Twin Tec TCFI Gen II Fuel Injection System Tuning Manual
The TCFI Gen II is a fuel injection system designed for highly modified Harley-Davidson motorcycles with fuel injected Twin Cam 88 engines. It is specifically designed for engines with long duration/high overlap camshafts. The TCFI can be used to tune the engine parameters such as AFR (air/fuel ratio), RPM, and TPS (throttle position sensor). This manual provides detailed instructions on installation, setup, and tuning the TCFI Gen II system.
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Twin Tec
TCFI Gen II Fuel Injection
System Tuning Manual
OVERVIEW
The Twin Tec TCFI Gen II fuel injection controller replaces the original equipment (OE) Delphi
® controller on 2001-2005 Harley-Davidson
®
motorcycles with fuel injected Twin Cam 88
®
engines. The TCFI solves tuning problems with highly modified engines with long duration/high overlap camshafts. The TCFI is not intended for street operation with stock or mildly modified engines.
The only practical means of tuning any fuel injection system is with an exhaust gas analyzer.
Tuning the TCFI requires the wide-band exhaust gas oxygen (WEGO) sensor interface. and diagnostics. You can view any three of the engine parameters that are logged by the TCFI system. Check our website at www.daytona-twintec.com
for more information about TCFI II View, including PDA and cable requirements.
CAUTION: Tuning the TCFI requires competency in PC operation, using
Microsoft Windows based programs, and basic engine tuning and fuel injection mapping concepts including the use of an exhaust gas analyzer to monitor AFR (air/fuel ratio). The TCFI installer is assumed to be familiar with the Delphi
fuel injection system and to have access to basic test equipment and factory service manuals.
TUNING REQUIREMENTS
You must be able to monitor engine parameters including AFR and RPM during the
tuning process. While you can use TCFI Log software and a laptop PC for this purpose, situations may arise where a mobile display system is required.
TCFI II View software allows using a Palm OS based handheld organizer (PDA) to view engine parameters on motorcycles equipped with the Twin
Tec TCFI fuel injection controller. This facilitates tuning
SYSTEM INSTALLATION
1. Check for updates. Before proceeding, check our website at www.daytona-twintec.com
for available upgrades for the TCFI firmware and accompanying
PC based software. Carefully read the instructions and familiarize yourself with operation of both the
PC Link TCFI software used for tuning and the
TCFI Log software used for data logging and analysis.
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2. TCFI Controller. Carefully read the TCFI instructions and install the TCFI unit
2. Start the PC Link TCFI software and open the appropriate setup file.
3. WEGO wide-band exhaust gas oxygen sensor
interface. Carefully read the WEGO instructions and install the WEGO unit.
4. Initial setup and tuning. Follow the instructions in this tuning guide. Do not start the engine until initial setup has been completed.
3. Check module parameters and make any required changes such as estimated horsepower or injector flow rating. You must also set the VSS frequency for your model. This affects speedometer scaling.
Refer to page 12 of the PC Link TCFI instructions.
4. Turn the ignition key and run/stop switch on.
5. Upload the setup data to the TCFI unit.
EDITING OPERATIONS
After initial setup, the TCFI tuning process requires multiple edits of the engine tables and parameters using PC Link TCFI software. Unless otherwise noted, editing involves downloading the current setup data in the TCFI, performing the required edits, and then uploading the edited setup data. At the same time, you should always print out any affected tables and parameters and save the file with a unique filename. Keep detailed written notes on the changes you make and the associated filename.
6. Cycle the run/stop switch. This initializes the idle air control motor.
7. Follow the instructions for tuning the system, from the throttle body adjustment described below through the final checks listed on page 5.
8. If you have questions or encounter problems, please call our tech support.
THROTTLE BODY ADJUSTMENT
New customers with limited PC experience often become confused and make mistakes such as not saving table edits to buffer memory before uploading.
We suggest that you spend some time practicing with the software, including the Copy, Paste, and Modify commands on the right mouse button pop up menu.
INITIAL SETUP
The TCFI requires setup, using PC Link TCFI software, before running the engine for the first time.
Setup establishes module parameters such as engine displacement and injector size and appropriate ignition and fuel control tables. You should carefully read this entire instruction manual before proceeding.
