If you move the top of the pump forwards or backward you will either increase fuelling and engine RPM will rise or decrease fuelling and engine RPM will drop. Simple as that. You are moving the control collar backwards or forwards along the piston therefore giving more or less fuel. This would only be needed if the top half of the pump has been removed to restore idle to 750 RPM.
It's not that simple. You are not moving control collar directly!
It's the ECU that decides to move control collar and set desired RPM. By moving top of the pump you only alter minimum and maximim achievable fuelling. But if you go beyond limits, then the ECU has problems with controlling fueling.
Done that many times(on Range Rovers and BMW), idle RPM never moved during adjustment procedure.
I would also add, that diesels have tendency to runaway with constant fuel rate and low load, thats why injection pump governors were introduced years ago.
In fact, those electronic pumps are very simple, far more simplier than those with mechanical/hydraulic governor.
Just set hot engine fuelling between 4-6mg/stroke and if fuel temperature sensor is working as it should, it will be ok.
EDC were the early ones with potentiometer(fuer return facing upwards on top cover) - discontinued somewhere 1995-1996 - it wasn't repairable once potentiometer traces worn, new pump top not avalible anymore, even at BOSCH.
HDK with fuel return facing backwards. Mine is MY98 and its HDK pump top.
Don't know why, but RAVE does not cover HDK version.
P38 diesels have VE-EDC pumps not VE-HDK pumps. I do know a tiny bit about diesels.
I don't!
What's the difference?
did you ever sort this ?Hi all can anyone help I've recently bought a automatic p38 with the 2.5 bmw engine and noticed it seems very slow to accelerate in first once turbo kicks in she's fine also very slow in reverse I left a friends work shop today he's at the bottom of a slope and rangerover would not go up it in reverse it started to but stopped even with my foot hard to the floor it wouldn't move had to spin around and drive out I know they aren't fast but old ladies in mobility scooters are beating me of the lights power steering pump has died Aswell !!!! Any advice cheers will from Norwich