Thread: Specific idling speed fuel consumption 4BDI.

Originally Posted by wagoo

Are there any factory specs for the above?
Bill.

Don't think I have ever seen one Bill. There is a cc figure for the pump plungers but that is not an accurate one for fuel consumption as it doesn't take into account the return fuel. I do know it is next to zilch as I have runup several motors on engine stands from a jerry can and it is hardly noticeable.

Originally Posted by Bearman

Don't think I have ever seen one Bill. There is a cc figure for the pump plungers but that is not an accurate one for fuel consumption as it doesn't take into account the return fuel. I do know it is next to zilch as I have runup several motors on engine stands from a jerry can and it is hardly noticeable.

Thanks Brian. I'll just try a measured quantity someday.
To get me through the holiday period, when I'll be able to afford a dedicated Genset to keep my bank of deep cycle batteries charged, I'll be using the Isuzu with a second alternator.
Bill.

There are calibration figures, John posted them up some time back. Roughly 10mm rack travel and 6.7-9.3 cc/1000 shots.

IIRC idle speed is around 800 rpm, but the torque impulses are not so severe if the idle speed is increased.

Stated fuel figures, cc/1000 strokes and BSFC are commonly based on full load conditions. I will take a closer look at the idle settings when I get a chance later.

In one of my Bosch handbooks they state that the governor has to reduce fuel rate as speed increases - no reason given, perhaps to do with leakage.