TPI programming service for your stock or custom Street Rod

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 Charcoal Canister Purge (CCP): Enable / Disable.

#11 Air injector Reactor (Smog Pump): Enable / Disable.

#12. Cooling fan(s) settings. What degree thermostat?: 160, 180, or 195. I recommend using at least a 180 thermostat for TPI.

#13 Knock sensor: High compression, and high lift cams can create chatter that will be picked up by the sensor. Knock sensor may need to be disabled in certain combinations.

#14. Speed limiter: Default is 255 mph / or specify desired speed.

#15. RPM limiter: Default is 10,000 RPM / I recommend limiting it to 800 rpm over peak horsepower expected.

#16. 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.

#17. Cold start injector may be eliminated at your request for those vehicles that used them.

#18 Do you have Longtube Headers or Shorties?

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. GM used many different sized injectors, and at different pressures during the TPI years. It is critical that we get the flow rate set correctly for any combination. 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, but some very high flow combinations can run 30's.

Vehicle Speed Sensor (VSS) is highly recommended. EGR will not function, and torque converter won't lockup without VSS being hooked up unless a 3rd party device is used. 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. Mass Air systems used a 2 pulse square wave (DC), but speed density used a 4 pulse sine wave (AC). You may use any sine wave sensor with speed density, and the output signal may be modified in the programming. IE: A later model T56 with a 17 pulse sine wave can be used, and the input signal modified in the programming. All 700R4's from 1984 to 1992 used a 4 pulse sine wave output. However, in the mass air cars this was converted to a 2 pulse square wave and sent to the ecm. If you have a speed density conversion you may use the signal from the earlier transmission. If you use a 4L60E or 4L80E I'll need your tire size and axle ratio to assign the proper value in the programming.

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, so the gears in the transmission must be changed. The 4 pulse sine wave (4000 pulse per mile) is received by the ECM in speed density cars, and then outputs to the speedometer, and cruise control. Mass air cars work as stated above. GM only used two basic fuel tables for speed density 350's, but used numerous spark tables. Itís 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. All 700R4's have replaceable gears at the VSS that can be changed. These years did not use the DRAC module like TBI.

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. 

Copyright © 2019 Scott Hansen