The most common issue of fuel in oil I read about here is trouble with return line fittings and that would obviously not
throw the P1093 since those lines are just low pressure plumbing, directing unused fuel back to the tank. On the other hand, high return rates, due to failure of the return ball/seat inside
one or more injectors might disrupt rail pressure, but would not fill your crankcase with diesel.
Early in the production run, LB7 injectors had metallurgical problems that resulted in cracked and leaking bodies, but I believe all of those injectors are long gone from the gene pool.
Regarding your thoughts about replacing HP lines, if you look closely at your engine you will see those lines from the common rail to each injector are external
to the valve covers and any fuel leak there would result in diesel escaping the system (and a P1093) and soaking the top of the engine, but not getting under the upper valve cover and into the crankcase.
Something else I should mention in regard to replacing those lines. If you look at the HP connection atop each injector you will notice there is a small gap around the nut and the line. That gap accumulates water and then rust and when the line is removed, all that debris inevitably falls into the top of the injector, where there is a screen (for all the good it does) and is impossible to remove without injector tear-down. Since most folks who have dived that far into their engine are there to R&R injectors, the junk doesnít matter, since the old injectors become cores.
In your case, that rust is going to be there (unless someone sealed around the aforementioned gap) and you know where itís going to end up.
Back to bad HP lines, there should be external diesel somewhere if one failed, but again I havenít read of that often, although the connection to the injector has been known to leak. But again, where are signs of external diesel and how is it getting past the seal around the injector and upper valve cover?
Any failure of HP lines should be identifiable by using tissue or somesuch to absorb any leaking fluid.
I donít need to remind you, but I will, high pressure diesel is DANGEROUS so check with utmost caution.
Well, Iím afraid Iím not being much help here and sure wish someone else would join the conversation.
Only thing that comes to mind is maybe you do have a cracked body (as unlikely as that would seem) but you said the engine is running fine. (???)
There are inexpensive apps for iOS and Android that can be loaded to a smart smart phone and, with a comm device in your OBD2 port, read balance rates (plus lots of other useful 411) and would tell you if a cracked injector is bleeding off rail pressure. TECH2 is what the big kids use in shops, but very $$$.
Finally, you mentioned that ď...since March...Ē towing performance is degraded. Other symptoms?
Címon gang, help this guy out!