Quick answers. Fast fixes.

1) Flashing / ECU issues

ECU won’t connect

• Check cable drivers (OBDLink EX or Tactrix OpenPort).
• Ignition ON (engine OFF) during connection.
• Try different USB port, disable sleep/antivirus.

Flash failed mid-write

• Don’t panic. Retry with battery charger connected.
• Always keep a backup of stock file.
• Most ECUs recover if flash is restarted correctly.

2) Limp mode / CEL after mods

Common triggers

• MAF scaling mismatch (wrong intake diameter).
• Boost cut exceeded (MAP reads above ECU limit).
• Cam/crank sync error after mechanical changes.

Quick checks

• Scan DTCs (don’t guess — codes point the way).
• Check live trims, AFR, boost sensor readings.
• Look for vacuum/boost leaks, loose connectors.

3) Fuel cut / Boost cut

Fuel cut

• Occurs when injectors max or ECU protection triggers.
• Fix: larger injectors, higher flow pump, rescale maps.

Boost cut

• Triggered when MAP > ECU limit (stock ~1.5 bar abs).
• Fix: install 3-bar MAP, rescale ECU, set safe cut.

4) Knock & fuel trims

Knock activity

• High IAT/ECT, poor fuel quality, or too much timing.
• Check logs for correlation — don’t rely on one blip.

Fuel trims off

• STFT/LTFT outside ±10% → vacuum leak, MAF error, injector scaling off.
• Reset ECU after fixes, re-log trims at idle & cruise.

5) Drivability issues

Idle hunting

• Air leak, incorrect VCT target, or aggressive cams.
• Check idle control valve duty & trims.

Misfire under load

• Spark plug gap too wide, weak coils, or lean fueling.
• Close gap (0.6–0.7 mm turbo), check dwell maps.

Jerky throttle

• Throttle body adaptation needed after flash.
• MAF curve transition too sharp → rescale smoother.

6) General FAQ

Can I always return to stock?

Yes — as long as you saved the stock ECU file before first flash.

How often should I log?

At least once per season or after major mods. Logs catch small issues before they become failures.

What’s the #1 cause of problems?

Weak electrical supply during flashing or tuning. Always stabilize voltage.