Open loop, closed loop temperature?

2000tjguy said:
Understood but to me it would make sense to have the determined temperature set below the stock stat temperature of 195*.
I have driven many different vehicles in very cold conditions with the coolant temp making big temp swings as the thermostat opens and close which very well could be throwing it back and forth between open and closed loop or closed loop temp could be set lower than the thermostat temp to combat these conditions which could actually mean optimal operating temp is actually lower than the set 195*.
Or I could very well be wrong but I wanted to test it to see even though I doubt I would even be able to notice a difference.
Damn me for being a person who likes to tinker 😂
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Yep, no one here likes to tinker...

You have a collection of thermostats already and could have bought a cheap scan tool to provide you with OL information to find your answers.

Rather than tinker in any useful manner, you made a word spaghetti post and since have complained about the valid responses that have attempted to understand your intentions and remedy your ignorance.
 
MikeE024 said:
Yep, no one here likes to tinker...

You have a collection of thermostats already and could have bought a cheap scan tool to provide you with OL information to find your answers.

Rather than tinker in any useful manner, you made a word spaghetti post and since have complained about the valid responses that have attempted to understand your intentions and remedy your ignorance.
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Already told you I was going back to a 195* stat what else do you want from me? I mean I figured that would finally make you happy but I guess you just can’t please everyone.
The rest of the conversations have actually been somewhat constructive or atleast I thought they were… not sure where I have complained or been ignorant.
 
Wildman said:
I guess where I got confused is that the system goes from open to closed all the time depending on throttle & other factors. Or that is my understanding on how it works from watching my engine.

I'm sorry I haven't said you were doing anything wrong I'm just trying to understand. And if I could help.
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What I have seen ( not on my Jeep) certain conditions the engine can go back into open loop and use values stored in the pcm for fuel and timing. My experience is it usually happens at idle or wide open throttle. I don’t usually see it on OBD 2 vehicles but TJ’s are early OBD 2 vehicles so you may see this happen. I have not played with mine enough to know.
 
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NskLJ said:
Never heard off long term vs short term closed loop.
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I've read that the closed loop tables can be influenced by long-term fuel trims (which of course are adjusted by short-term fuel trims)...that all sounds good to me but I know next to nothing on how it all works.
 
Info from 2004 TJ , JTEC+ , PCM, 2006 has similar enable temp for primary O2 sensors.

04tj02senstemp.jpg
 
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MikeE024 said:
I've read that the closed loop tables can be influenced by long-term fuel trims (which of course are adjusted by short-term fuel trims)...that all sounds good to me but I know next to nothing on how it all works.
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I think you are referring to adaptive learning where the pcm learns the needed parameters for certain operating conditions.
 
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Just found these:
 

Attachments

  • NGC and GPEC Speed Density Fuel Systems.pdf
    2.5 MB · Views: 40
  • Next Generation Engine Management Part 1.pdf
    6 MB · Views: 40
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TEZZA said:
Just found this:
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I have that one (Part I), along with Part II, and Part III in hard copy. I found them on eBay. I'm too lazy to scan them, so having them in pdf is awesome. Now, we just need to find Parts II and III in pdf form!
 
Painfultruth said:
I put all the PCM documentation JTEC, NGC on the manuals thread long ago, go through it and you will find them.
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Well, heck. I wrongfully assumed that all the manuals had been updated to the first post. I just found your post with a Google search. Awesome - thanks for putting those in there! Now I have to page through all twelve pages to see what other hidden gems I've missed...
 
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