High Idle on 7MGTE - TPS Out of Spec Causing Code 51 and Timing Advance

Engineintermediate✓ OP Confirmed

Problem

7MGTE idles at 1100-1500 RPM instead of the target 750 RPM. Idle varies with engine and ambient temperature, starting around 1500 RPM cold and settling to 1200 RPM warm.

High idle at 1100-1500 RPM when warmed upIdle does not drop to normal 750 RPMPinching IACV hose does not stall engine (indicating vacuum leak or excess bypass air)Timing read 20-25 degrees instead of 10 degrees BTDCECU continuously flashing code 51 (TPS IDL signal fault) even with engine offStrong vacuum felt at throttle body inlet when throttle plate closedIdle varies with engine and ambient temperature

Root Cause

Multiple contributing issues: (1) TPS was out of spec on the 0.5mm IDL-E2 contact test, causing a continuous ECU code 51 which advanced ignition timing to 20-25 degrees, raising idle significantly. (2) Cracked fuel injector grommets in the head were causing vacuum leaks. (3) A worn groove in the throttle body actuator cam prevented the throttle plate from fully closing on its own.

Confidence

Moderate confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted April 2022 on SupraForums.com