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Swapping a 08 Civic SI into 07 fit

Posted: Thu Sep 18, 2014 10:44 pm
by K24Zivic
I am swapping the complete drivetrain and engine from a 08 Civic SI into a 07 Fit. I have modified the original fit engine harness into the K20 engine assembly, that's pretty straight forward. My concerns are at the ECU end. I will be using both the Civic and Fit ECU. I will be using the drive by wire throttle and A/C. I basically need some help to confirm my logic.
1) Fit ECU controls drive by wire
2) throttle signal needs to be split between both for fuel mapping and cruise control
3) Coolant temp goes to both to maintain coolant light on dash
4) Immobilizer system will be deleted with flash pro?
5) install 2nd OBD plug for flash pro to Civic ECU
6) wire second cam sensor and VTC solenoid using EGR wires in Fit harness and pin to Civic ECU
7) use Evap purge control wire for reverse lock out solenoid and pin to Civic ECU
8) Vehicle speed signal will have to converted to low frequency signal and pined to Fit ECU for speedometer or does the Civic speed output come out at low frequency?
9) Engine RPM signal from Civic to Fit ECU
10) change coil plugs to K coil plug
11) splice MIL out from Civic to Fit ECU
12) Alternator signal split to both?
13) starter relay signal remove from Fit ECU and pin to Civic
14) Oxygen sensors, camshaft, crankshaft, intake air temp, MAP, VTEC oil, VTEC solenoid and VTC solenoid go strictly to Civic ECU
15) Reverse light switch and oil pressure switch go to Fit ECU
16) battery, main relay power, switched power and grounds split to both

Think that's about it, right? This way flash pro will work and all factory Fit CAN protocol is working for gauges, lights, etc.

Should I install diodes anywhere? There isn't much if anything on the specifics on the electrical side of this swap. The engine assembly is in the Fit already, I just have to figure out how to make it work like OE from the drivers seat. Any help would be very much appreciated.

Re: Swapping a 08 Civic SI into 07 fit

Posted: Fri Sep 19, 2014 9:13 am
by Spunkster
This is not a swap we recommend or support. You do this at your own risk. You may have a number of issues with getting this to work.

Re: Swapping a 08 Civic SI into 07 fit

Posted: Sun Sep 04, 2016 6:12 pm
by 345GE8RS
Hey, Did you end up getting the swap completed??

Re: Swapping a 08 Civic SI into 07 fit

Posted: Mon Sep 05, 2016 8:45 am
by K24Zivic
Yes, and it runs daily.