DIY Performance Tuning

Daytona Twin Tec TCFI III Gives You Complete EFI Control

1. The TCFI III-Kit components include the TCFI III module, the WEGO IIID module, the USB Interface, two Bosch LSU 4.2 Wide-Band Sensors, all the necessary cables and hardware, a CD with software and documentation, and a full set of printed instructions (not pictured).

2. To begin we removed the seat, disconnected the negative battery terminal, and removed the side covers. Next we removed the two OE O2 sensors and secured the OE mating connectors out of the way. An O2 sensor socket is nearly essential to remove these with the exhaust on the bike. It's usually too tight to get a wrench on the rear sensor, and a regular socket will not go over the pigtail wires. Note that if your bike doesn't have OE sensors, then you'll have to weld the included bungs to your pipes.

3. Next we removed the OE ECM. It's held by two 1/4-20 hex head bolts screwed into brass inserts pressed into a plastic bracket. These bolts have threadlocker and are difficult to break loose. We rocked the bolts to no avail. The brass inserts spun in the plastic and the bolts didn't back out.

4. To make it easier to work on, we unbolted the entire plastic bracket, unpluged the ECM, and disconnected the small fuse holder and extra plugs.

5. We carefully drilled out the two bolts using progressively larger drill bit sizes. The bolts finally came out. We tapped the brass inserts and used new bolts to install the TCFI III module. An alternate method would be to drill a 1/8-inch hole perpendicular to the bolt into the side of the plastic and into the brass insert, then insert the drill bit shaft into the hole to prevent the insert from spinning, or replace the plastic bracket.

6. Next, we installed three wires into the ECM (or now the TCFI) 36-pin Delphi connector. To open the connector, use a small screwdriver to press the recessed tabs on each end of the clear plastic cap. Then release the three small tabs on the body.

7. The first wire we installed was the green PC Link jumper wire. It has a small female Delphi Micro-Pack terminal on one end and a male Deutsch terminal on the other end. The female terminal went into position 9 of the Delphi connector. Then we pulled the blue plug from position 9 and pushed the terminal through until it locked into place and was even with the other wires.

8. To install the male terminal of the green wire into position 1 of the OE diagnostic connector (a four pin Deutsch), we removed the green retainer from the connector.

9. Then we pulled the orange wire plug out while using a small screwdriver to gently release the plastic wire tabs inside the connector. We pushed the male terminal through position 1 and inserted the plug and each wire until they clicked onto their tabs. Then we inserted the green retainer.

10. Next, we installed the white and blue WEGO extension wires, each with a small female Delphi Micro-Pack terminal on one end and a Packard Weather connector on the other end. The white wire went into position 8 and the blue wire into position 23. On models with OE O2 sensors, first remove the wires from those positions, then label and tape them. Close the Delphi connector and tie-wrap the end.

11. We then attached the WEGO unit near the TCFI using hook and loop strips. Here's everything on the right side installed.

12. We connected the two Bosch sensors to the 6 pin mating connectors on the WEGO wire harness. The longer cable (with the yellow band) is for sensor 1 (front). We ran the cables along the chassis following the OE sensor cables. Do not install the sensors in the exhaust. Here you can see the rear sensor in the background waiting for the free air calibration procedure.

13. The WEGO module needs a switched +12 volt power source, so we routed the red WEGO wire to the left side of the bike and attached it to the accessory fuse in the fusebox. We used the supplied brass fuse tap and 3/16-inch female crimp terminal. Additionally, we connected the two black WEGO wires to an existing frame ground using the supplied ring terminal.

14. To perform the free air calibration procedure, we reconnected the negative battery terminal, turned the free air trimpots on the WEGO unit full counterclockwise, turned on the power with the Ignition/Headlamp switch, and waited 60 seconds for the system to stabilize. Next, we slowly rotated the trimpots clockwise until the corresponding LED began to flash at a rapid rate. Then we turned off the power and installed both O2 sensors.

15. With everything installed, we were ready to hook up the PC and perform the initial TCFI setup. We connected the USB Interface cables to the PC and the OE diagnostic port, started the PC Link TFCI III software, opened our initial setup file (the 2007 96CID file), edited the basic parameters per the instructions, turned on the Ignition/Headlamp and Off/Run switches, and uploaded the setup file to the TCFI module.

16. While everything was still connected, we performed the Throttle Position Sensor (TPS) check and adjustment. We started the TCFI III Log software and used the View Idle TPS command to see if the TPS value is between 0.30-0.80 volts. Optimum is 0.40 volts. Ours was a little high, out of the green band, so we had to adjust the TPS.

17. We detached the air cleaner cover, air cleaner, and backing plate. We used a #20 torx bit to remove the TPS. The inner screw is very close to the rear cylinder cooling fins, so to remove it, we cut off most of a #20 torx bit and used it with a 1/4 wrench to extract the screw.

18. Since the Factory doesn't adjust this part, we had to elongate the mounting holes to allow for movement. We taped over the exposed inner portions of the sensor and used our soft jaws to hold it in our vise. With a spiral cutting bit and a Dremel tool, we shaved about 1/32-inch off the sides of each hole. That gave us room to put the TPS value right on 0.40 volts.

19. Before performing the Idle Tuning procedure, we turned everything off for at least five seconds to let the system recycle and reset itself. With the PC connected to the bike, we started the TCFI III Log software, and turned on both the Ignition/Headlamp and Off/Run switches, and started the motorcycle. We used the View Real Time Data command to monitor front and rear cylinder AFR (air/fuel ratio) and BLM (block learn multiplier), ET (engine cylinder head temperature in degrees Celsius), and Intake Air Temperature (IAC) values. The most important thing at this point is that as the engine warms the IAC drops near a nominal value of 30. If it doesn't, then the idle stop screw needs adjustment. That screw requires as special T15 Tamper-Proof Torx Plus Bit Socket with a 5-lode design. Fortunately, our IAC was fine and other values were within spec, so we made no adjustments.

