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.
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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).
1. The TCFI III-Kit components include the TCFI III module, the WEGO IIID module, the USB
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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.
2. To begin we removed the seat, disconnected the negative battery terminal, and removed
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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.
3. Next we removed the OE ECM. It's held by two 1/4-20 hex head bolts screwed into brass
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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.
4. To make it easier to work on, we unbolted the entire plastic bracket, unpluged the ECM
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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.
5. We carefully drilled out the two bolts using progressively larger drill bit sizes. The
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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.
6. Next, we installed three wires into the ECM (or now the TCFI) 36-pin Delphi connector.
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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.
7. The first wire we installed was the green PC Link jumper wire. It has a small female D
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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.
8. To install the male terminal of the green wire into position 1 of the OE diagnostic co
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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.
9. Then we pulled the orange wire plug out while using a small screwdriver to gently rele