📘 ECU Knowledge Base
Comprehensive technical documentation on ECU systems, torque models, emissions logic, sensors, maps and safe calibration procedures.
OBD System & Readiness
On-Board Diagnostics (OBD) monitors emissions-related systems and reports faults. Readiness monitors must complete for emissions testing compliance.
Overboost Protection
Overboost protection prevents excessive turbo pressure that could damage the engine, turbocharger or intercooler. The ECU responds with torque reduction or fuel cut.
Oxygen Sensors (Lambda)
Oxygen sensors measure exhaust gas oxygen content for AFR control and catalyst monitoring. Critical for fuel management and emissions compliance.
Pilot Injection
Pilot injection delivers a small fuel quantity before the main injection to reduce combustion noise and improve cold start behavior in diesel engines.
Post Injection
Post injection delivers fuel after the main combustion event to support DPF regeneration and reduce hydrocarbon emissions during warm-up.
Rail Pressure Maps and Limiters
Detailed view of rail pressure target maps, security caps, ramp behavior and pump protection in common-rail diesel systems.
Rail Pressure Strategy
Common-rail pressure control ensures precise fuel atomization and engine efficiency. EDC17/MG1 ECUs use multi-loop control to regulate pressure based on torque demand.
Reading and Interpreting ECU Logs for Tuning
Which channels to log during tuning: boost, IQ, rail, lambda, EGT, knock, torque.
Rev Limiter
The rev limiter prevents engine over-revving by cutting fuel or ignition above a threshold RPM. Protects valvetrain, pistons and bearings from damage.
Safe Tuning Workflow: From Stock to Stage 1
Order of operations for safe diesel/gasoline tuning: airpath → smoke → torque → IQ → rail → SOI → validation.
SCR / AdBlue System
Selective Catalytic Reduction (SCR) uses AdBlue injection to convert NOx into nitrogen and water. Essential for Euro 6 diesel compliance.
Secondary Air System
Secondary air injection pumps fresh air into the exhaust during cold start to accelerate catalyst light-off and reduce HC/CO emissions.
Sensor Plausibility Checks and Cross-Checks
How ECUs cross-check MAF vs MAP, EGT vs load, NOx consistency.
Smoke Limiter
The smoke limiter prevents excessive black smoke by limiting injection quantity relative to available air mass. Critical for emissions and DPF health.
Speed Limiter
The speed limiter caps maximum vehicle velocity by reducing torque or fuel cut. Often set at 250 km/h for European vehicles, modifiable in ECU calibration.
Stage 2 and Hardware Upgrades
What changes when upgrading turbo, injectors, exhaust, intake.
Start of Injection (SOI)
Start of Injection timing determines when fuel enters the combustion chamber. SOI directly affects power output, emissions, noise and engine stress.
Swirl Flaps
Swirl flaps create turbulence in the intake manifold to improve air-fuel mixing at low RPM. ECU controls their position based on operating conditions.
Thermal Protection
Thermal protection reduces engine output when temperatures exceed safe limits. Protects pistons, turbo, exhaust components and catalysts from heat damage.
Throttle Control
Electronic throttle control (ETC) manages airflow to the engine via drive-by-wire systems. The ECU interprets driver demand and applies torque-based control.
Torque Limiters
Torque limiters cap engine output based on conditions like gear, temperature, and component protection. Critical calibration targets for performance tuning.
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