Help with air fuel controller

[hvychvy81]

Hey guys,
I'm trying to build my own air fuel controller. I know they make them, but I dont want to spend alot of money on some pretty LCD display.

I built one a while back that was pretty simple. It consisted of two 10k potentiometers that ran in line with the MAP sensor. This was used to change what load the computer read on the engine, thus changing the A/F ratio. I do not know if it also caused the timing to retard.

My problem with it was that is was basically one setting with a fine tune. What I want to do is use multiple potentiometers to adjust the A/F at a given rpm. What could use to read the rpm that would also change to the pot that was set for that RPM.

i apologize if I did not describe very well what I'm doing, if anyone has any advice please let me know... thanks in advance

 

[MikeHalloran]

You could feed a crankshaft pulse to a microntroller that would compute the RPM, read the position of one of a multiplexed array of pots, and use that information to adjust a programmable pot or select a combination of resistors to switch into the MAP sensor wiring to approximate the pot setting.

It would probably be easier to just hack the microcontroller that's in the ECM already and adjust the ECM's fuel map directly instead of lying to it.





Mike Halloran
Pembroke Pines, FL, USA