It's What's on the inside that counts

While every part of a fuel injection pump is important, the interior is where the action happens. Despite a small footprint, dozens of moving parts all must function cohesively to get the exact fuel mixture injected when your engine needs it.  If one component isn't working or was incorrectly adjusted, countless issues and symptoms will arise and prevent your classic car from functioning properly, if it runs at all.

Here we'll give you a jump-start on understanding the body and inner-workings of the Bosch fuel injection pump.

The featured illustration displays the linkage (green) between the rocker (red) and correction lever (orange), along with their relationship to the aneroid (light blue) and control valve (dark blue). 

The photographs below show the location of each part in relation to running temperature with -20°C on the left followed by 20°C, 40°C, and warm-running. In the final image on the right, while running at warm temperatures, you can see the correction lever is almost parallel to the bottom of the housing opening, the correction lever pin is centered on the guide roller, and the spring to the left is fully compressed meaning no air is being allowed through the control valve.