STG Ultimate Chip Installation Instructions
Install 3 bar MAP sensor (not included) either in place of or near original 2 bar. The stock MAP sensor looks similar to a black soap bar and is located on the drivers side of the engine compartment mounted vertically on a bracket next to the intake manifold.. Remove the vacuum line and electrical connector from the sensor, and gently pull it from the bracket. It will snap out, there is not connector holding it in place. For specifics of the stock 2 bar sensor refer to the Syclone or Typhoon shop manual. Part number for the 3 bar map sensor is 1604-0749 (GM/AC Delco sensor assembly, stock usage was 1989 Turbo Trans Am). The 3 bar sensor is a necessary component, and can be found for $45 - $90. There have been mishaps of people receiving 2 bar map sensors instead of 3 bar sensors. An easy way to check if you have the correct sensor is to observe the stock boost gauge in your dash, as its readings will be incorrect with the 3 bar sensor. The stock boost gauge will not cross from green to yellow at 0 psi, you’ll now remain in the green section when crossing into boost (reading as vacuum). Finally, the 3 bar programs are tuned for a static (no vacuum) fuel pressure of ~50 psi at idle.
Installation of hardware. Remove stock memcal (chip) from ECM. ECM is located behind the glovebox, accessible by removing the plastic panel under the passenger side dash, and passenger side kick- panel. First, the blue cover of the MEMCAL (stock chip) needs to be removed for it to fit properly into the ecm. This can easily be done with a small screwdriver, by prying up the clips that hold the cover on. See photo next page. Notice the orientation of the MEMCAL in the picture below in relation to the carrier. The MEMCAL’s EPROM (black 32 pin IC chip) will be next to the EPROM on the carrier. Once the MEMCAL is attached to the new carrier, you will slide the MEMCAL under the lip of the ECM and then push the carrier into the connector in the ECM as shown in picture. Note that this picture also shows a ZIF socket that is an option for those who have purchases just the hardware and want to program their own chip. Most Ultimate owners will not have this socket so pay no attention to the last 2 frames on the right showing the EPROM being inserted into the ZIF socket.
Plug the carrier into the connector in the ECM from where you removed the MEMCAL. If you have the carrier in properly, the two retaining clips will close as you push the carrier into the connector. The gauge style displays will be shipped without the cable attached to either the carrier or display. The “radar” style, which is enclosed in a 3”x3” black enclosure, will come fully assembled. For gauge style owners only: once the display is installed into its 2 1/6” pod (gauge holder) you can attach the cable to both the carrier and display. Connect the cable to the carrier such that the cable points towards the center of the circuit board, not away from it. The correct end of this cable has the exposed shielding nearby. Once connected, put the cover back on the ECM and replace screws. The exposed shield on the cable (gauge style only) will be “crimped” between the cover an ECM shell. This is for grounding purposes of the shield. On the display end, insert the connector into the back of the gauge, with the cable pointing downward or away from the center of the gauge.
At this point, you can turn the ignition key on, with engine off. Make sure the check engine light stays on steady, which is normal. If you have a scan tool, you can read the PROM identification’s (Prom id’s) by toggling the switch through the positions. Every setting will have its own PROM id. These steps will verify that all is working properly. You can start the truck at this point and the check engine light should go off and the truck should run normally. You can try the security position if you have this option and the truck will not run. The valet program will not run the intercooler pump, which you can also verify if you wish. This program also has the timing advance reduced significantly and a 4000 rpm limit, making it a part throttle only program. Programs can be changed while truck is running or shut down.
Once you’re satisfied that all is correct, shut down the vehicle and run the ribbon cable/switch to wherever you want to locate it. Re-install the ECM up behind the dash. The “radar” style display can be located in many places, on the “tray” below the ashtray, or in the glovebox have been a couple popular choices. If you wish to locate it in the glovebox, there is a small access panel in the back that can be removed, allowing the display cable to be run inside. You will have to remove the cable from the display first, by simply removing the display cover and pulling the cable out of the connector. After running the cable into the glovebox, reconnect the cable into the display unit and replace the cover. Make a note of the connector orientation before pulling it off so that it can be reinserted the same way.
Operation: Once installed, operation is very straightforward. On the “radar” style displays, the left button will toggle forward (up) through the settings, from lowest boost/timing to highest. The right button will toggle down. On the gauge style, the opposite is true, right is forward (up), left is reverse (down). The display will indicate the current level of timing and boost, or any special settings contained in the chip, such as security (SEC) or valet (VAL). The timing is indicated by the first two digits, as T1, T2, or T3. The larger the number, the more advance in the program. T1 is a level similar to that of the stock calibration, and will be safe to use with premium fuel at boost levels up to 17-18 psi on a stock vehicle. T2 has a couple more degrees of advance, throughout the rpm range and will require more than 93 octane at the 18 psi and higher boost levels. The T2-16 and T2-17 should be ok to use with 93 octane or better. This is up to the user to determine by monitoring knock, as it will vary from vehicle to vehicle. T3 has a couple more degrees advance than T2 and will require additional octane to run safely.
The boost level is indicated by the second 2 digits of the display, as the value in PSI (16, 17, 18, etc.) Note that the 24 psi programs will drop approximately 1 psi at WOT above 4800 rpms, to 23 psi. For those with stock turbos, keep in mind the limits of this turbo. The boost levels above 20 psi might not be reached due to the small flow characteristics of the stock unit. Also, due to its inefficiency above 20 psi, horsepower gains will probably be minimal above this level even if you are able to attain them.
The unit can be “locked” or “unlocked” by entering a code by pressing the buttons in a certain order. This disables/enables the pushbutton switches until the sequence is again entered. To do this simply push both buttons at the same time. Four “X”s will appear, indicating that the request is recognized. Then the word “open” or “lock” will appear, depending in the current state. Then the word “KEY?” will appear at which time hit the “up” button twice, and the “down” button once. Each time one is pressed, the word “KEY?” will momentarily disappear, indicating that it had recognized the code being entered. After entering the code, there will be a 3 second pause, then the word “LOCK” or “OPEN” will appear, depending on its new state. A moment later the current program setting, T1-15, T1-16, etc. will reappear.
This may sound complicated at first, but once it’s done successfully it is simple to execute.
Programs can be selected or switched at any time the vehicle ignition is on. The display/switching unit requires power to operate and will not change programs without being powered up.
The best method of setting the security (SEC) program is to shut the vehicle off in whatever mode you were using, then turn the ignition on with engine off and toggle to the SEC program. Use the method described above to “lock” the unit, and turn the ignition off. The vehicle will not start now and the settings cannot be changed. To run the vehicle again, turn ignition on/engine off, unlock the unit as described above and toggle to desired program. Vehicle will start in a normal manner at this point. Many users have found that they can simply toggle to SEC to shut the motor off, then lock the unit. This effectively does the same thing as turning off the ignition key, which is shutting down the ignition/fuel system and saves them a step in the process.
The Valet (VAL) program is a part throttle only program. It has an rpm limit of 4000, no intercooler pump operation, and significantly reduced timing. If an attempt is made to run at WOT (wide open throttle) the truck will sluggishly accelerate to 4000 rpms, then hit the rpm limit, shutting off the injectors. The truck will behave normally during all other operating conditions.
Programs for the stock injector chips are accessed sequentially in this order: SEC, VAL, T1-15, T1-16, T1-17, T1-18, T1-20, T1-22, T2-16, T2-17, T2-18, T2-20, T2-22, T3-20, T3-22, and T3-24.
