well i got my car tuned today with the vafc hack. when we installed the wideband o2 and did run the car in open loop which was with no o2 hooked up the car ran great no hessation or jerkynes at all. well then i put the o2 back in and ran the car closed loop there is all the hessation and jerkynes back and dosnt pull as hard eather. so is there some kinda conflict with running an o2 on the hack? well i am going to remove the o2 and go into open loop and run it that way. has this happened to any one else? any input would be great.

 

i tuned the car. it ran perfect with perfect A:F. O2 sensor put back in and runs crappy. Would like to hear an answer. Anyone know enough about the VAFC hack and how the car runs with the stock sensor? Does the ECU even allow closed loop with the AFC?

thanks

 

I have never heard of anyone not running an o2 on the hack including myself. I am probably wrong but doesnt the ecu go into a safe mode and dump extra fuel when the o2 is unplugged? Since it was tuned without the o2 unplugged maybe its getting lean when it goes into open loop with it plugged in. I think you would not have had any problems if you would have been able to wideband tune it with the o2 hooked up. I would weld in another o2 bung and try again.