An alpha-N (throttle position and RPM based) fuel control system such as the TCFI requires that certain condition be met by the throttle body. All aftermarket throttle bodies and even some stock Delphi units will require adjustment for proper operation.
Idle control is by means of the idle air control
(IAC) system. The throttle blade(s) must remain at a fixed position against the idle stop screw when the throttle is closed. The throttle body is affected by thermal expansion. If the idle stop setting allows the throttle blade(s) to completely close and contact the throttle bore, the blade(s) may bind while cold. If the idle stop setting forces the throttle blade(s) to stay open too far, the IAC system can lose control and set a diagnostic code. Either case can result in starting and idle stability problems.
Setup data files are provided in the program folder for typical 88 CID and 95 CID engine applications (TCFI_Setup88.dat and
TCFI_Setup95.dat). Refer to page 6 for additional setup files for dual independent runner throttle
bodies. The 88 CID engine is assumed to have stock compression, mild performance camshafts, low restriction air cleaner and low restriction slip-on type exhaust. The 95 CID engine is assumed to have approximately 10:1 compression, high flow heads, high performance camshafts, low restriction air cleaner, aftermarket type throttle body (50mm or greater), and low restriction slip-on type exhaust. Setup guidelines for larger displacement engines are given on page 6.
Setup your TCFI unit as follows:
1. Connect the PC link cable between the TCFI unit and your PC.
Issues with throttle blade, linkage or cable binding are often encountered with installation of an aftermarket throttle body. Verify that the throttle system operates smoothly, that the take up cable has some slack, and that the return cable forces the throttle blade(s) against the idle stop. Verify that the throttle blade(s) do not bind when cold or hot.
As an initial adjustment on a cold engine, set the idle stop screw so that the throttle blade(s) just barely open and do not bind. Then perform the idle TPS adjustment described in the next section. Use TCFI
Log or TCFI View software to verify that the IAC position stays in the range of 30-40 (35 nominal) steps when the engine is fully warmed up and running at a stable idle condition. If the IAC position is outside this range, make an adjustment to the idle stop screw.
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Please note that if you make any adjustment to the idle stop screw, you must also recheck (and probably readjust) the idle TPS setting as explained in the following section. require manual tuning of idle fuel values and adjustment of the idle stop screw. This can be done in one session and should be completed before the motorcycle is driven on the road.
You can adjust the idle stop when the engine is running while observing real time data with TCFI Log.
Make sure the engine temperature stays in the normal operating range of 110-130
° C. If you run the engine for more than a few minutes, you should use a shop fan directed at the engine to provide cooling air. As noted above, idle stop adjustments affect the TPS sensor. If you make an idle stop adjustment that increases the TPS value above 1%, the TCFI will no longer recognize an idle condition. You must stop the engine and perform an idle TPS adjustment before proceeding.
IDLE TPS ADJUSTMENT
Proper operation of the TCFI system depends on an accurate throttle position sensor (TPS) signal.
You can use TCFI Log or TCFI View software to check the TPS sensor. Carefully read the software instructions before proceeding.
Please note that during the warm up period after initial engine start, fuel control is open loop (no feedback from the WEGO sensor) and relies entirely on correct values in the Alpha-N table. The TCFI will enter closed loop AFR control mode after the engine warm up time (180 seconds) has elapsed and the engine has reached the warm engine temperature (96°
C). Under cold weather conditions, a considerable amount of time may be required for an air-cooled engine to reach normal operating temperature. If the motorcycle will be operated under cold weather conditions, you can reduce the warm engine temperature setting (under Module Parameters) to
75° C.
CAUTION: Failure to perform the required idle stop and TPS adjustments is the leading cause of installation problems requiring tech support.
Start the engine and allow it to idle until it reaches normal operating temperature. Monitor engine data with TCFI Log or TCFI View software. The average AFR value should remain in the 12.5-13.0 range near the end of the warm up period just before the cold engine status display disappears (indicating closed loop). Use the PC Link TCFI software and make small adjustments to the idle cells in the Alpha-N fuel table (cells for 750, 1000, and 1250 RPM at 0% throttle position). If the AFR value is too high (lean), add 1.0 to
1.5 to the idle cells. Always change each of the three idle cells by the same amount.