20. Now we were finally getting to some fun stuff-we were ready to auto-tune the TCFI. As we described in the text, this involves five sessions of riding the bike, downloading data from the TCFI, editing the data, and uploading the edited data back to the TCFI. Here's what the rear BLM table looked like after our first run. The red cells indicate positions where the system has run out of correction range. By using the Apply BLM Table command, the software automatically corrects the fuel tables. Follow the instructions to tune all parameters.

21. One neat trick the TCFI did was log motorcycle operation data for the last 60 minutes. We saved the logs after each tuning run and browsed them. Here's a log view showing engine RPM and front BLM values. The TCFI stores data for sixteen parameters. These logs allow us to precisely locate events, such as pinging, and make any necessary corrections.

22. The final cool feature of the TCFI was the ability to view real time data as the engine was running, as we did for idle tuning. This is the ultimate dashboard and instrument cluster. Not that we recommend anyone riding with a PC perched on their handlebars! For that, Daytona offers software and cable for a Palm PDA to view any three parameters while riding. But being able to view real time data in the shop or on the dyno, all of which is being logged, then use that to performance tune the bike-well, that's taking control to the next level.

Want complete control of your Twin-Cam engine management so that you can easily re-tune each time you make a performance upgrade without a visit to a dealer or a dyno shop? Then the Daytona Twin Tec TCFI III Fuel Injection Kit (TCFI III-KIT MSRP $875.00) is an upgrade option you may want to consider, available for '01-'06 Twin Cams with 36-pin Delphi systems.

This kit is serious business that delivers serious benefits. It consists of two main components. The first is the third generation TCFI III (Twin Cam Fuel Injection) module, which is a fully programmable plug-in replacement for the stock 36 pin Delphi ECM (Engine Control Module). The TCFI solves tuning problems with highly modified engines using the same technology as high-end automotive racing. The TCFI also has built-in data logging that stores the last 60 minutes of operation data at 10 samples/second.

The second component is the new WEGO IIID (Wide-band Exhaust Gas Oxygen) interface, which allows auto-tuning of EFI parameters during actual on-road riding conditions. The kit uses a Bosch LSU 4.2 wide-band sensor for both front and rear cylinders. The user programs a table with the desired air/fuel ratios, and the system does the rest. Unfortunately, it doesn't auto-tune timing. But, hey, "auto-tuning," how cool is that? Let's see.

However, before we do, we must consider a big issue. The first sheet in the instruction package is a bright yellow piece of paper with the warning "Read before opening any boxes." Presumably that's to facilitate returning those boxes if the owner gets cold feet after reading the remaining cautions. Foremost of those is, "If you have never worked with H-D EFI systems, the TCFI is not the place to start." The necessary skills and resources you'll need are PC literacy, basic engine tuning concepts, mechanical ability, and time. A service manual for your model would be handy, too. The bottom-line caution is that before you continue you need to make a realistic assessment of your skill level and commitment.

Having done that, we plunged ahead with our untrained-but reasonably competent-garage-mechanic/writer installing the kit on his stock '07 Road King Custom. While the TCFI kit sounds intimidating and complex, it is also well-designed, documented, and straightforward. We took our time and worked through each step in the process. Plus, we tapped into the Daytona tech support and the readily available and enthusiastic help from Harley-Davidson Forum members, notably John Pike (SpikeCT).

Setup began in the office where we installed the two major software components and the USB Interface on a laptop PC. The PC Link TCFI III software is the primary programming and tuning tool because it allows the user to upload custom ignition and fuel tables and other engine parameters to the TCFI III. The TCFI III Log software allows the user to view real-time engine data, download and display stored operation data, and to control certain engine functions. The USB Interface provides communications between the TCFI III module and the PC software.

Installation of the hardware components on our '07 H-D Road King Custom was not difficult. However, it was tedious because the Motor Company doesn't expect the owner to replace critical electronic parts, therefore the removal of those parts often included a couple of gotchas, which required moderate shop skills to work around. We noted those as we encountered them.

After everything was installed on the Road King, the TCFI required an initial setup before starting the engine for the first time. This setup establishes the base TCFI parameters such as engine horsepower, injector size, and the appropriate ignition and fuel tables. Daytona Twin Tec provides several setup files for typical engine applications to use as starter sets. For our bike we used the '07 96CID file. Once the initial setup file was uploaded, the TCFI was ready for idle tuning and performance auto-tuning.

Idle tuning uses the PC software to check the TPS (Throttle Position Sensor) and to verify that basic engine variables are within nominal ranges while the engine idles. Adjustments at this stage are critical to insure that the engine is within sound operational limits before riding and auto-tuning.

Auto-tuning is a closed-loop cyclic process of riding the motorcycle at varying loads and speeds, each time downloading the current setup data from the TCFI, editing and applying the tables for improved operation, uploading the data back to the TCFI, then repeating. Typically five runs are sufficient for tuning.

Here we've covered the basic installation of the TCFI III kit and tuning for a stock motorcycle. During our first couple of auto-tune runs we did encounter some hesitation and pinging. However, after the final run, the stock Road King performed as well as or better than before. We didn't spend much time tweaking the TCFI III for the stock configuration because we'll soon upgrade the air and exhaust. We'd rather devote our time to maxing out those.

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