Honda-Tech - Honda Forum Discussion

Honda-Tech - Honda Forum Discussion (https://honda-tech.com/forums/)
-   Honda Prelude (https://honda-tech.com/forums/honda-prelude-4/)
-   -   Knock Board Delete CEL on all the time no code flash (https://honda-tech.com/forums/honda-prelude-4/knock-board-delete-cel-all-time-no-code-flash-3381203/)

AceViolent Apr 24, 2025 02:48 PM

Knock Board Delete CEL on all the time no code flash
 
I successfully did some soldering and removed the knock board of my car's ECU, as well as bypassing the AT so it works with the MT. I plugged it in and it runs the car, but the Check Engine light is on with no code flashing. Is this an expected side-effect of the deletion? I jumped the service plug and get nothing from it. It's just on constantly.

1992 Prelude Si, F22B DOHC

JRCivic1 Apr 24, 2025 08:41 PM

Re: Knock Board Delete CEL on all the time no code flash
 
Why would you remove the knock board from the ECU ?

AceViolent Apr 27, 2025 11:02 AM

Re: Knock Board Delete CEL on all the time no code flash
 

Originally Posted by JRCivic1 (Post 52958425)
Why would you remove the knock board from the ECU ?

A previous owner swapped my cars engine from the stock H23A1 to an F22B, which has no knock sensor. I'm not comfortable with drilling and tapping a hole for a sensor, but I am comfortable with digital electronic stuff, since it's one of the classes I had to take for my industrial electricity certification and degree program. I found a couple tutorials, seemed easy enough. But I can"t find a lot of info on the design of the P14 ECU's to do more detailed work.

I also have a functional spare P14.


All times are GMT -8. The time now is 11:59 PM.


© 2026 MH Sub I, LLC dba Internet Brands