Connect the PC Link cable and start TCFI Log or TCFI View software. Turn the run/stop switch on but do not start the engine. For TCFI Log, use the View
Idle TPS command on the View menu. Idle TPS volts are displayed on the TPS bar graph gauge. For TCFI
View, select TPS volts display. With the throttle closed, the TPS value must be in the .35-.45 volts range.
To avoid having to perform multiple cold start tests for idle tuning, you can use the following procedure. Use TCFI Log or TCFI View to examine the block learn multiplier (BLM) value when the engine has reached normal operating temperature (110-130 ° C) and is running in a stable idle condition. The BLM value should be between 90-95%. If the BLM value is higher, slightly increase the idle cells in the Alpha-N table.
Some aftermarket throttle bodies are supplied with undercut screws that facilitate TPS sensor adjustment. If you need to make an adjustment and you do not have the undercut screws, you will have to carefully drill out or press out the brass bushings on the TPS sensor and then use #8 flat washers with the original screws.
Do not attempt to substitute the older style
Marelli TPS sensor. While the older style TPS sensor has screw slots that provide easy adjustment, it has a different output characteristic.
In general, BLM values below 100% indicate that the TCFI is removing fuel in closed loop to correct a rich condition. BLM values above 100% indicate that the TCFI is adding fuel in closed loop to correct a lean condition. A BLM value of 90-95% at idle indicates that the open loop values in the Alpha-N table are slightly rich and that the TCFI is removing a small amount of fuel to make the necessary correction. This slightly rich open loop condition is desirable as a safety margin during cold start and hot restart before the TCFI enters closed loop.
IDLE TUNING
Once the initial setup has been completed, the
TCFI unit is ready for operation. Most applications will
Hot engine restart, after a 5-10 minute hot soak period, is usually the most critical phase as far as idle
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AFR. After the engine has been run for some time and oil temperature is at least 85° C (185° F), shut the engine off for 5-10 minutes. Restart the engine and allow it to idle. Verify that the average AFR does not exceed 13.5 during the first three minutes of operation.
You may need to make further adjustments to the idle cells in the Alpha-N table to meet this requirement.
As a final step, use TCFI Log or TCFI View software to verify that the IAC position stays in the range of 30-40 (35 nominal) steps when the engine is at normal operating temperature (110-130° C) and running at a stable idle condition. If the IAC position is outside this range, make an adjustment to the idle stop screw. Use a shop fan directed at the engine to maintain the operating temperature during the adjustment procedure. Please note that if you make any adjustment to the idle stop screw, you must also recheck (and probably re-adjust) the idle TPS setting.
AUTO-TUNING
Auto-tuning is done with the WEGO sensor installed on the rear cylinder. The closed loop autotuning process consists of operating the motorcycle through a wide range of loads and speeds while periodically monitoring progress using the PC Link
TCFI software. Long rides at constant speed and load are of no value. The best technique is to very slowly accelerate through the useable RPM range in every gear, allowing several seconds of operation in each
RPM and throttle position based cell. Also operate the motorcycle at various fixed speeds likely to be encountered during normal riding. For safety reasons, wide open throttle runs should be done on a closed course. For reasons discussed on page 7, we do not recommend auto-tuning on a dyno.
Use TCFI View to monitor AFR. If AFR values appear very lean (above 14.5), we suggest that you edit the Alpha-N table to add 15-20% fuel to all cells except idle cells before proceeding. You can use the
Modify command (i.e. select a range of cells and enter
+15%). Auto-tuning works best if you start with a slightly rich Alpha-N table.
After 1-2 hours of engine operation, use the PC
Link TCFI software to examine the block learn multiplier (BLM) table. Cells that are shaded red indicate that the system has run out of correction range. If you see red cells on the BLM table, you can use the Apply BLM to Alpha-N Table command to automatically correct the Alpha-N fuel table. This is further explained in the Editing 3D Table Data – BLM
Table section of the PC Link TCFI instructions.
