So maybe you guys know this already but I was wondering what the actual signal was. I don't have the oscilloscope that would make this easier to simply look at pins for, but here it is:
The Data Output Link (DOL) provides a communication line between the EEC and
the vehicle dashboard computer, Tripminder, for the transfer of fuel
consumption information. The fuel flow information sent by the EEC is used
for computation of instantaneous and average fuel economy, which is then
displayed to the driver.
The Tripminder requires an appropriate integer number of pulses within 100
msec period. Therefore, within each background loop or each 100 msec period,
whichever is shorter, the EEC sums the fuel flow and through the injectors
output since the summing period started, converts this sum into DOL pulses,
and outputs these pulses at a maximum frequency of 500 Hz during the
following summation period.
The fuel flow is converted into DOL pulses according to the following
equation:
DOL_COUNT = INTEGER (FUEL_SUM * 7804.19 * INJOUT) + DOL_COUNT
The FUEL_SUM is then reduced by the amount converted into DOL_COUNTS (One
DOL_COUNT = 1.282E-4 lbm).
where,
DOL_COUNT = Number of pulses to be output beginning
in the next summation period. One
DOL_COUNT = 1.282E-4 lbm.
FUEL_SUM = Sum of fuel flow per injector, which was
initiated since last summation period. It is
updated during the Fuel PW output routine.
7804.19 = (48000 pulses/gal)/6.15 lbm/gal, pulses/lmb.
INJOUT = Number of injectors per output port.
(See Fuel Strategy)
14-2 DATA OUTPUT LINK - GXK0
PEDD-PTOPE, FoMoCo, PROPRIETARY & CONFIDENTIAL
FUEL_SUM = FUEL_SUM + LBMF_INJn
LBMF_INJn = Fuel Flow per injector, calculated from
FUELFLOWn (n= 1, 2). (See Fuel Strategy).
---- ---- ---- ---- ---- ----
| | | | | | | | | | | |
| | | | | | | | | | | |
FUELPW ----- ----- ----- ----- ----- ------
|<-- 1 BACKGROUND LOOP -->|----
|| |
|| |
DOL | |
OUTPUT --------------------------- ------------------------
