Quick questions for you, on the dirty diesel, what controls the fueling at idle. My understanding is:
MAF is only used when an EGR is in place
MAP sensor determines the air density which in turn determines the fueling - is this at idle for just normal engine running?
Idle Control Valve - the diesel doesn't have one of these
Air temp sensor - as the name states
The reason I ask is that every 60 seconds or so my revs dip on idle and recovers. This doesnt happens when AC is off ( new ac pump has been fitted so not that). I thought it could be a sensor or something. I have a replacement (second hand) 4th injector installed which I hope rules that out as being an issue. Could it be the Crank Position Sensor?