High Pressure Fuel Pumps: Notes
| ITEM | DESCRIPTION |
|---|---|
| 1 | Crankshaft |
| 2 | Auxiliary drive chain |
| 3 | Auxiliary camshaft |
| 4 | Tappet |
| 5 | High Pressure (HP) fuel pump - No. 2 (Rear) |
| 6 | Acoustic cover |
The two HP fuel pumps are identical mechanically-driven pumps installed on the right side of the sump body, behind the generator. An O-ring seals each of the HP fuel pumps in the sump body. The front fuel pump is identified as No. 1 HP pump; the rear fuel pump is identified as No. 2 HP pump. An acoustic cover is installed on each of the HP fuel pumps.
The HP fuel pumps are single-plunger pumps. The plunger of each pump extends through the sump body and the carrier of the auxiliary camshaft. A tappet on the end each plunger is operated by a two-lobe cam on the auxiliary camshaft. A spring installed on the outside of the plunger ensures the plunger and tappet remain in contact with the cam.
The auxiliary camshaft is driven by the crankshaft, via the auxiliary drive chain, at engine speed. The auxiliary camshaft is timed to match the pump delivery strokes with crankshaft position.