Hondata

Civic EJ1 K20
- version: 4.6.1.0 Build 4083
- PRB ECU

- 52mm ITB, Alpha-N tune.
- Hall effect TPS calibrated.

Injectors cuttoff on very light throttle,it creats an anoying jerking of the car.
This always occurs between 1% and 3% TPS.
Regardless of RPM or VSS.

What could be the problem?
I have already tried to cancel the cutoff in advanced parameters, but no solution. It's remains the same problem.

Callibration and Datalog attached.

Do you have a vacuum accumulator with the MAP connected to it?

Yes! I have attached a photo.

For information, at idle, the car remais at about 48~50 kPa (7,2 PSI)

Have you discussed this issue with your tuner?

Spunkster wrote: Tue Jun 23, 2026 4:28 pm Have you discussed this issue with your tuner?

I'm the tuner, i did the calibration myself,

I have already tried several thins to fix this issue, it's not a new problem in my car,

Things checked/tried to cancel cutoff:
- Checked tps callibration voltage (0-100%)
- Change parameters in "advanced-Overrun cutoff low cam" tab, to a MAP value higher when in idle/light throtlle
- Changed overrun cutoff min rpm to 4000 RPM

The last thing that i think i could change is toggleing the box "Disable fuel over-run cutoff delay" in closed loop tab. But to me, checking this, will go rith in the opposite direction of my issue. Could i be wrong?

You might want to talk to a tuner that is familiar with tuning ITB's and see what they say. ITB's are really only good for wide open throttle use for racing and not ideal for daily driving and part throttle.