stone@kvue.UUCP (Anthony Stone) (02/11/85)
A company in California led by engineer Glen Cunningham has cracked the
Delco/GM computer codes and have "reversed engineered" nearly all of the GM
car computer systems, so says an article in this month's Hot Rod magazine.
The company, Digital Automotive Systems of Garden Grove, has introduced
a hand-held engine analysis and diagnostic module called the Conquest,
which plugs into the GM Electronic Control Module in place of the PROM
which calibrates the generic ECM to a particular model car.
According to Hot Rod, GM engineers can't figure out how this works and
Cunningham isn't telling.
The unit, which resembles a large pocket calculator with 16-button pad
and LCD display, lets the user continuously examine the settings of 19
input/output sensors and switches, plus read out engine information such as
vacuum in psi, inches of mercury and kiloPascals.
But as they said on the Ronco commercials,"How much would you pay for
this? Well, that's not all!" The Conquest unit allows the users to *change*
any of the engine functions with the keypad. Want to change idle speed?
Call up idle rpm and push "up" or "down." The same can be done with spark
advance or fuel mixture. You can also turn off any sensors in the system,
like EGR and AIR. (Yes, I know this affects emission control. Flames to
the manufacturer, not me.)
This first unit is designed for shop use and therefore expensive. This
summer, DAS intends to offer a smaller, more-affordable unit that can be
permanently mounted in the vehicle.
Another company, Papile's Performance Systems of Santa Ana, offers a
complete replacement for the GM computer. It optimizes fuel delivery,
recurves ignition advance, delays torque-converter lock-up on automatics,
and turns off smog controls. A dash-mounted control panel allows the driver
to manually switch from closed loop mixture control (where an oxygen sensor
in the exhaust is placed in a feedback loop with the carburetor,
optimizing emissions for pollution control) to open loop mode (where the
mixture is based on other sensors). You can also lock/unlock the torque-
converter clutch and change spark advance from the dash.
Is all this just another gimmick to keep the Saturday mechanic busy?
Hot Rod will publish details next month on their test of the Papile unit
on an otherwise stock '84 Z28 and S10 blazer, where a 10-15% increase in
both performance and economy was noted.
Each of the big three automakers is also offering "aftermarket" computer
ignition upgrades, and the article describes them as well as the amazing
new sensors that have been developed to provide input to these computer
systems. There's also mention of an "adaptive learning" capability
common to all the latest car computers. While it's not AI for cars, it's a
step in that direction. "If the computer sees that the engine continually
tends to run lean, say, when climbing a grade at 55mph, it will remember
this condition and adjust for it (this is why new cars have to be driven a
little before the computer `dials itself in.')" If the computer fails, you
get a "limp home mode" where the system goes to a full rich setting with
retarded spark. It's better than previous systems, which only had the
"stranded mode."
Anyway, has anyone had any interesting experiences with the new auto
control computers, whether modifying them, bypassing them in the event of
an emergency or installing the new "performance" models? Anyone know the
details such as microprocessor type (custom, I'd bet), memory (any use
of EEPROM?), automatic testing, etc.? Have there been any software bugs?
(broken pipes? :-)
---------
Anthony Stone
KVUE-TV
{ihnp4,seismo,gatech,ctvax,nbires,ucb-vax}!ut-sally!kvue!stone