Rio Cinco L4-1.6L DOHC 16V (2003)
Throttle Body: Technical Service Bulletins
Fuel System - Throttle Body Cleaning Procedure
VOLUME
3
GROUP
Fuel
NUMBER
010
MODEL
All
DATE
September 2005
SUBJECT:
THROTTLE BODY CLEANING
This bulletin provides information relating to throttle body and plate cleaning on all Kia models. Residue from fuel additives and/or carbon deposits that
result from normal fuel combustion can accumulate on the throttle body and/or upper combustion chamber over time. Dirty throttle bodies can cause a
variety of vehicle drivability concerns and may result in MIL illumination under certain circumstances.
When the engine is started, the incoming air sometimes carries residue back to the throttle body and deposits it just behind the throttle plate because of
the sudden drop in air pressure behind the plate.
When the engine is running, crankcase vapors enter through the PCV system and work their way into the intake system. These vapors carry with them
residue which accumulates on the idle passages and throttle plate. This build-up eventually blocks the air gap between the throttle plate and throttle body
bore, causing less airflow while the throttle plate is closed. Over time, the computer compensates for the reduced airflow with fuel trim adaptive logic
adjustments, as it becomes more difficult for the computer to control the idle, especially when coming to a stop or when the throttle is "snapped". Do
NOT replace the throttle body before the throttle plates are cleaned for any condition related to fuel trim values.