On DDEC III/IV engines there is an Air Temperature Sensor (ATS) mounted to the bottom of the inlet elbow. The ATS sends an electrical signal to the ECM indicating the inlet manifold temperature of the air entering the engine. The ECM uses this information to adjust gas flow, control air fuel ratio and in some cases fan control. The ATS provides necessary input to vary hot idle speed and injection timing resulting in improved cold starts and reduced white smoke.
| 1. Fuel Temperature Sensor | 5. Air Inlet Elbow |
| 2. PSV | 6. Low Pressure Regulator |
| 3. Fuel Mixer | 7. Air Temperature Sensor |
| 4. Throttle | 8. Fuel Pressure Sensor |
| | 9. Fuel Inlet Tee-Fitting |
