Other General Tuning Tips (Closed And Open Loop); Tuning And Adjustment Procedures - Holley MPI PRO-JECTION Installation Tuning And Troubleshooting Manual

determined in Data Monitor by observing the Oxy Comp value. The user should make small changes to the map during tuning
and check for the desired results before continuing. Although this tuning procedure results in a slightly rich fuel map, using a
System with an oxygen sensor will correct the actual fuel delivery back to a stoichiometric fuel/air mixture at part throttle settings
to obtain optimum fuel economy.

14.5.2 Other General Tuning Tips (closed and open loop)

1 - Use Mapview to determine which area of the map your engine is operating in.
2 - Use Data Monitor to determine amount of fuel correction by value of Oxy Comp and RPM (closed loop systems only).
3 - Best results are obtained if the engine map is slightly rich (10 - 20%). This value is determined in Data Monitor by
observing the Oxy Comp value (closed loop systems only). To read 20% on the rich side, the Oxy Comp value would
read "-20%" (meaning the map has 20% more fuel than stoichiometric and the ECU is taking out 20% of the fuel).
Conversely, a positive Oxy Comp value (+20%) would indicate a lean point (meaning the map has 20% less fuel than
stoichiometric and the ECU is adding 20% fuel).
4 - Make small changes to the map during tuning. Check desired results before continuing.
5 - Smooth fuel curves as much as possible. Sharp, or even slight transitions in the fuel map can be felt by some drivers.
An example of a smooth fuel curve is shown o the previous page.
6 - If injection duration at idle is around 1700 µsec and the idle fuel delivery is too rich, reduce fuel pressure as outlined in the
testing and adjusting fuel pressure section in the back of this manual. If this method does not increase the injector
duration, then it may be necessary for you to purchase smaller injectors.

14.6 Tuning and Adjustment Procedures

This Section covers the tuning of systems both with and without an oxygen sensor feedback signal. Because much of the tuning
procedure is the same to all system users, only one section has been written. However, paragraphs 6, 9, 11 and 12 can only be
used by systems using an oxygen sensor. These sections should be skipped by a user without an oxygen sensor. Paragraphs
7 and 13 are added to help the user that does not have an oxygen sensor. The beginning of each of these paragraphs will
inform the user to skip that paragraph if necessary. Any paragraph that does not start by specifically stating it only applies to
only one system is intended for both system configurations.
1 - Load the Holley software package into your laptop computer following the procedures outlined above. Connect PC to the
ECU using DB-9 cable provided.
2 - Enter EEprom Programming. Go to the File menu and select Load. Several different fuel maps are provided in the "Load
Map" selection. One of these maps is the base map which is an average of all of the maps and is called Base8.216 there
are 4 maps, choose the one which most closely corresponds to your engine displacement and horsepower. The user can
also choose to use the average map Base8.216 as long as he realizes the average map will be a compromise for his
application and may require more tuning. Make the choice that is most similar to your engine size, highlight the choice
and press "enter". This map will be loaded into the PC. Turn your ignition key to the "on" position and select Send ECU
Map to send the map to the ECU. This will take a few seconds and the screen will prompt you when the programming is
done.
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