Open loop vs close loop and when it turns on

[Robotech]

I'm researching open loop vs closed loop. Right now the car is "locked in open loop" but it bucks while driving down the road as the AFR bounces generally from 14.7 to 13.1 and then back again within a few seconds. I was reading that if I disabled the "locked in open loop" then closed loop from the ECU takes over and it will smooth out those bucks.

I have a few questions, the primary question being: When does the ECU switch from closed loop to open loop? Is it based on load factor or is it based on a certain RPM? I can't find anything in ECMLink that tells me when to set a preset for when it switches.

The second question is that this car is a 10 second drag car, but i drive it on the roads sometimes and want to eliminate the bucking. When I'm dragging it at the track do I have to recheck "locked in open loop"?

Third: This is a E85 car, can the ECU manage closed loop for E85?

Thanks
David

 

[91talonts1]

The tab to adjust the open loop switchover is called "openloopthreshold" in direct access. It is based on load factor indexed by rpm in two ways, and by TPS position.

You can leave closed loop enabled even at the track. Locking it in open is useful for things like not having an o2 sensor.

The car will run in closed loop on e85 just like gas.

 

[tay97gst]

https://www.ecmtuning.com/wiki/fueltrimupdatepoints

This will answer most of your questions regarding closed and open loop operation.

 

[Robotech]

The tab to adjust the open loop switchover is called "openloopthreshold" in direct access. It is based on load factor indexed by rpm in two ways, and by TPS position.

What do you have your rates set at? Is it wise to change the immediate OL values for either the TPS or the loadfactor? Mine are completely stock. Personally though I am thinking that I'd like the open loop to turn on sooner than the loadfactor of +1 up to 3500 rpm. Though I have a big turbo that doesn't spool until 5000 rpm, so maybe it won't matter to me as much.

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Thank you for your help!!

 

[91talonts1]

The stock open loop thresholds have always worked fine for me. I have raised them before like the ecmlink wiki advises when dialing in cruise, but then I always set it back to the defaults.

 

[kmetiuk]

What do you have your rates set at? Is it wise to change the immediate OL values for either the TPS or the loadfactor? Mine are completely stock. Personally though I am thinking that I'd like the open loop to turn on sooner than the loadfactor of +1 up to 3500 rpm. Though I have a big turbo that doesn't spool until 5000 rpm, so maybe it won't matter to me as much.

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Thank you for your help!!

Just leave them at the defaults. The thresholds are fine as is. Uncheck the "locked in open loop" tho....no need to run that.

 

[Robotech]

Just leave them at the defaults. The thresholds are fine as is. Uncheck the "locked in open loop" tho....no need to run that.

Thank you I'll give it a try when the rain stops in a few days... .

 

[kmetiuk]

Thank you I'll give it a try when the rain stops in a few days... .

Can you post a log or a saved setting or something for us to look through?

In your first post I can see a lot of bold menu items in the Direct Access.

Some of which don't need messing with very much or at all. I'd be curious to see the TPStipin, Loadscale, Airflowsmotthing, Coolnatempfuel, and CrankingFUelAdj.

Also if you could update your dsm profile for this car it would help drill down on why it may be bucking.