Tech Tip Corner
FF409 & FF410 Differences
FF409 & FF410 Differences
While the FF409 and FF410 modules are physically interchangeable their incorrect usage on
the wrong application can result in a hesitation, pinging, or premature coil failure. In
extreme cases engine damage can occur.
The FF409, designed to fit Fords first design TFI-IV module applications incorporates an
internal current limiter to control coil charge time, (dwell). Operating similar to the current
limiter in GM HEI modules, the FF409 depends on primary current ring-back to determine
coil saturation requirements. The effect this has on engine timing is programmed into the
ECA to determine the correct total timing curve.
The FF410 also incorporates this circuitry but has the additional ability to have coil charge
time remotely controlled by the ECA through the timing advance SPOUT lead. This feature
is called Computer Controlled Dwell. The ECA used with this module is programmed with a
different timing advance curve to optimize engine performance.
Dealers mismatching the ECA and Ignition Module take the chance of creating the
previously listed driveability complaints.
Testing for a mismatched ECA-Ignition Module combination can be accomplished by
performing the Ford Computed Timing test. An incorrect ECA-Ignition Module
combination will usually result in a Computed Timing test value outside of the 27-32 degree
BTDC window.
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