Open Loop and Closed Loop Modes.

[Sassimac]

Hello All...

Is there a simple way to determine whether the ECU is operating in OL or CL modes..???

Thanks..!!

[mituc]

I think there is a PID for this but you can tell if the ECU switched from CL to OL by looking at the long therm FT, as they change to like -0.006401 or something (the VT logs list it as dead 0).
Also, normally the MAF g/s are above 190-200 when this happens.

[Sassimac]

Thanks for the tip.

I need to be able to determine at what point it switches in the logs, so I can fiddle with timing.

[Sassimac]

Hello All...

I have a Dashhawk, to help me keep track of things in real time. It can display Open Loop and Closed Loop via a small icon on the display. This indicator relates to the Fuel System according to the Dashhawk manual.

It shows:

"O" = Open Loop,
"C" = Closed Loop,
"L" = Open Loop due to engine load.

The third indicator has me a little baffled. My understanding is there are two modes. Closed Loop and Open Loop.

Comments..???

[Steve @ VersaTune]

OL can be triggered by APP or Load. There are configurable timers for how quickly the ECU transitions from CL to OL. During transition, values from both OL and CL tables are linear interpolated and weighted based on the timer progress.

[Sassimac]

OL can be triggered by APP or Load. There are configurable timers for how quickly the ECU transitions from CL to OL. During transition, values from both OL and CL tables are linear interpolated and weighted based on the timer progress.

Thank you for the information Steve.

From your explanation, I gather the ECU can report whether it has picked OL due to load or APP. This makes sense with what the Dashhawk reports.

Is it worthwhile changing the timers or transition points, considering my car is heavy and an auto?

[Steve @ VersaTune]

Personally I've never changed them on my car. The only reason to go OL is when the ECU processor speed and sensor sampling rate are inadequate to keep up with the rate of change of the engine conditions. If you are accelerating a lot faster than stock then you may want to start the transition sooner.

[manselainen]

So are you saying that your car is not faster than stock

[Steve @ VersaTune]

Yeah I run the GT3071R at 8 psi

If your OL and CL tables have the same values, it doesn't matter much which table it's hitting as long as the trims it's applying aren't throwing things off.