TFI Installation 
(includes Techlusion, Dobeck, Thunder & RevTech)
Gadget

tfi1.jpg (59577 bytes)


Need a little more punch from that 1500 or 1600 cc V-twin?   The most bang for the buck will come with an aftermarket air cleaner replacement.   There are dozens of designs available, all will flow a lot more air to the cylinders.  That creates a problem with our fuel injected bikes.  The computer is mighty dumb and, with no 02 sensor in the exhaust to determine whether the air/fuel mixture is correct, will just keep pumping the same amount of fuel into cylinders based on the air temperature, coolant temperature, throttle position and barometric pressure the factory programmed into it.   The result, a lean running engine, perhaps dangerously so depending on your mods.

The solution, an aftermarket computer that will boost the amount of fuel being injected.  Like air cleaners, there are several of these available too.   This guide will be for the installation of the Dobeck TFI (and branded copies) but will probably be similar for the Cobra FI 2000.  

The Techlusion TFI may be the best type of assistant for street use.   Racers and those who want the absolute maximum performance from their engines in every rpm range should purchase the Thunder Power Commander (PC) instead.  The PC can be programmed using a laptop computer while the bike is running on a dyno.  Different air/fuel mixtures can be programmed for every 250 rpm and the front/rear cylinders can be programmed individually.  All you need is a competent tuner.

The TFI (and Cobra 2000) can only make the mixture richer but for most aftermarket mods (intake/exhaust) this is exactly what is needed anyway and they're adjustable by ordinary humans.

If you have already installed your TFI check here for rider settings you might want to try.

So, to the install


What You'll Need

TFI   unit.  Prices vary from about $125 to $189 so work with your supplier on that
Soldering iron & solder (if you want to do it right)
Phillips screwdriver
small flat blade screwdriver
wire cutters/wire stripper
electrical tape
1 foot (or so) of 1/4" heat shrink tubing

My first suggestion will be to throw away the wire clips supplied with the TFI unit.  Yes, they make the install simpler but those clips have been the source of many electrical problems on motorcycles.   Soldering your connections would be far better.

1a. Decide where you want to place your TFI unit.   Most riders put it behind the left side cover but if, like me, you've run out of space behind that cover with a cruise control, yellow box, emergency flasher and other 'stuff' your options will be narrowed a bit.    I ended up placing mine under the rear fender trim which turned out to be a pretty handy spot for tuning too since access is easy (no side cover removal each time you want to tweak the unit).   Once you have your preferred location (it won't go under the seat, trust me on this one) go to step 1.

1. Remove your seat and set it aside in a safe spot

2. If you'll be installing the unit under your left side cover remove the cover

3. Disconnect your negative battery cable (this is just a safety measure that should be taken whenever you're working on the bikes electrics.

4. Place the TFI unit in the location you've selected and carefully run wires under the frame and into the battery area.  It is suggested you use shrink tubing around the wires just to keep the together and for a neater installation.

4. Using your Phillips screwdriver remove the screw holding the metal battery strap in place and remove the battery strap

5. Carefully lift the ECU from its spot to the left of the battery.   Note the orientation so you won't have to play the puzzle game when it's time to slip it back in place.

6. Note for 1500 FI's one of the plugs on the ECU is white, the others black.  On 1600's there is just one plug with a 'bunch' o' wires.  Don't let this confuse you, the colors for the injector wires are the same.  Measure the amount of TFI injector wire (blue and gray) you'll require to reach that white connector and add a couple of inches for safety.   It is advisable to remove both of the larger plugs (with wires) from the ECU and set it aside in a safe spot.   You 'can' do this without unplugging anything but..that's a mighty expensive part to have teetering on the edge of the frame.

7. Check out the white plug and find the two wires (you may have to cut the harness tape back a bit) that go to the fuel injectors.  Those are the blue with red stripe and the blue with green stripe.  They are right next to each other.   If you're a guy prone to color blindness you won't be able to see the green stripe against the blue wire.   Get help from someone who 'can' see the green stripe before stripping any insulation.

8. If you have decided, against expert advice, to use the supplied clips then go ahead and clip the gray and blue wires from the TFI to the injector wires (it doesn't matter which goes to which).   Wrap in electrical tape to prevent vibration.

10. If you have decided to follow the expert advice, strip about 1/4-1/2 inch of insulation from each injector wire, strip about 1/4-1/2 inch of insulation from the end of the gray and blue TFI wires and tightly wrap them around the injector wires.  Solder them in place and wrap individually with electrical tape.   Wrap the entire harness including your newly soldered connections in more electrical tape.

11. Replace the plugs on the ECU if you disconnected them making sure you plug them into the correct sockets.  It is apparently 'possible' to swap the white and black plugs and the result will be an engine that doesn't start, a fuel pump that doesn't run and...well, a dead bike.

12. Put the ECU back in it's nest and replace the battery hold down.  

13. Connect the red wire from the TFI to the red tail light wire under the seat.  You'll want to check the wire to make sure you see battery voltage when the key is on before stripping insulation.    You're choice whether to use the supplied clips or do it the right way and strip back a bit of insulation from the red bike wire and solder the red TFI wire to it.  In either case wrap the connection with electrical tape.

14. Connect the black TFI wire to one of the accessory ground leads under the seat using a standard bullet connector.  If you haven't used these before they're likely to be tucked down between the ECU and the frame on the left side.  The ground connectors are the ones with black/yellow wire.   The other connector you'll find there is a colored wire (usually red/blue) and is unswitched battery power.