Auto-tuning is a statistical process. The longer the operating time, the greater the probability that more
Alpha-N cells will be covered. However, even a varied operating cycle can miss some cells. After you use the
Apply BLM to Alpha-N Table command, take some time to examine the modified Alpha-N table. Unless your engine has some unusual camshaft and exhaust interactions, the table should appear smooth (with gently rising slopes). If you spot sharp peaks or deep valleys, these cells have probably been missed during auto-tuning and will require some manual edits to smooth them into the surrounding terrain.
The Alpha-N table represents percent injector pulse width (fuel flow) before correction for BLM, front cylinder trim, barometric pressure, intake temperature, and cold start enrichment. You can use the following guidelines to smooth the Alpha-N table:
1. At part throttle (low TPS%), Alpha-N values in each row will tend to decrease as RPM increases
(because the throttle is choking air flow).
2. At wide open throttle, Alpha-N values in each row will tend to follow the engine torque curve.
3. In any given RPM column, Alpha-N values must always increase with TPS.
Continue to operate the motorcycle under varying conditions for another 1-2 hours, re-examine the BLM table, and repeat the Apply BLM to Alpha-N
Table command as described above.
Repeat this process until most of the BLM cells remain in the 90-110% range.
During this auto-tuning process, you may encounter two potential problems: spark knock or an excessively lean front cylinder AFR causing popping back through the air cleaner and lean surge.
If spark knock is noted under wide open throttle or throttle roll-on, use PC Link TCFI software to edit the ignition advance table and reduce the ignition advance
3-5 degrees under the conditions that cause spark knock. Using the TCFI Log software to examine engine data may be very helpful for determining exactly what manifold pressure and RPM values were encountered.
An excessively lean AFR in the front cylinder may be due to fuel robbing caused by air flow reversion during the overlap period when both the exhaust and intake valve are open. If popping back through the air cleaner and lean surge is noted while the observed AFR is less than 14.5 for the rear cylinder, the front cylinder trim table values will require adjustment. The fuel robbing effect is usually most pronounced at 5-15% throttle position between 1750-
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2500 RPM. Try increasing these cells in the front cylinder trim table by 10-30%. Then continue with the auto-tuning process as explained above.
FRONT CYLINDER TRIM
After the auto-tuning process has been completed with the WEGO sensor installed on the rear cylinder, you should perform the front cylinder trim procedure as described below. the front cylinder AFR. If the values appear to stay within about ±0.5 AFR of the AFR command most of the time, the front cylinder is trimmed correctly. If not, repeat steps 3 and 4.
6. Return the WEGO sensor to the rear cylinder. Run
PC Link TCFI software. Download your current setup data. Edit module parameters to re-enable closed loop AFR mode. Upload the modified setup data. This re-establishes normal closed loop operation of the TCFI unit.
WARNING: All engines with siamesed runner throttle bodies (such as the stock Delphi
®
) or 2-into-1 exhaust systems (including any stock systems with crossover) will require front cylinder trim. Failure to perform front cylinder trim may result in lean operation and possible engine damage.
1. Transfer the WEGO sensor to the front cylinder.
You can order an additional weld nut for the front cylinder and a plug for the rear cylinder direct from the WEGO page on our website.
FINAL CHECKS
volts. On cold start, verify that the average AFR value stays in the 12.5-13.0 range near the end of the warm up period. Verify that the IAC position is in the range of 30-40 (35 nominal) steps and the
BLM value is 90-95% when the engine is at normal operating temperature (110-130° C) and running at a stable idle condition. On hot restart after 5-10 minute hot soak, verify that the average idle AFR does not exceed 13.5 during the first three minutes of operation.
2. Auto-tuning. The auto-tuning process is considered complete when most BLM table cells remain in the 90–110% range.
2. Run PC Link TCFI software. Download your current setup data. Edit module parameters to disable closed loop AFR mode. The TCFI will now operate in open loop and allow you to log AFR data for the front cylinder without affecting any tuning that has already been done for the rear cylinder. Set the data logging interval to 0.3 seconds (gives best results). With this setting, the
TCFI will log the last 8 minutes of data.
