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Thread: Open loop w/wideband???

  1. #1
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    Open loop w/wideband???

    Okay, reading thru all the posts about widebands I hear people say they are tuning/running in open loop 24/7. How is this possible? The computer should go into closed loop when engine reaches operating temp. The pcm doesn't run in open loop unless cold or WOT. Can someone give a good explanation of why running a wideband as the nb would cause the pcm to be in open loop
    2000 GTP- S2X, diamond forged 9.5:1, balanced, Lucas 42.5#, GenV w/N*, stage 3 heads, custom PCM, ZZP SS IC, TOGS, MPS 3.0, Intensified 3.69's tranny - low 12's!!!!

  2. #2
    Running a wideband as a narrowband has nothing to do with open loop.

    To get your PCM to stay in open loop, just raise the close loop activation ECT to its max value, ~256 something. Unless your engine starts melting, it wont get hot enough to activate close loop.
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  3. #3
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    Quote Originally Posted by RoninsDenali
    Running a wideband as a narrowband has nothing to do with open loop.

    To get your PCM to stay in open loop, just raise the close loop activation ECT to its max value, ~256 something. Unless your engine starts melting, it wont get hot enough to activate close loop.
    Thank ya' sir. But what are the advantages of running open loop even during normal driving? Wouldn't you want the pcm to control the fueling, timing, etc. off what it thinks it needs instead of what we tune into it? Or are you talking about speed density open loop or something?
    I'm staying with my maf. I don't think I'm good enough at tuning to run sd.
    2000 GTP- S2X, diamond forged 9.5:1, balanced, Lucas 42.5#, GenV w/N*, stage 3 heads, custom PCM, ZZP SS IC, TOGS, MPS 3.0, Intensified 3.69's tranny - low 12's!!!!

  4. #4
    Señor Tuner MeentSS02's Avatar
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    Quote Originally Posted by 00GTP
    Thank ya' sir. But what are the advantages of running open loop even during normal driving? Wouldn't you want the pcm to control the fueling, timing, etc. off what it thinks it needs instead of what we tune into it? Or are you talking about speed density open loop or something?
    I'm staying with my maf. I don't think I'm good enough at tuning to run sd.
    With the headers in my car, the narrowband O2 sensors went south in a hurry on me. They just weren't reliable anymore. Since that is how the PCM gets its feedback (i.e. closed loop operation), it didn't make sense to even take this feedback into consideration. Now it stays open loop 24/7.

    An SD tune isn't hard at all...HPT pretty much does all the legwork for you. You just have to make sure you can trust your wideband's readings, and make sure the wideband output and the EIO input are in agreement. The rest is driving and copy/paste special.
    2008 Viper - now with HPToona - 1/4 Mile Shenanigans Here
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  5. #5
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    Yeah Steve, I don't trust the nb either, especially after popping 2 pistons.
    So basically, after proper tuning and entering in the correct parameters, I could rely on open loop since the pcm would be reading what is "correct"?
    2000 GTP- S2X, diamond forged 9.5:1, balanced, Lucas 42.5#, GenV w/N*, stage 3 heads, custom PCM, ZZP SS IC, TOGS, MPS 3.0, Intensified 3.69's tranny - low 12's!!!!

  6. #6
    Señor Tuner MeentSS02's Avatar
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    Quote Originally Posted by 00GTP
    Yeah Steve, I don't trust the nb either, especially after popping 2 pistons.
    So basically, after proper tuning and entering in the correct parameters, I could rely on open loop since the pcm would be reading what is "correct"?
    Although I'm not familiar with your type of operating system on your car, that is the basic idea. I tell my car what to do, and it finally doesn't argue with me about it
    2008 Viper - now with HPToona - 1/4 Mile Shenanigans Here
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