15 Tidy up your wiring using zip ties where necessary.

16. Remove the rubber plug from the face of the TFI unit and note the four potentiometers.  These will be used to adjust your fuel mixture.  First though turn on the key and make sure the green light inside the unit is blinking.  This indicates all of your connections are properly made.    Start the bike and the green light should stay on solid.   If so then it's time for the adjustments.  If there is no green light you'll have to go back to square one and figure out what went wrong.

17.  The TFI unit came with instructions showing a recommended 'starting' point for settings.   Go ahead and, using your very small flat blade screwdriver (and reading glasses if you're over 40), carefully turn each pot to the location shown in the instructions.  For Nomad that is 2:30 for the green (1st) pot, 2:00 for the yellow (2nd) pot and 0 or off for the red (3rd) pot.   This is for an unmodified or lightly modified (maybe you've just replaced the goat belly with a bypass pipe) engine.    The 4th pot tells the unit when to segue from the 'idle/cruise' mode to the higher power (red) mode.   Set this at 9:00 for the transfer to take place at 4000 rpm.  Lower if you want it to transfer earlier than that.   Keep in mind 4000 rpm is 48 mph in second gear, 64 mph in third gear, 79 in 4th and nearly 98 in 5th.  Set the RPM pot lower than 9:00 and you could be enriching the mixture at normal cruising speeds and wondering where your fuel mileage went.

18.  Follow instructions that come with the TFI unit for setting the first  pot (engine warmed and idle smooth) then go for a ride to adjust the others to your liking.   For #2 start at the recommended setting and see how the engine pulls through 1st and 2nd gear.  Adjust one step higher and ride again.  Keep going until your 'seat o' the pants' dynometer says it's running best.   If another rider can follow you during those roll on tests they can tell you when black smoke (indicating a rich mixture) comes from the exhaust during roll on so you can back off the #2 pot a bit.

19. Adjusting the 3rd pot can be a little more time consuming (oh darn, you have to ride more) but keep dialing it up one step at a time until there is no full throttle (past the point you set #4 at) improvement.  In reality this third pot can only be set correctly on a dyno. If you can find one at a bike shop near you pony up a few bucks and buy the 15 minutes or so it'll take to set things up properly.

20. After riding awhile check your spark plugs to be sure you aren't running rich remembering TFI and Cobra's FI 2000 can 'only' richen mixtures, not lean them out.

Settings

The following are TFI and Cobra pot settings being used by riders.  The type of intake/exhaust and other mods are shown so you can compare with what you are using.   There are no guarantees these settings are the 'best' for your bike and equipment, only starting points for you to try.  

On the TFI Pot #1 is called the "idle' jet pot and is the one most responsible for mixture from idle through midrange.   Pot #2 is the 'accelerator pump' pot and acts just like the accelerator pump in a carburetor adding some extra fuel when you first roll on the throttle.   Pot #3 is the 'main jet' pot and takes over at higher rpm.   Pot #4 determines at what rpm the 'main' pot comes on.   The recommended setting (for a TFI) is  9:00 which is 4000 rpm.   Setting the fourth pot to 9 keeps enrichment from the #1 pot coming on until that 4000 rpm threshold is reached.  After that the stock ECU is providing plenty of fuel. 

Brand Settings in order pot 1,2,3,4 Equipment
Dobeck
TFI
Dyno
Settings
2:15  2:45  1:00(off)  9:00 '01 Nomad 1500 engine stock, Thunder (Odyssey) intake, Vance & Hines Bagger Exhaust

This TFI setting with this equipment resulted in a perfect 13:1 to 14:1 mixture across the entire rpm range while accelerating (hard) and while cruising at steady speeds on a Dynojet Dyno

RevTech DFO 2:30, 3:00, 1:30, 9:00 2002 VN1500 Classic, Hypercharger, Cobra Drag Pipes.  .
RevTech
DFO
2:30, 3:00, 1, 9
'04 1600 Classic
V&H ProPipe
Left side open air with K&N E-2605-1

Dobeck
TFI
3, 3, 1, 4 Classic 1500 Thunder round intake, V&H longshots
Cobra FI2000 2.5, 6.0, 1.0 2005 Nomad 1600
V&H Baggers
Coasters (Reed Valves Removed)
Caddman Kit / with K&N Filters (There was a difference between the paper filters and the K&N filters. The performance was much better with the K&N.)
Cobra FI2000
Dyno
Settings
1, 1:45, Off 2001 Classic . 
Cobra slashcut deluxe exhaust, original kuryakyn
hypercharger, reed valves intact
Dobeck
TFI
2.30,  3:30, 1:45, 9:00 
'00 Nomad FI 1500 w caddmann & V&H Baggers
Dobeck
TFI

2:30, 3:00, 1:30, 9:00 

1500 Classic Thunder round air & V&H Straightshots 
Dobeck
TFI
 2, 6, 2, 4:30 03 Mean Streak, Vance & Hines Long Shots, Thunder Air Kit (Fluted Tear Drop)
{Gadget note: This rider is probably running very very rich with the main jet coming in so early}
Dobeck
TFI
 2, 2, 1, 11 1500 engine, K&N teardrop and Bubs crossdressers
Dobeck
TFI
 3, 3, 1, 11 Classic 1500, Sherm's 'Sleeper' air box, V&H Dual Baggers