VTEC Activation - K20A2 EK Swap

K-Series Programmable ECU Calibration updates / downloads
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jmr302
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Joined: Sat Feb 07, 2026 4:14 pm

VTEC Activation - K20A2 EK Swap

Post by jmr302 »

I am sorting out a K20A2 swap in an EK hatch that someone else built. Currently I have 3 main issues:

1) VTEC activation
VTEC works initially but stops working a couple of blocks from home. Log files show that the ECU stops commanding it. If we key off-on, VTEC is functional again for the same brief period of time.

2) Low idle speed
Warm idle speed is normal initially (750 rpm), then drops to 500-600 rpm a few blocks from home. Key off-on resets this, just like the VTEC issue. S.TRIM is high in both conditions. AF ratio cycles very lean when the low idle speed occurs.

3) VSS signal
The speedometer is fully functional at all times but the ECU shows 0 mph. Occasionally it will register 3-5 mph. Cycling the key does not affect this.

The engine is a bone stock K20A2 with a header and CAI. Trans is a base model RSX 5-speed. Could this account for the VSS issue? It runs decently on this ECU calibration except for the problems listed. Any help would be appreciated. Thank you!
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CalibratEd
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Joined: Fri Feb 07, 2020 3:20 pm
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Re: VTEC Activation - K20A2 EK Swap

Post by CalibratEd »

I have not looked over the logs as I am away from my computer. I would say you may be experiencing an electrical issue. To start I suggest you set the VSS to constant speed to rule out a bad VSS. If the VSS is not working well Vtec will not engage.

I also suggest you make sure to calibrate the TPS.

I’ll have better insight once I look over the calibration file and logs.

-Ed
Instagram: calibrated.tuning
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