plx m300 datalog question

Hondata model coverage & ECU application questions.
dornon13
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plx m300 datalog question

Post by dornon13 »

I plan on hooking up my plx to my ecu so i can datalog...the question is i am running open loop 100% of the time so do i need to hook up the narrowband signal? also what pin does the wideband signal go to and do i need any resistors or anything for only installing that rather than the narrowband?
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Spunkster
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Post by Spunkster »

It would be a good idea to run in closed loop and use the narrow band output from the PLX to the ECU. When you want to datalog Wideband readings you just change the wire and connect the wideband output to the ecu. Details can be found at http://www.hondata.com/techwidebandtuning.html
dornon13
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Post by dornon13 »

can you elaborate on why i should run in closed loop instead of just keeping it open all the time..im just curious...either way i will not be running an o2 sensor for it to make corrections from so why would it matter...thanks for the help thus far
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Spunkster
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Post by Spunkster »

You get better fuel economy and emissions. Also using the PLX you can easily run in closed loop using the narrowband output.
dornon13
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Post by dornon13 »

how does it give better fuel economy without an o2 sensor? im not doubting i just like to learn as i go. i broke my o2 sensor and i dont want to buy another one but if i can run closed loop without the o2 and still run well ..oh wait i think i understand whats going on...the wideband o2 is giveing the ecu narrowband readings to correct from....i was thinking the narrowband was just to simulate so a CEL wouldnt show let me know if i am thinking correctly now..

also i am curious of what the lamda stuff is for.. is that the value the ecu will strive to get by going off o2 readings?
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Spunkster
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Post by Spunkster »

To run closed loop you need a sensor, but you said you have a PLX, so you can use that....just use the narrowband output to the ecu.
kesnut
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Post by kesnut »

i run with my plx in the car all the time...
i used the wide-band side to the ECU, and run open-loop all the time...
as my car is NA, on the dyno make the most power @ 13.6 AFR, so columns 7,8,9 and 10 are set to run @ that, the rest of the map i have set to 14.2
i can tell u it will be a lot of work, but after 2 months, i had the ecu remapped AFR wise by hand. i stay in open-loop to see if there are any spots that can be better, and it feels good drive in something i made... :)

it is also one of the best ways to learn the software, even now sometimes i will leave the laptop in the car and just datalogg
the hard part for me was setting value less the 1200 rpm...
(traffic driving)
dornon13
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Post by dornon13 »

yeah i am tuning on my own so far i am working on the out of boost portions and i have made a pretty good imporovement im pretty happy im just nervous to start on boost
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Spunkster
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Post by Spunkster »

Usign the PLX there is no reason not to run in closed loop. WHen you are done tuning switch it to closed loop and runt he narrow band input to the ecu. you can still see the Wideband readins on the PLX display and you can run in closed loop...you get the best of both worlds. I hav ebeen doing this on my turbo b18c5 for well over a year.
kesnut
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Post by kesnut »

one way or the other...
i can't say if it is better to do one or the other...
what i am thinking, is why u want tuh use the narrow side, if u want to run the car on closed loop, you can leave the ecu with the wideband side wired in and go into Closed Loop and set your target voltage.
EGHATCH
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Post by EGHATCH »

what wire should i connect to the o2 sensor input of the ecu from my plx? the gray one or the white one?

can i datalog lambda readings even if i run open loop?

i also run open loop all the time. isnt it that the wb sensor has a limited lifetime? so i only use it in tuning time..
you wont learn until you actually do it.
dornon13
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Post by dornon13 »

ok one last question...when running closed loop which signal do i run to the ecu? also do i need to have the plx conversion selected in my bin?
DaX
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Post by DaX »

The Honda ECU can only understand narrowband input [unless it's a P07 or other ECU designed for wideband input].

The benefits of running in closed loop are better gas mileage...as Spunkster said you still get to see true wideband values from the sensor on your PLX device, but from the box, the signal is emulated to a narrowband output so the ECU can understand it. Instead of you having to constanly watch your wideband meter, your ECU can make minute changes on the fly based on the narrowband info it's being fed, much quicker than you can, yielding better performance all around.

At least set your open loop threshold low so your car can at least run in closed loop at low RPM's.

Honda knew what they were doing when they designed the ECU.
dornon13
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Post by dornon13 »

so when using the narrowband signal and running closed loop do i need to have my plx conversion selected in my rom?
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Spunkster
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Post by Spunkster »

No, because you are using the narrowband output.
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