Manuals through 2025 now available!
Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.
LEMON is the spiritual successor to CHARM, I recommend you try it!
Link:
lemon-manuals.la or
lemon-manuals.org.ua
(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)
Or, hide this message:
temporarily or
permanently
Long Term FT
The scan tool displays a positive or a negative percentage. The
PCM derives the Long Term Fuel Trim
(FT) from the Short Term Fuel Trim value. The Long Term Fuel Trim represents a long-term correction of fuel delivery. A value of
0 percent indicates that the fuel delivery requires no compensation in order to maintain the PCM commanded air/fuel ratio. A negative value significantly less than
0 percent indicates that the fuel system is rich and the PCM is reducing the fuel delivery (decreasing the
fuel injector pulse width). A positive value significantly more than
0 percent indicates that a lean condition exists and the PCM compensates by adding fuel (increasing fuel injector pulse width). Fuel trim values at maximum authority may indicate an excessively rich or lean system.