Fast 30400-KIT-EZ-EF, Инструкция по эксплуатации

Страница: 32 / 70

32
RPM Module
EZ-EFI
®
is an advanced fuel injection system. Engine speed is one of the fundamental elements of its
fueling calculations. When not controlling ignition timing, it relies on the vehicle’s existing ignition
system for a steady, reliable RPM signal. An inconsistent or noisy RPM signal can appear to the ECU
as erratic engine speed. Spikes, dropouts and general instability of the RPM signal fed into the ECU
can have an adverse effect on the running of the engine. It can also interfere with proper learning or
prevent learning altogether.
There are two basic options for supplying the EZ-EFI
®
ECU with an RPM input when relying on the
vehicle’s existing ignition system.
1. Aftermarket capacitive discharge (CD) ignition
−
An aftermarket capacitive discharge
(CD) ignition box is recommended. This form of ignition is beneficial to just about any
application. Having a known good, strong spark prevents a host of potential running issues.
This type of ignition is also well suited for use with EZ-EFI
®
because it typically has a
“Tach” output which is a clean digital signal. This is the preferred RPM source for the EZ-
EFI
®
system when it is not controlling timing.
Other aftermarket ignition products besides ignition boxes may also supply a clean digital
tach signal. For example, an aftermarket HEI module with a dedicated tach output (not to be
confused with the “TACH” terminal in the cap of a standard HEI distributor) can be a good
RPM source for the EZ-EFI
®
system.
If using one of these ignitions, the “RPM INPUT” wire in the EZ-EFI
®
wiring harness is
connected directly to the “Tach” output from the ignition box. The RPM Module included
with the kit is not used in this case. And no part of the EZ-EFI
®
system is connected to the
coil.
NOTE: Some aftermarket ignitions have a feature for displaying their programmed rev limit.
This is accomplished by briefly outputting an RPM signal on their tach output wire soon after
key-on. The intent is to have the vehicle’s tachometer display the rev limit setting. This
feature is not well suited for some fuel injection systems – including EZ-EFI
®
– as it appears
the engine is actually running at that speed. This can lead to the ECU rapidly pulsing the
injectors (injecting a large quantity of fuel) and flooding the engine. Contact your ignition
vendor to verify whether or not your ignition product has this feature and for details on