3. Operate the motorcycle under varying conditions.
Use the TCFI Log software and collect data for at least 5 test runs. Each test run need not be longer than 10-12 minutes (several minutes for the engine operating conditions to stabilize plus 8 minutes of data logging capacity). Save the data for each test run to disk using unique filenames (keep notes).
This data will contain front cylinder AFR values used by the Auto-Tune function.
4. Use the PC Link TCFI software, download your current setup data, and run the Auto-Tune Front
Cylinder Trim Table command as explained in the
PC Link TCFI software instructions (pay attention to the note about idle cells). Upload the modified setup data.
5. Operate the motorcycle under varying conditions.
Use TCFI Log or TCFI View software to examine
3. Front cylinder trim. This procedure is required for all engines with siamesed runner throttle bodies or
2-into-1 exhaust systems.
5. Spark knock. Verify absence of spark knock during throttle roll on and wide open throttle acceleration.
FUEL INJECTOR SIZING
Accepted engineering practice is to use the smallest possible injectors (in terms of flow) for best control at idle and part throttle. The Delphi
®
style single throttle body and similar aftermarket units with siamesed runners are subject to fuel imbalance problems between the front and rear cylinders. When the fuel injector duty cycle approaches 50%, fuel will start being inducted into the wrong cylinder (i.e. front injector spraying fuel while rear intake valve is still open). Front cylinder trim cannot correct this
problem. Aftermarket throttle bodies with dual independent runners do not suffer from this problem and the fuel injectors can be run up to 80% duty cycle.
At high duty cycles, fuel may puddle up in front of the intake valve but will ultimately be inducted into the
® correct cylinder. Stock Delphi injectors are rated at approximately 4.2 gm/sec flow. We offer larger injectors rated at 6.0 gm/sec. Table 1 lists the
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maximum possible horsepower based on injector size and type of throttle body.
Table 1 – Maximum Horsepower Limits
Injector Size Siamesed Runners Dual Runners
4.2 gm/sec
6.0 gm/sec
75 HP
110 HP
135 HP
195 HP
WARNING: If you exceed these horsepower limits, front cylinder trim will fail. The result will be a lean cylinder and possible engine damage at high RPM wide open throttle.
LARGE DISPLACEMENT ENGINES
For large displacement engines and/or higher flow injectors, you can modify the 95 CID setup file
(TCFI_Setup95.dat) by editing the module parameters and entering appropriate values for the estimated engine horsepower and injector flow rate.
The TCFI has been successfully applied to engines as large as the S&S Cycle 145 Tribute.
Engines over 103 CID may require additional tuning procedures, such as increases to the priming and cranking fuel tables. Please contact our tech support for details.
THROTTLE BODY AND INTAKE
RECOMMENDATIONS
95 CID or higher displacement engines will require an aftermarket throttle body and low restriction air cleaner for maximum performance. We recommend a throttle body with at least 50 mm ID. Smaller throttle bodies or modified stock throttle bodies will not allow sufficient air flow at high RPM. This can be verified by examining MAP (manifold pressure) during a dyno run with TCFI Log software.
Front cylinder fuel imbalance may become intolerable with large displacement engines unless a dual independent runner intake and throttle body system is used. We have tested BC Gerolamy Dual
Flow and S&S Cycle VFI Induction systems. If you plan on using another dual runner type system, please contact our tech support before proceeding.
BC GEROLAMY DUAL FLOW
THROTTLE BODY
Follow the installation instructions supplied with the throttle body. You can use the stock Delphi injectors for applications up to 135 HP. Use the setup file TCFI_Setup95_Gerolamy.dat. This setup file is intended for a 95 CID engine. For large displacement engines, you can modify this setup file by editing the module parameters and entering an appropriate value for the estimated engine horsepower and injector flow rate.
S&S CYCLE VFI INDUCTION
SYSTEM
The TCFI has been successfully retrofit on many problematic VFI systems. Most VFI systems have injectors rated at approximately 4.6 gm/sec flow that are capable of supporting engines with up to 150 HP.
Follow the installation instructions supplied with the VFI system, with the following exceptions:
1. Some early production units have undersize idle air ports. All idle air ports leading to and from the IAC control must be at least 0.312” diameter. If required, mill ports to 0.312” diameter in a
Bridgeport mill (do not attempt to use a drill). Tilt the milling machine head to match the angles of the idle ports. Remove the TPS sensor to facilitate clamping the throttle body in a vise.
