Diesel tinkeler

After sitting for some time,upon starting rhe pump leaked around head. Thought Id be ahead buying new pump. Now no leakes but truck doesnt idle as smoth as it did and gets worse as i slowly increase the rpms.
Under power its ***** out. Runs great. Tryed adjusting timing from late enough so wouldnt start to all the way to the head.[real noisey]
What ya thinking?

maybe368

I am not a pump expert, but I would make sure that you have all of the air out of the system and your lift pump may have given up the ghost...Mark

Diesel tinkeler

Iv tried bypassing lift pump with electric to pressurize system to check for leaks.

maybe368

Wouldn't that exclude the lift pump from the leak test? Did you bleed the system with the electric pump running, in order to relieve any air already in the system? If you did, then it is probably not the lift pump, if you didn't it could still be. That also includes any other leak source from the tank to the lift pump...Mark

Diesel tinkeler

Electric pump runs continuous. Steady stream from return line while truck is idling.

maybe368

If there is no air in the system, I still have some doubts, then you are left with either pump or injectors...Mark

Diesel tinkeler

Yup,something is weird. I put new injectors in shortly after.no help. Is there any internal adjustments for low end fuel pressure in pump?

maybe368

That is a question for the pump experts here. They will chime in soon...Mark

nascar mark

One of the problems I see when someone mentions not idling smooth & same when bringing idle up and engine has run for a min or more, so air should be out of system. Sometimes the injector lines are not lined up 100% square on either the delivery valves on inj pump or injectors themselves when line nuts are tightened. Loosen a line nut at a time & move nut back far enough to see if line is lined up perfectly with dv & inj at rest without line nut at all. If not, bend line slightly to be 100% at rest. Seen this engine stumble many times in past & it was just a simple installer error that anyone can do.

MrFusion

I would ditch the diaphragm pump and go with a low pressure piston pump. Less prone to catastrophic failure. I would think that Nascar Mark maybe right though. I had a similar problem and fix to what he described with a Kubota D600 engine.