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External sensors such as Wideband Air
Fuel ratio, Boost or Fuel pressure will require
additional hardware depending on year model
vehicle and how many external signals you wish
to monitor and/or be included in the TwEECer log
files.
The Ford EEC/PCM is not capable of accessing
these external signals directly, but when
included in your log files, you can quickly see
where a lean condition is and needs to be
corrected.
On
many EEC-IV based vehicles the EGR Valve
Position (EVP) sensor can be used as an analog
input, to measure a 0-5volt signal, much the
same manner as a Digital Volt Meter (DVM).
The output signal of many add on sensors will be
scaled 0-1volt or 0-5volts. This includes
most Wideband Controllers used to accurately
measure Air/Fuel ratios. EEC-V vehicles do
not have this specific extra input available.
The
Original Equipment Manufacturer (OEM) Narrow band HEGO (Heated Exhaust Gas
Oxygen) sensor used by Ford, can measure
Air/Fuel accurately only at stoichiometric or
14.7:1. Outside of that, the accuracy
falls off very quickly, while being able to
report rich or lean, they cannot measure how
rich or lean.
Many
wideband controllers measure Air/Fuel Ratios of
10:1 to 20:1, with some reading a wider range
and others a narrower range. When tuning a
super or turbo charged setup, a wideband is
required, if you want to keep the engine
together.
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