2. When installing the VFI Induction, disregard the
S&S Cycle instructions related to idle stop and
TPS adjustment. Follow the procedures we give on pages 2-3.
3. Carefully check wiring connections. All OE H-D
® signals (refer to H-D
®
Electrical Diagnostic Manual) must be connected. Common problem areas include failure to connect the vehicle speed sensor
(VSS) signal. Some VFI applications did not use a manifold absolute pressure (MAP) sensor. The
TCFI requires a MAP sensor ported to the front cylinder intake runner.
4. Use the setup file TCFI_Setup95_VFI.dat. This setup file is intended for a 95 CID engine and the
S&S Cycle injectors supplied with the VFI Induction
System. For large displacement engines, you can modify this setup file by editing the module parameters and entering an appropriate value for the estimated engine horsepower.
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IDLE TUNING CONSIDERATIONS
Some large displacement engines with high overlap/long duration camshafts may not idle properly at the nominal 1000 RPM and 13.0 AFR settings used in the standard setup files. You may have to increase the idle RPM to a higher value such as 1100 RPM and enrich the idle to 12.5 AFR.
Use the Edit 2 D Table – ET Based Idle RPM function to increase the idle RPM. Do not decrease values at the left of the table (corresponding to a cold start condition) that are already higher than your desired idle RPM. If you significantly increase idle
RPM, you may also have to make corresponding edits to the ET Based IAC Position table. Please contact our tech support for details.
Then use the Edit 3D Table – AFR Table function and change the six cells near idle (500 -1250
RPM and 0-2.5% TPS) to 12.5 AFR.
DYNO TUNING CONSIDERATIONS
We do not recommend auto-tuning on a dyno.
When vehicle and engine manufacturers conduct tests in EPA certified facilities, federal regulations require that the cooling air velocity at the front of the engine be closely matched to roll speed using a computer controlled variable speed fan drive. Present generation
Dynojet load control systems used for aftermarket tuning lack this level of sophistication and are incapable of simulating realistic on-road operating conditions over an extended period of time.
On-road auto-tuning using the procedures listed on pages 4-5 will get you within a few horsepower of the maximum that the engine can deliver. If you decide to do dyno tuning for maximum power, you can experiment with wide open throttle (WOT) ignition timing and AFR. Please pay careful attention to the following dyno tuning considerations:
1. Only edit the ignition advance and AFR tables.
Don’t edit any other tables (never make any changes to the BLM or Alpha-N tables once autotuning is completed). The usual range for WOT ignition timing at 4000-6000 RPM is about 28-34 degrees BTDC. The usual range for WOT AFR is about 12.5-12.8. Some engines may require a richer mixture, possibly down to 11.5, to avoid detonation problems.
2. The TCFI should be operated in closed loop.
Make sure that the engine is warmed up (no cold engine status in TCFI Log or TCFI View) and that the oil temperature is in the 150-180° F range before doing a run. If you have made any table edits, allow one run for auto-tuning before capturing data.
3. Engine warmup. The normal engine warmup time setting (Module Parameters) results in a delay of
180 seconds before closed loop every time the engine is started. During dyno testing, you may want to reduce the engine warmup time to 90 seconds and the warm engine temperature to 75°
C. This will move the testing process along and also avoid potential engine overheating problems while waiting for closed loop.
4. Inadequate air flow for engine cooling is a
major problem with many dyno systems.
Always let the engine cool off between dyno runs.
The use of a separate heavy duty industrial grade fan capable of generating at least 50+ MPH air velocity at the front of the engine is recommended.
You can measure the air velocity with a handheld anemometer such as Extech P/N 45118 available from Grainger.
5. Use the TCFI data logging capability. Set the data logging interval to 0.1 seconds. Always download data with TCFI Log software at the end of every run and study the results. Check engine and air temperatures, throttle position, manifold pressure, and AFR. TCFI Log is a very powerful tool that can help you identify potential problems that may be affecting engine performance.
