I am curious about some operation on the aftermarket EFI systems. I have never run one or even worked on any aftermarket EFI systems as I have only worked with Mopar OEM EFI units up to 2011 when I retired. From what I figure the Mopar performance PCM controllers can only give performance boost at wide open throttle since all OEM controllers go in open loop at WOT as far as I know. So if you bought a Mopar performance PCM if can give more power at WOT but in normal drive modes it still has to meet emission standards as far as I know so it has to shoot for the perfect air/fuel ratio of about 14 to 1 which there is a word for it that I know I cant spell correct right now. That I know of OEM controllers in most modes are closed loop where the 02 feedback is used to control air/fuel for the best ratio to meet emission standards and make decent but not the most power. Most OEM will be in closed loop by the time the eng is about 120 degrees or even sooner. At WOT the controller has a program for the eng it has in it to give so much fuel in reference to MAP , ECT , RPM , TPS and any other sensor that it may use in the air/fuel ratio as it will ignor the 02 input at WOT.

My question is with the aftermarket controllers can you put it in open loop anytime you want to run off the program you have in it ? Like at the track when you come up on the converter will it be in an open loop program you have in it when you launch before you are at full throttle ? And does it learn at all in an open loop program you put in it ? The Mopar system I worked with of course will instantly learn in closed loop by first short term if a air/fuel ratio is changed for any reason and then if it stays that way long enough then by long term to drive the short term back to zero and then fine tuned by the 02.

So I am curious on the aftermarket performance EFI units if you can run it on a program anytime you want that you have in it thats an open loop type program and from what I have heard most aftermarket EFI units shoot for about 12 to 1 ratio for the most power ? Also will the aftermarket EFI units still adjust any by the 02 in an open loop you have in it at all or stick to the full program in it at that time ? I dont mean to go off track but I figure this may help the OP with his question about EFI some anyway and can help me or any of us that may use an aftermarket EFI unit sometime. Thanks , Ron