Something new. Under the vacuum pump, on the front left side (when looking from the front), is where you can find the shutter valve/anti-shudder valve. It looks like a throttle valve, but CDIs don't actually have any. Its sole purpose is to create a vacuum when the engine is turned off (thus eliminating the thump heard on older diesels) and, on occasion, to partially close (again, to aid EGR flow), so that the engine does not overheat. The derv engine's speed is mostly unrestricted because the only controls are the duration and pressure of the injectors, not a throttle. A spray hole would be created by the easily detachable air intake temperature sensor located on the rear of the device.