How to Fix Black Smoke from an EFI Diesel Vehicle?

[MacTanner]

Repair methods for black smoke from an EFI diesel vehicle: 1. Remove the air filter and observe the exhaust smoke color. If the black smoke condition improves, the issue is caused by severe contamination of the air filter; 2. Check if the fuel supply timing is too early and adjust if necessary; 3. During engine operation, conduct a cylinder-by-cylinder fuel cut-off test. When a cylinder is cut off, if the engine speed decreases, black smoke significantly reduces, and knocking sounds weaken or disappear, it indicates excessive fuel supply to that cylinder. Inspect the injector of that cylinder. An EFI diesel vehicle is equipped with an electronically controlled fuel injection and emission diesel engine. The injection system of an EFI diesel engine consists of three parts: sensors, ECU, and actuators. Its task is to electronically control the fuel injection system, enabling real-time control of fuel injection quantity and timing according to operating conditions.