very sad question

[99bigred]

i feel like such a noob....but ive never been sure if the hpop pumps engine oil or diesel? both? and how does the fuel injection system use high pressure engine oil?
thanks

[huhner5]

I am also interested... never really have heard for sure... I feel Dumb

[mschn99]

the low pressure oil pump feeds the motor just like any pump. It also feeds the high pressure oil pump..

the high pressure oil pump feeds high pressure oil to the injectors...this is controlled by the IPR (injection pressure regulator) valve and the pressure is measured by the ICP sensor (injection controll pressure).....

the oil in the injector forces a pistion down..which multiplies its pressure and injects the oil at a VERY high pressure......

[99bigred]

so there really is no high pressure diesel pump like the old machanically injected diesels? only the electric one on the frame rail?
these questions have always bothered me but felt dumb to ask
thanks for clearing things up

[cebulmer1]

Hey there is never a sad or dumb question. Just remember "A mouth closed is a mouth unfead"

[99bigred]

ya it was just funny it seems that everybody knows what an HPOP is and the only other diesel i ever worked on was a 94chevy and it had a high pressure diesel pump in about the same area so i assumed it was the same thing. then i start reading more and it said it need engine oil and i got real confused.
but thanks for clearing things up...should have know nobody on this forum would laugh at a "sad question"

[ABOBB]

To add a little to what Marc said earlier... the HEUI system does not use a high pressure fuel supply. The injectors, through the use of the high pressure oil, and either an intensifier piston or a spool valve (depending on 7.3 or 6.0) pressurizes the fuel prior to introducing it to the combustion chamber.