Inconsistent dyno test results are often the result of thermal problems (engine temperature variations or hot soak effects).
6. Dyno exhaust sniffer limitations. Some of the older sniffers monitored CO and CO2. These systems are so slow and inaccurate that they should be totally disregarded. Modern sniffers from
Dynojet and Horiba use a wideband sensor similar to the WEGO sensor. These sniffers are still subject to erroneous lean readings caused by reversion of atmospheric oxygen if the probe cannot be inserted past the baffles in the exhaust.
Sensor degradation caused by leaded racing gas is a common occurrence. Another problem is sampling delay due to the long hose between the sniffer tip and actual sensor. The bottom line is to trust your WEGO and doubt any discrepant readings from an exhaust sniffer.
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ENGINE TUNING GUIDELINES
Higher AFR values correspond to a leaner (less fuel) condition. The practical operating range for most engines using gasoline fuel is from approximately 11.5 to 14.7 AFR. Combustion of a stoichiometric mixture
(exactly enough air to burn all the fuel) results in 14.7
AFR indication. Automotive engines with catalytic converters operate near 14.7 AFR during cruise and idle. Air-cooled motorcycle engines usually require a richer mixture to limit cylinder head temperature and prevent detonation. Table 2 lists recommended AFR values for engines without emission controls.
Table 2 – Recommended AFR Values
Operating Mode Recommended AFR
Cold Start (first 30 sec) 11.5-12.5
HOT STARTING PROBLEMS
Some Twin Cam 88 engines are prone to hot starting problems. When cranked after a short hot soak, the engine may “kick back.” Over time, this will cause damage to the ring gear and starter pinion.
The TCFI module uses an improved starting algorithm that includes a programmable cranking delay. The TCFI module is shipped with a zero cranking delay: it fires on the first recognized compression stroke. This works best on stock and mildly modified engines.
High compression engines will generally require compression releases. When compression releases are installed, best starting results will be obtained by programming the TCFI module for a 1-2 revolution cranking delay. This can be done by means of the PC
Link TCFI software.
Idle 12.8-13.5
SPARK KNOCK PROBLEMS WITH
Part Throttle Cruise 13.0-14.0
HIGH COMPRESSION ENGINES
Wide Open Throttle 12.5-12.8 (values down to 11.5 may be used to reduce detonation)
Spark knock problems may be encountered with high compression engines. If engine parts were “mixed and matched” from different suppliers, the actual compression ratio may differ substantially from the expected value. You cannot estimate compression ratio with cranking compression tests, as camshaft timing usually causes an erroneous low reading.
EXHAUST CONSIDERATIONS
The use of a WEGO system for closed loop fuel control places constraints on the choice of exhaust system. The WEGO system may give inaccurate results in certain situations:
To accurately calculate compression ratio, you must measure the combustion chamber volume and use the formula:
Compression = (Head cc + Deck cc + Cylinder Volume)
Ratio (Head cc + Deck cc)
Exhaust reversion. Reversion is the term for a negative pressure wave that can suck ambient air back into the exhaust and cause an erroneous lean AFR indication. Open “drag pipes” usually suffer from reversion effects and may not be suitable for use with the WEGO. Reversion effects will also occur with certain exhausts used on “bagger” style motorcycles, where two pipes split off near the rear cylinder. At part throttle, air is actually sucked into the left tailpipe. You will have to block off the left pipe. Reversion effects will be most noticeable at idle, part throttle low RPM cruise, and decel.
The practical limit for compression ratio is about
10.5:1 to 11:1 when running 93 octane pump gas. Any higher compression ratio will require retarding the ignition timing to the point where more power is lost from the retarded timing than is gained from the higher compression.
If spark knock is encountered during operation, you can use the TCFI Log software to download data and examine the operating conditions (RPM and
Excessive scavenging. Tuned exhausts in combination with a high overlap camshaft profile can pull unburned air and fuel mixture through the cylinder into the exhaust and cause an erroneous rich AFR indication. Some aftermarket 2-into-1 systems, such as the Thunderheader appear to suffer from this problem, whereas others such as the Vance & Hines Pro Pipe and White Brothers E-series seem less affected.
