Ford Programmable ECU

[Daniel Ciobota]

OK, the title is a bit of a misnomer, the unit actually modifies the existing
ECU's signals.  For those of you who have asked about the unit, here's all the
info I have:

I purchased the unit used.  It is equivalent (though not completely identical)
to the Anderson PMS unit featured in one of the stangs mags last month.  The
current price for the unit is $749.00 with the data logging software an extra
$249.00.  It's pricey, and I would never pay that much for it myself.

Functionally, the unit plugs into the factory computer, and the existing
factory computer harness plugs into it.  There is a serial port to communicate
with a handheld terminal (kinda difficult to use at first) or, with the
interacq data logging software, with a laptop.  It also has provisions for two
extra 0-5v inputs for monitoring and two 12v switches for activating external
devices, like nitrous switches and such.  You use the handheld terminal to
monitor a few inputs and reprogram the ecu fuel and timing tables.  The laptop
software has additional monitoring capability and can also download and upload
saved tables; however, it does not offer programming capability for the
tables.
The handlheld unit can handle three different programmable data sets
(fuel/timing tables) and can switch between the three at any time.  Thus, you
can have a set programmed for economy, one for drag, one for emissions
testing.  The makers of my unit claimed that it was for off-road use only, as
you could reprogram the tables to become non-emissions compliant; but, since
the unit is pretty well hidden under the carpet and passenger seat, most
inspectors won't bother to get that thorough.

How the unit reprograms the ecu.  The stock ecu computes engine load based on
throttle position and airflow.  To the ford ecu, the load falls into three
major modes: idle, part throttle and full throttle (wot).  Under part
throttle, there are three engine load modes as well: low, medium and high.
This makes a total of 5 engine loads where fuel and timing can be altered.
For each engine load, there are also three rpm points where the fuel and
timing can be changed; in between those points, the fuel and timing values are
linearly interpolated.  So, there are a total of 15 points where the fuel and
timing values can be changed, with all other points in between being
interpolated.  There is also an rpm extender feature that allows fuel and
timing tables to be extended past the stock ecu limit (6250rpm), but it gets
more complex, perhaps needlessly so imo.  One more item to note is that the
fuel and timing values entered in the table are not absolute, but differences
between the stock ecu value and desired value.

When you edit a data set, the terminal makes a copy of it in ram and uses it
as the current data set.  Thus, any changes you make have immediate effect.
It was kinda neat to play with idle fuel and listen to the exhaust difference
between a rich and a lean mixture; you can actually tell by sound at which
mixture the engine idles best.  As with  most fords, the stock ecu ran way
rich; leaning it out got rid of a lot of roughness and surging.

Now, the guts...  I took apart the handheld programmer and to my dismay most
of the chips are hidden under the entry pad, except for the eeprom, which has
a large label on it.  The eeproms on both the main controller box and the
handheld unit had to be replaced when I upgraded to the data logging software,
since they apparently need more memory.  The old chips are 2764's (nm27c64q,
to be exact) which I think are 64k chips, right? Haven't looked at chip
designations in a while.  I haven't gotten around to unboxing the main
controller but I will do so whenever I can.  I've gotten overloaded with
projects lately.


Last but not least, the pc software.  As I mentioned, the software connects
with the main controller over the serial port and is able to log about 20
pieces of data at about 5-10hz.  The code is dos based (yuck!) but has some
nice graphics on it to display rpm, fuel and so on.  among the 20 variables
recorded are rpm, throttle position in percent, tps value in volts, left and
right o2 readings in volts, air temp, water temp, in/out fuel pw/duty cycle,
in/out total timing, maf reading in volts and lbs/min, map reading (on
speed/density cas only) in volts and inches hg, computed load, and more.  You
can replay either the currently logged set (only 4195 records max, about
12min) or a saved one.  You can also monitor most of the variables while
recording.  The logs are saved in binaries, with a conversion utility to
produce an ascii file.  I also wrote some code that post-processes this ascii
file to reformat the data and calculate things like rear wheel torque and
horsepower, given some additional car info.  One other utility of more
interest to you and me as well can load the currently running tables from the
controller to the laptop and vice-versa.  The data is in binary format, but I
think if I start with a reference and change one table item at a time, I can
probably figure out the format.  Again, I haven't had a chance to do that yet.

And that's enough for today lecture, boys and girls... :-)

Anyhoo, there are a few more products slated to be on sale "real-soon-now" for
the ford eec-iv crowd.  One is Mike Wesley's Calibrator, which is an improved
version of what I have (sans data logging, available in a later version for
more money) and is laptop programmable, at $415 current price. Another is the
Ford Motorsport EPEC, which is kinda pricey at $1300 but has a windows
interface and much more flexibility than my unit.

Feel free to ask me more specific questions, and I'll to my best to answer
them.  Currently I'm still learning how to tune the car with this stuff, so
I'm no expert by any means.

Daniel