TECHNICAL NOTES ON THE EEC-IV MCU - Auto diagnostics

Eectch98-Part5.fm
· Boost Retard Subtractor: Retards spark in degrees per lb. of boost based on rpm.
· Nitrous Spark Retard Subtractor: Retards spark during nitrous oxide operation (two
stages).
· Programmable Output Spark Adder/Subtractor: Advances or retards spark based on the
output state of each programmable output channel. You select what device these channels
are connected to.
· Analog Input Spark Adder/Subtractor: Advances or retards spark based on the input
voltage of each analog input channel. You decide what device to connect to these
channels.
EPEC offers a 16-channel data logger that is fully programmable, so you can choose
what data to log, at what time, for how long and through which limits. The amount of
memory in the EPEC is limited, of course, so the more functions logged and the
longer information is logged, the fewer data points and the slower the hertz (points
per second) you’ll get. There is plenty of memory for logging drag strip runs in
useful time frames with many parameters, however. Essentially any data the EEC
takes in can be logged, plus whatever you hook to the four programmable outputs and
three analog inputs. By looking at things like the mass air meter and oxygen sensor
signals, along with the usual rpm measurements, interesting phenomenon and correlations
can be seen.
Because EPEC is already monitoring rpm and has its own clock, it’s a cinch to let it
control nitrous solenoids or other time/rpm dependent gear. Thus it makes a fullfunction
nitrous controller. There’s also a spare I/O wire from EPEC which can turn
on something as simple as a bulb (Make your own shift light?), or any other device.
Sam believes racers will use it to turn on a second data logger rigged to chassis
inputs such as driveshaft speed, suspension travel and so on.
EPEC can also perform all ignition boost retard functions. This requires a MAP sensor
(also useful for data logging). It recognizes the common GM MAP sensor, so the
hardware is easily available. EPEC can also easily handle rev-limiting duties under
its regular menu, including two-step functions.
Source:
Ford Motorsport SVO
44050 N. Groesbeck Highway
Clinton Township, MI 48036-1108
(810) 468-1356
EEC-IV Technical Notes: Modifications/Upgrades71 last edited: 9/29/98