Well,

Based on the translated open loop throttle tables from my map, and the info provided by you helpfull folks, I think I have enough info to try a few things. I'm going to start by revising the timing in the 90-100 load area and modifying the open loop throttle table to try and drop out of closed loop at 38% TP, that should keep the fueling richer in the problem area and still maintain a reasonable area for closed loop cruize. I'll post up the modifications and results either this evening or tomorrow.

Thanks for the help fellas!

 

I made the following observations via normal OBDII logging:

When the throttle is closed, the logger reads 0%
If you barely tap the throttle, the reading goes up... It seem to be well zeroed
Max throttle yields from 99.6 - 100%
The resolution seems to be 0.4%.... that equates to about 251 points from 0-100%
Cruizing on flat land(hard to find in WV) at 75MPH is about 20%
I pick up quite a bit of acceleration at 30%... well enough to pass on the interstate.
Open loop still seems to come in just under 30%

 

How are you determining when the car drops out of closed loop mode and into open loop?

My observations are based on evoscan logs and the O2 feedback value. It seems that the value goes static to 100 (no correction for o2 sensor feedback) when the car is open loop. The observations I made seem to jive with the openloop throttle tables in my rom in that at low rpm it drops to open loop at about 60% throttle rather than 30:

RPM TPS
500 60%
1000 60%
1500 60%
2000 60%
2500 60%
3000 60%
3500 60%
4000 50%
4500 36%
5000 36%
5500 36%
6000 35.6%
6500 35%
7000 35%
7500 34%

I had thought it was a situation that required both the open loop load value and the throttle position value to be met, but it could be an either or case.....

 

OBD logger tells you if you are open or closed loop.

 

Interesting, my ECU+ should be showing up this week so i will check that out.

I do find it interesting though that these tables exist and translate to exactly the behaviour I was seeing........

 

I think that you may be right in that it is an either/or case. My logs have shown open loop at less than 60%, but only with comparatively high airflow. Lower airflow numbers and TPS > 60 have also = open loop.

l8r)

 

I either look for when the long term fuel trim goes to 0% or when the O2 sensor voltage becomes relativly steady. I'll do some logging in the next day or so and post the log graphs.

Are the units in ECUFlash shown as percentages? Is there a chance that they are not percentages? I find it hard to believe that you have to go to 60% throttle to go into open loop mode.

 

As promised.

I was getting a crappy data rate.... about one set of data every half second. I think you can see where it goes open loop though.