LR
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EngineHigh severity

Oil wicking up the injector harness into the ECU

Safety or reliability risk. Fix promptly.

Symptoms

Oil found in the injector harness plug at the cylinder head, oil in the ECU connector, misfires, poor running or stalling.

Likely cause

Engine oil seeps along the copper conductors of the injector loom from under the rocker cover, eventually reaching the ECU.

Suggested fixes

Listed roughly in the order most owners try them.

  1. 1

    Replace the internal injector harness and plug seal

    Remove the rocker cover and fit a new internal loom and seal where it exits the head.

    Difficulty:
    Moderate DIY
    Cost:
    £ (Under about £50 in parts)
  2. 2

    Fit an anti-wick pigtail lead

    A short pigtail between the engine and the main loom breaks the path for oil so it cannot reach the ECU.

    Difficulty:
    Easy DIY
    Cost:
    £ (Under about £50 in parts)
  3. 3

    Clean or replace the main loom and ECU plug

    If oil has already reached the ECU, clean the connectors with electrical cleaner, or replace the engine harness.

    Difficulty:
    Moderate DIY
    Cost:
    ££ (About £50 to £300)

This is general guidance gathered from owner experience and workshop practice, not a substitute for a workshop manual or a qualified mechanic. Costs are rough parts-only guides. Brakes, steering and suspension work affects safety, so if in doubt have it checked professionally.

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