Pontiac GTO Forum banner
1 - 1 of 1 Posts

·
Registered
Joined
·
418 Posts
Injector Slope
Use to determine the injector size and also to correct the long term fuel trims.

* Injector change: To properly set up injector size it is recommended that you multiply the current slope by injector % change.
Example:
#24 to #30
(30-24) / 24 * 100 = 25%
so multiply the entire slope by 25% to get you in the ballpark.
* Determining long term fuel trims: Long term fuel trims are an accumulated value of fuel added or subtracted during closed loop operation.

To verify and tune for long term fuel trims, drive the vehicle for 30 minutes or until warmed up, monitor long term fuel trims and get an average value. The easiest way to do this is to get on the highway, enable cruise control and sit at 55mph while monitoring the data. Ideal values should be in the 0 to negative 2 range.
* Once you get the average long term fuel trim value:
o Positive long term fuel trims
For a positive value you subtract that value in percent in the predator injector slope. It is also recommended to lean both fuel tables by the same percentage.
o Negative long term fuel trims
For a negative value you add that value in percent in the predator injector slope. It is also recommended to richen both fuel tables by that same percentage.

Once adjustment is done and tune installed, take the vehicle out and verify the long term fuel trims per previously described method. Adjust again if necessary.
 
1 - 1 of 1 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top