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 range is
-23 to
+16 percent. The long term fuel trim is derived from the short term fuel trim value. This represents a long term correction of the fuel delivery. A value of
0 percent indicates that fuel delivery requires no compensation in order to maintain the
PCM commanded air/fuel ratio. A negative value significantly below
0 percent indicates that the fuel system is rich and fuel delivery is being reduced, 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, increased injector pulse width. Because long term fuel trim tends to follow short term fuel trim, a value in the negative range due to the canister purge at idle should not be considered unusual. The PCMs maximum authority to control long term fuel trim allows a range between
-23 percent and
+16 percent. Fuel trim values at maximum authority may indicate an excessively rich or lean system.