[QUOTE=Charlie;828069]I just want to get this straight. The red lines represent the fuel flow if the seals are bad
in the injection pump.
If I disconnect the lube oil line while the engine is running it will make a mess, but the diesel should be easy to spot
and if I shut the engine down before
disconnecting the lube oil line and capture the fluid that comes out from the lube oil line I will know if the injection pump is leaking and not destroy the engine. There would be fuel in the line vs lube oil.
OTOH if the lift
pump is bypassed from the system and the engine does not make oil that also eliminates the injection pump as a source for oil dilution Yes
and the only other option would be that the injectors are leaking fuel into the cylinders. This is unlikely b/c my engine does not throw out smoke.
If the injector is leaking after shutdown, from residual pressure, then it would just drain past the piston while sitting. The amount of oil would depend on how many start ups & stops.
I might add; if the lift pump is leaking there needs to be enough pressure to over come the 100 psi oil pressure (when cold). So, in some cases it may be just leaking from gravity or back pressure into the lube line while the motor
is off. Does your electric pump shut off with the motor?
If you look at the pump specs chart I posted it shows 2.9 psi for the lift pump, not enough to over come the oil pressure, unless the injection pump is leaking just enough to force fuel backwards. In that case it could be both, with the injection pump only leaking slightly or creating some sort of pressure in the cam cavity (heat or motion).
It's really hard to nail it down w/o being there to open up systems to see what's going on. The only other way for fuel to get into the crankcase is past the pistons!