CAUTION: Insistence on using a cosmetically pleasing but inappropriate exhaust and consequent failure of autotuning is a major cause of installation problems requiring tech support.
Daytona Twin Tec LLC, 933 Beville Road, Suite 101-H, S. Daytona, FL 32119 TCFI Gen II Tuning Manual
(386) 304-0700 www.daytona-twintec.com
4/2005
Page 8
manifold pressure) where spark knock occurred. You can then make appropriate reductions to the ignition advance table.
USER FUNCTIONS
The TCFI user input on pin 23 can be connected for a stage RPM limit function as shown in Figure 1.
The stage limit switch must be normally open. You can use a microswitch attached to the clutch lever. When the clutch lever is pulled in, the switch contacts should close to activate the stage RPM limit. Refer to the User
Functions section of the PC Link TCFI instructions for details on programming the stage RPM limit.
Figure 1 – Stage Limit Switch Wiring Diagram
TCFI Gen II
TO +12V PIN 23
STAGE LIMIT SWITCH OPERATION:
SWITCH OPEN - MAXIMUM RPM LIMIT
SWITCH CLOSED - STAGE RPM LIMIT
The TCFI user output on pin 22 can drive a standard automotive relay connected as shown in
Figure 2. When the user output is active, +12V power is applied to the load. Refer to the User Functions section of the PC Link TCFI instructions for details on programming the user output.
Figure 2 – User Output Relay Wiring Diagram
TO +12V
TCFI Gen II
PIN 22
86
87
30
85 12V STANDARD
AUTOMOTIVE
RELAY
TO LOAD
UPGRADES AND KNOWN ISSUES
The TCFI controller can be upgraded in the field by the user. Operating firmware is stored in FLASH memory and new firmware can easily be uploaded by means of the PC link cable. We suggest you periodically check our website at www.daytona-twintec.com
for upgrades to the TCFI firmware and accompanying PC based software.
The TCFI system is new to the marketplace and as with all complex new computer systems, unforeseen issues may occur. As of the shipment date, there are no known issues other than those listed below.
Barometric pressure compensation.
Barometric pressure is always read at engine start. For operation in mountainous terrain with elevation changes of more than 3000 feet, you can select the
Continuous Barometric Pressure Update option in
Module Parameters. When this option is selected, barometric pressure will be estimated from manifold pressure sampled at specific crank angle and TPS conditions. This option is new to the TCFI Gen II version and the effect of aftermarket camshafts, throttle bodies, and air filters has not been fully evaluated.
TSSM module trouble code. Installation of the
TCFI may set a TSSM module trouble code. This may cause the turn signals to momentarily blink and the security LED to light up for several seconds when the engine is started. The turn signals and security system will continue to function normally.
Possible firmware corruption during dyno
test. We suggest that you do not connect the PC link cable to any PC running Dynojet WinPEP software.
Use a separate PC, such as a laptop with isolated ground. There appears to be a serial port conflict or noise issue from the Dynojet ignition pickup.
CUSTOM BIKE CONSIDERATIONS
The TCFI can be used for custom bike applications. The TCFI also has special features to accommodate aftermarket speedometers and tachometers, even on 2004-2005 H-D
®
models with the
J1850 data bus. The TCFI does not require the presence of a turn signal/security module
(TSM/TSSM). However, it does require all the engine sensors and actuators used with a standard H-D
® application, including a vehicle speed sensor (VSS).
Prior to installation on a custom bike, we suggest that you contact our tech support.
Improper wiring connections, with missing or incorrect signals, are the most common problem encountered with custom bike applications.
Daytona Twin Tec LLC, 933 Beville Road, Suite 101-H, S. Daytona, FL 32119 TCFI Gen II Tuning Manual
(386) 304-0700 www.daytona-twintec.com
4/2005
Page 9

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Key features
- Wide-band exhaust gas oxygen (WEGO) sensor interface
- PC Link TCFI software for tuning
- TCFI Log software for data logging and analysis
- TCFI II View software for viewing engine parameters on a PDA
- Auto-tuning feature
- Front cylinder trim procedure
- Stage RPM limit function
- User output for controlling external devices
- Barometric pressure compensation
- Custom bike compatibility