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
Scan tool displays
-25 - +20 percent. Long Term Fuel Trim is derived from the Short Term Fuel Trim value and represents a long-term correction of fuel delivery. A value of
0 percent indicates that fuel delivery requires no compensation in order to maintain the
PCM commanded air-to-fuel ratio. A negative value significantly below
0 percent indicates that the fuel system is rich and the fuel delivery is being reduced. This condition is represented by a decreased injector pulse width. A positive value significantly more than
0 percent indicates that a lean condition exists and the PCM is compensating by adding fuel. This represents an increased injector pulse width. Because Long Term Fuel Trim tends to follow Short Term Fuel Trim, a value in the negative range due to canister purge at idle should not be considered unusual. The maximum authority of the PCM to control long term fuel trim allows a range of
-27 - +27 percent. Fuel trim values at or near the maximum authority may indicate an excessively rich or lean system.