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Decided to fix the servo removal problem for you guys *Quick and Easy FI Light Fix*

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142K views 235 replies 108 participants last post by  smaragdsoft  
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#1 ·
I got tired of eveyone saying it's impossible so here you go:

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I've not given a super in depth testing, just riding around the block at different throttle settings and RPM ranges. EFI light didn't turn on, also checked the voltages sent to the ECU and they look good.

Here is what happens: The red and blue wires are connected to the motor and switch poles to move the exhaust valve. The feedback is a potentiometer, the green wire is ground and the yellow/red is +5V. The brown wire is the input to the ECU.

When the red wire is energized the motor spins in the direction that increases voltage to the signal (brown) wire. Therefore I set the red wire to charge the capacitor (220ohm resistor there to limit how fast it chargesit, could overshoot without it). If it needs to move the valve the opposite way the red wire goes to ground and will lower the voltage in the capacitor. This replicates the pot moving the opposite direction. The 4.7k ohm resistor is simply there to protect the input line incase you hook things up wrong and send 12V into it.

These are the components I had sitting around and can be varied. These are all common values for these components however.

Enjoy.
 
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#5 ·
Darth said:
Why not do what Ivan does for the yamahas and build your own servo motor eliminator kit, plug and play. You'll probably sell every single track day guy one starting with me.
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I guess I could, if I could find a place to buy that plug. Probably would be best for one of the vendors on here to puck it up since they have all that payment stuff setup. I'm an engineer, I can build the stuff but selling isn't my thing :)
 
#4 ·
The exhaust servo controls the exhaust valve further up from your S/O towards the header. When you install a full exhaust or replace the header, the valve goes away so you typically have to undo the cables up to the exhaust servo. You can't remove it as it would throw an FI light. The OP has come up with a way to trick the ECU into thinking the servo is still there so that you can remove it. This would be more for those that race/track their bikes and are looking for every ounce of weight savings possible.
 
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#6 ·
i musy say i'm impressed. now just show me a dyno chart to confirm it.
 
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#13 ·
Yeah as long as the HESD light isn't coming on there will be no issues with power loss. Either its in limp mode or it isn't.

I believe the connector is not exclusive to Honda even then the unit you make doesn't have to have the factory connector you can leave it with the wires loose and the user can solder it up to the factory connector.
 
#26 · (Edited)
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#29 ·
RShackleford said:
hi,

i have a quick question about your servo removal fix.



i cant find a 470 micro farad capacitor anywhere.

i found 47 and 4.7s and even a 4700 but no 470



where did you locate these components.



radio shack said that if they had a part #they could order one but even they couldnt find a 470 in their computer.



thanks
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I pulled the capacitor and resistors out of an old alarm system :)

The 47uF would probably work as well. I would get one as close to 470 you can find though since that is known to work. The exact value is not critical the capacitor simply acts as a buffer. the voltage is also not critical as long as it's rated 12V or greater. You can use other types of capacitors as well, there is no discernable difference (just make note of polarity on the capacitor) for this application. If you want to encase everything in silicon or similar I would suggest a tantalum or other sealed capacitor.
 
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#32 ·
easy fix
go get universal connectors from radio shack male and female and use them instead.
all it will require is to cut the oem plug off and put the radio shack plug in its place.

i just made this thing.
here is a picture of it next to the original servo motor.
look at all that space saved. plus the servo motor weighs right at 3/4 lb. its not a lot but i have whittled away an ounce here and and ounce there and ended up knocking the wet weight down to 370lbs. well now i am just under 370 wet.
i am not using connectors, i am just soldered it in. so far it works great. idled for about 10 mins in the garage with no lights or problems.
Image
 
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#36 ·
RShackleford said:
easy fix
go get universal connectors from radio shack male and female and use them instead.
all it will require is to cut the oem plug off and put the radio shack plug in its place.

i just made this thing.
here is a picture of it next to the original servo motor.
look at all that space saved. plus the servo motor weighs right at 3/4 lb. its not a lot but i have whittled away an ounce here and and ounce there and ended up knocking the wet weight down to 370lbs. well now i am just under 370 wet.
i am not using connectors, i am just soldered it in. so far it works great. idled for about 10 mins in the garage with no lights or problems.
Click to expand...
Great to hear you got it working!
 
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#54 · (Edited)
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