Someone familiar with the 65 ecm, $6E mask on an L98:

Without getting into the sordid details, I'm unable as of yet to do some datalogging but have a general question based on my observations with my car right now with the only mod on the chip being an increased injector constant to sort out an overall rich condition:

The car is more responsive overall in open loop. What does this say about the overall state of tune? I don't have too much knowledge about the differences between open and closed loop.
I do know that the 02 sensor doesn't kick in until closed loop, though.

What needs to be done in closed loop (in general, now, because I know that this all depends on a few good logging sessions one of these days!)? Is it possible the car is too lean now?

Any help would be appreciated.

 

During closed loop the ECM is trying to hold the AFR at a constant 14.7:1. This is the operating range of the cat-con. During open loop the AFR varies according to the engine coolant temperature and load. This is what makes it more responsive and in general a better running engine.

If the vehicle has a cat, which all US based street driven thirdgen f-body's are required to have, closed loop is really the only option. Running open loop will eventually wreak the cat-con.

RBob.

 

Do you mean when warming up, or all the time?.

A cold motor likes alot of fuel, and timing so you have fuel acting to slightly raise the compression ratio, and the engine seems more responsive, well that and the intake charge temps are low.

If you mean hot, and in open loop, then that would *tend* to indicate, it's a bit on the rich side. Once the cold engine timing decays out (rather quickly) open/closed loop doesn't change the timing (other then for knock, and that's just temp dependent).

Ultimately, for a mild engine, there shouldn't be any real change from closed to open loop. PE for all practical purposes isn't too drastically effected by closed/open loop.

 

Thanks to the both of you.
I do have reason to believe I'm a little rich and will try to increase the constant a bit more while I wait for the logging gods to shine on me and then maybe we can start doing this right!