K20A/A2/Z1/K24A2 into 02-04 RSX Base Wiring, ECU, & Misc. Swap Details

I normally wouldn’t care about this specific swap as I don’t own an RSX or any of the newer 02+ generation Honda/Acura’s. I can’t stand those chassis’s! But this became a topic regarding a friend of mine who performed an ’07 K24A2 swap into an ’03 Base RSX…AUTO at that. Auto converted to manual. For some reason its running like doo-doo and wants my help in figuring out wtf is up with it. I have yet to see whats wrong with it but I’ve been researching what’s required in performing a Type-S or TSX swap into an RSX Base.

What I’ve learned thus far…

  • If reusing a Base RSX engine harness…
    (1) TPS outer wires needs to be swapped around in order to correct wiring orientation for Type-S throttlebody use
    (2) Wiring for 6spd reverse lock is required (more on this later)
    (3) Underdash wiring for auto trans shifter needs to be modified and set for ‘neutral’ or else vehicle will not start for manual conversion.
    (4) Immobilizer bypass required if KPRO is not being used
  • If using a Type-S engine harness & ECU, no wiring mods required..
    (1) This is allegedly all 100% plug-n-play for a Type-S swap respective to year (02-04 & 05-06)
    (2) Immobilizer bypass required if Kpro is not being used
  • K24A2 swap requires specific attention..
    (1) Using a Type-S engine harness is fine but its best to use a Type-S or reuse the RSX Base crank sensor as the K24A2/TSX crank sensor uses a different connector and pin configuration and will cause issues if not corrected.
    (2)Immobilizer bypass required if KPRO is not being used. TSX ecu is incompatible with an RSX because it requires a Drive-by-Wire driven throttlebody system.
    (3) Adaptation of a Type-S throttlebody to K24A2 intake manifold (or RBC/RRC) is required via throttlebody adapter plate.
    (4) If using a Type-S “PRB” ecu to power the K24A2, it’s best to switch the intake VTC cam gear to a Type-S or K20Z3 VTC gear to obtain 50-degrees of VTC which the factory programmed PRB ecu is programmed to use. Stock K24A2 VTC gear is limited to 25-degrees. The stock PRB ecu can run the K24A2 engine but it’s best to move up to a KPRO and run the proper calibration for a K24A2 engine until you can get around to dyno tuning. PRB programming is made for a 2.0liter engine so its lacking the fuel/timing/and VTC maps for a 2.4liter…2 different beasts.
  • Type-S primary 02 sensor is required (Base primary 02 is not a wideband unlike a Type-S primary 02).

Easiest method is to run a Type-S engine harness (w/crank sensor), ECU, Primary 02, with transmission as it is all pre-set for 6spd use. No real fumbling around is needed for a Type-S/Type-R/K24A2 swap.

The K20A3 engine uses smaller size injectors (270cc) vs. Type-S + TSX engines (310cc). The injector size is programmed into the factory ecu programming. So, make sure you don’t reuse K20A3 injectors on a Type-S or TSX engine swap as the engine will run like crap when using a factory PRB  ecu or are KPRO’ing at a later time.

Other Swap Notes

  • Base RSX cruise control cable is a tad short for a Type-S swap and tends to keep the throttle body butterfly open just enough where the idle will stay high. Switching to a Type-S cruise control cable is the fix for this.

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