Idle issues after injector install.

[Spec B]

I plan on disabling closed loop in the idle range only - that should allow me to richen up to idle mixture to something that eliminates the surging idle issue. Worried about the long term effects of running 12:1 AFR at idle.

[Spec B]

Solution found.

 

My theory is that the bouncing idle was a result of the rapid closed loop afr adjustments being made by the ecu at idle. As the ecu tried to quickly react to the afr swings, and because of the size of the injectors, it resulted in a vigorous swing from rich to lean. The injectors are too large and running at too low an idc to make the appropriate small fueling adjustment required to get a nice smooth idle.

 

What i did was run in open loop (no afr corrections) and targeted 14.6 instead of 14.7 afr during idle. Since the ecu is not trying to make fuel trim adjustments in open loop at idle, the idle is as smooth as stock now without having to run it rich. Great thing about it is that it will continue to make adjustments everywhere else on the closed loop range, just not at anything below 1,000 rpm.

 

How to here: http://www.romraider.com/forum/viewtopic.php?f=33&t=7897

[joeleodee]

Awesome! I shall employ this method. Perhaps I'll switch my latencies back so it stops surging at cruising in low load. The beauty of my tuning setup is that I'm still using the v1 ap and I can build base maps through romraider.

[Spec B]

You should definitely try...takes 2 seconds on romraider. Only thing you should make sure of before you try it, is that your idle trims are really good (less than 2% adjustment). Remember the ecu will not try to adjust afr at idle after you do this. So your maf scale at idle needs to be really close.

 

Good luck!