Pros and Cons of Open Loop Idle on E6

[MAC]

I have been chasing a closed loop idle problem. Closed loop idle works great except for a little stumble every ~5 seconds. It is related to AE but I am not sure if it is being caused by AE. Everything is idling along nicely and then I see AE go active for just a moment, there is a little stumble, and the process repeats.

I am weighing my options and thinking about open loop idle. When the truck starts it idles very happily and smoothly in open loop. This makes me think I should just figure out how to make it idle in open loop all the time and be done with it.

Is this logic flawed? What are the benefits of closed loop idle? Is the prevailing logic to use closed loop idle whenever possible? If so, why?

The truck has a very mild cam. CS-1014R by sealed power. 204/215@.050 with 112 LSA

[MAC]

Datalog attached for anyone who is interested.

[dave w]

Maybe try adjusting the vacuum parameters for AE to prevent AE from becoming active at idle.

dave w

[MAC]

Maybe try adjusting the vacuum parameters for AE to prevent AE from becoming active at idle.

dave w

I looked at that.

Title: MAP Difference to Enable AE at Idle
Location: 48AF

Set to 21.4 Kpa in my BIN. I found numerous examples in the datalog where the MAP difference is less than 2 Kpa and AE is still coming on. Time stamp 11:06.020 and 11:14.421 are two specific examples.

No sensor value seems to be changing. BLC is not changing. Even IAC present motor position is steady whenAE comes on.

It must be something else causing AE during idle.

Having trouble even finding things in the BIN to look at. Does anyone know what Lower Threshold for IAC AE Location: 5096 and Upper Threshold for IAC AE Location: 5097 are used for? Mine is set at 2% flow and 3.9% flow. What flow is this? Injectors?

No tips in the XDF.

[troutdog311]

A different vehicle but kinda same issue. I was having a hesitation after CL was active. Car is far from stock and did all the processes to try to over come the issue. I ended up going OL. After much tuning I got OL as close as I could get it and the car runs like never before. Throttle respond is much much more snappy with zero hesitation. I was told it would give me issues with outside temp changes but haven't as of yet. MPG dropped slightly but as little as I drive it it ok with me.

[MAC]

A different vehicle but kinda same issue. I was having a hesitation after CL was active. Car is far from stock and did all the processes to try to over come the issue. I ended up going OL. After much tuning I got OL as close as I could get it and the car runs like never before. Throttle respond is much much more snappy with zero hesitation. I was told it would give me issues with outside temp changes but haven't as of yet. MPG dropped slightly but as little as I drive it it ok with me.

Thanks troutdog. Are you running E6? What steps did you take to prevent open loop ldle?

[dave w]

Attached is a screen shot using the Parameter Finder feature of TunerPro. There are several AE parameters. Maybe MAP difference to Enable AE at Idle?

dave w

[MAC]

Attached is a screen shot using the Parameter Finder feature of TunerPro. There are several AE parameters. Maybe MAP difference to Enable AE at Idle?

dave w

Check out my post #4 above. My BIN is set to 21.4 Kpa. Data logs have a delta less than 2 when the AE comes on.

Also - love me some parameter finder!