Oil intrusion to high psi rail system

[funwithfuel]

Hey guys. This one has me stumped. A bud of mine called. Says he's out looking at a cat dozer with high psi rail system. I do not have model and serial. He says when he uses electric pump for priming, fuel pours clean and red. When he runs fuel to rail in clean bucket, fuel is oily looking. He says the oily fuel traces back to secondary fuel filter. This does not have return fuel joining in with supply fuel. Is the high/low pressure pump stack oil lubricated? I don't see it. Is this a common occurrence? I don't have any real world experience with cat equipment engines.

 

[thepumpguysc]

That's a new one..
I'm looking forward to an answer too.

 

[funwithfuel]

Well , if it's new on you, this is gonna be a challenge.
That pump assembly is not oil lubricated is it?

 

[thepumpguysc]

Fuel lubed..

 

[thepumpguysc]

The pumps are noted for the front seals blowing out & putting diesel fuel in the oil but not the other way around..

 

[funwithfuel]

No, no fuel dilution of lube. That was my thought as well. That high psi fuel would migrate to lower pressure lube system vs other way around.
As i said before, it's a friend of mine tackling this . The machine is 4 counties away, and I'm getting info second hand. But I will share as info becomes available.

 

[thepumpguysc]

Yes, please do..
Unless the system has a hi pressure oil pump operating the injectors & the orings on the "tubes" are leaking.. I don't see how its possible.??
Even at that, its a stretch.. IMO

 

[funwithfuel]

That was one of my first questions to him. Make sure we're talking high pressure rail vs HEUI.
He did say that the pump assembly appears to have been heated. The paint is burnt and discolored. I'm supposed to get some pics today when he revisits machine.
Stay tuned

 

[funwithfuel]

Im guessing he didn't get the whole story. Can't imagine what caused this, other than maybe trying to prime a starving fuel system with a case of ether.

 

[thepumpguysc]

Try to pressurize the pump w/ air thru the return..& look for leaks at the front seals..
IF it has a check ball or valve in the return fitting, take it out & pressurize the pump w/ about 3 psi..
NOT MUCH AIR.. spray the front area w/ soapy water or blow it dry & THEN add air..

 

[funwithfuel]

Will that explain the ridiculous heat signatures?
He has already ordered new and is working on getting it going. I just can't believe all that ugliness

 

[Delmer]

Where does that sit in relation to the exhaust manifold? If not an exhaust leak, then siezed bearings is the only thing that would cause that heat and still allow the engine to run.

 

[RZucker]

Where does that sit in relation to the exhaust manifold? If not an exhaust leak, then siezed bearings is the only thing that would cause that heat and still allow the engine to run.

I have seen paint burnt like that from somebody using a torch to "de-gel" a machine.
Is this on a 3126 with a mechanical throttle control? I'm betting a high pressure oil leak is pushing engine oil through the transfer pump seals in to the fuel system. Transfer pump should pull through the primary filter and push fuel through the secondary filter to the head. That should explain the oil in the secondary filter.

 

[funwithfuel]

Sorry, i don't know its relative position, and have not received any more info. My bud got called to another location whivh was more "urgent". I couldn't work like that. Called away mid-job. But that's how his company rolls. I will pass on more as it becomes available.

 

[funwithfuel]

I have seen paint burnt like that from somebody using a torch to "de-gel" a machine.
Is this on a 3126 with a mechanical throttle control? I'm betting a high pressure oil leak is pushing engine oil through the transfer pump seals in to the fuel system. Transfer pump should pull through the primary filter and push fuel through the secondary filter to the head. That should explain the oil in the secondary filter.

Yeah, kinda thought the same thing at first glance, but notice that sticker is just discolored from heat, not burnt. It's as if heat originated in the case, indicating some sort of bearing failure as Delmer suggests. I'm really at a loss.

 

[Cmark]

It's a common rail pump from something like a C7 or a C9. Without even knowing a model, it's all just speculation.

 

[Delmer]

The "oily looking" fuel might be a red herring. If that pump, whatever it is, is that burnt then the fuel residue inside it is burnt as well. Might not have anything to do with the engine oil.

I noticed that sticker, and it sure does look like a "soft heat". The other end by the gear looks like it had a torch left on it near the screwdriver.

 

[funwithfuel]

Looking at the pic again, you can see the lift pump is almost untouched by the heat. But, yeah, I can really see someone getting carried away with a torch at the drive end. Good catch, didn't notice the focused burn spot in all the red.

 

[funwithfuel]

This is where the pump lived and died. No proximity to exhaust or regen system at all.

 

[funwithfuel]

So far, so good. New pump and it's alive.