The
following questions should be answered to the best
of your ability. Some information may not require
an answer if your motor is stock. The more
information understood the better optimized your
programming will be.
#1. Cubic
displacement IE: 305, 350, 355, 383, 406, etc.
#2.
Transmission type: Automatic, or manual.
#3.
Compression ratio and cylinder head type.
#4. Cam
specifications: Duration & lift @ .050 &
Lobe separation angle (LSA)
#5.
Injector size: Brand & number preferred.
#6. Fuel
rail number IE: 1708XXXX, or if using an
adjustable pressure regulator? What is the desired
pressure at idle with vacuum disconnected. I will
recommend if asked.
#7.
Vehicle Anti Theft System (VATS): Enable / Disable
#8.
Exhaust gas recirculation (EGR): Enable / Disable
#9 Vehicle
Speed Sensor (VSS): Enable / Disable.
#10.
Cooling fan(s) settings: 160, 180, or 195. I
recommend using at least a 180 thermostat for TPI.
#11. Speed
limiter: Default is 255 mph / or specify desired
speed.
#12. RPM
limiter: Default is 10,000 RPM / I recommend
limiting it to 800 rpm over peak horsepower
expected.
#13. What
type of ECM: Speed Density 1990, 91, and 92. ECM
#'s 1227730, 16196344, 16198262, 1227277,
16197128, 16198260, or Mass Air
1986, 87, 88, and 89. ECM #'s 1227165, 16198259,
and 16198445.
Caution
to those against using to large of a
fuel injector. A 24 lb. 3 bar (43.5 psi.) injector
can easily handle upwards of 400 hp by turning up
the fuel pressure to 50 psi. High impedance
injectors require at least a 2 millisecond pulse
width at idle. If you run to large injector you
will sacrifice your idle quality. The single
greatest misnomer about TPI is injector sizing.
1989 thru 1992 used the same size injector for
both 305's and 350's at 20.7 lbs. @ 3 bar (43.5
psi). 305's used regulators set at 41 lbs. while
350's used 48 lbs. The manufactures have learned
that higher pressures are better. Today's LS1's
are running 3.7 bar (55 psi). This gives a better
spray pattern to optimize the use of fuel. 350's
should run 21 lb. injectors with the pressure
turned up based on modifications. 383 to 406's
should use 24, and so on.
Vehicle
Speed Sensor (VSS) is highly recommended. EGR will
not function, and torque converter won't lockup
without VSS being hooked up. Programming is
optimized to know whether the vehicle is moving or
not. You will not be smog legal without it,
and the motor may die in certain deceleration
situations.
I
have
been asked to adjust speedometers for different
gear ratios and tire heights. Although GM did
create numerous broadcast codes for TPI and
referred to them by gear ratios. The Memcal nor
ECM controls the speedometer. The 4 pulse sine
wave (4000 pulse per mile) is received by the ECM.
It then sends out a signal to a DRAC module
(Digital Ration Adapter Controller) which performs
the correct calibration for the speedometer. GM
only used two basic fuel tables for speed density,
but used numerous spark tables. It’s my
experience that these spark tables are not
correlated with gear ratios, but rather chosen
based on expected performance of the model for
which the broadcast code was designed. Some models
may have replaceable gears at the VSS that can be
changed. These years did not use the DRAC module.
The smog
pump, or Air Injection Reactor (AIR), and the
Charcoal Canister Purge (CCP) will not set a code
in TPI and does need to be programmed out.
However, it can shut it off if it bothers you to
see it on your diagnostic equipment.
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