Changes for Large injectors on the L series EEC
If you run larger injectors, there are a few changes to be made.
If you are running an injector larger than 57pph, you will need to change the following parameters (known as 2X injectors):
P_1178 Injector size - half actual size of injector
P_1C2B - half the vale for the tripminder
P_2ADC - double value
P_2E69 - double value
P_30F0 - half the value
F_04FC Crank fuel vs ECT - Using the example of a
55pph injector, reduce the crank fuel by dividing the original injector by the
new injector (35/55=0.7) and multiplying (0.7) by the crank fuel value. Black
values are the modified and blue values are stock.
The formula works ok when do not have the adjusted the parameters for 2X.
When you have 2X injector mods, divide the injector by 2 then divide by the original injector. Example: if you have 85pph injectors, (35/42.5=0.823) - Still testing
EEC initialization injector PW and the startup fuel adder
One way to decrease the strategy's calculated fuel pulsewidth is to
increase the strategy's target air/fuel ratio. The base target
air/fuel ratio is 14.64 to 1. If you double the target air/fuel
ratio to 29.28:1 then the strategy's calculated fuel pulsewidth will
be cut in half. With the target air/fuel ratio doubled and the
injector size (F_0C20/PE , F_04FC/LA3) calibrated to 35#/hr, the
strategy should calculate the proper fuel pulsewidth for if you had
70#/hr injectors installed. This trick should enable the
installation of larger injectors than the strategy is currently
designed to handle.
Warning: I have never changed the target air/fuel ratio myself, but
in principle it should work.
The latest RDT files should have the proper location and scaling of
the target air/fuel ratio. (P_241D/PE , P_2ADC/LA3). There is
another parameter change that will also be necessary. If
(P_241D/PE , P_2ADC/LA3) is changed then parameter (P_277E/PE,
P_30F0/LA3) will also need to be changed by the same ratio as the
target air/fuel ratio.
One feature of the PE/LA3 strategies is that changing the injector
size (P_04B2/PE, P_1178/LA3) in the calibration does not have any
effect on the length of the cranking fuel pulsewidth.
Whenever injectors are changed the crank fuel function should be
recalibrated (F_0C20/PE , F_04FC/LA3). I would guess that doubling
the actual injector size might half the desired crank fuel
pulsewidth at every Engine Coolant Temperature.