have read they seem to be somewhat successful in acomplishing what they are advertised to do. The unknown is are they actually masking a low voltage FICM issue?
There are many who have had to have injector replacement, how many are oil related are unknown, but as we know here there are many different avenues one can travel to reach the CJ-4 spec. More of one additive and less of another "could" be causing injector issues.
There are many 6.0 guys swearing by switching to synthetic lube is the cure-all to injector issues, and I for one have never experienced an injector issue in nearly nine years over two trucks using 15w-40/10w-30 Plus 50.
After reading much about this issue several years ago I made the switch to a 5w-40 syn, after three consectitive runs with successive UOA's I came to the conclusion that my engine actually had higher wear numbers with syn.
Thats when I made the switch to 10w-30, and quite honestly I have no reason to look anywhere else for a lube choice, excellent UOA's, reasonabely priced, and good year around performance.
My current 6.0 ('07) as my previous one are my work vehichle, towing occasionally, but loading the bed up to 4,000 lbs. and running 150 miles down the highway in 90`f summer heat. The combination of my usage with lube choice is working in my application.