AFR question

[mrlogix]

the 1125R comes stock with narrow band O2 sensors. Is their a way to adapt wideband O2's that the ecm can use them or does it take a third party device to get the info into a usable format for the ecm? Or is the ecm programs to stupid to use the widebands in anyway?

[Matteson]

I believe the ecm uses the voltage reading based on parameters already set. So if the voltage reading is wider it would utilize it. I think in spy there is a way to adjust the parameters to the bandwidth of the wb's so it can utilize the wb's info. I could be way off.

[d_adams]

I think it's pins 31 and 33 for wideband data logging, but I'd look on the ecmspy site for verification. To my knowledge, it does not work with the ecm as far as plugging them in and having it work. I had originally planned on doing exactly that with the plx setup, but never got a chance to really dig into it. I did ask, the answer I got was it would work for logging only, if it worked at all. That answer was direct from an engineer at ebr.

[lawdog]

I think it is possible but you would have to reprogram the EEPROM due to different max,min,and midpoint voltages. I don't think it would be worth the effort personally. What are you trying to do exactly?

[mrlogix]

after reading about the difference of capability of narrow band vs wide band, it would allow the ecm a finer control of the AFR. With the engine mods I'm planning it would be helpful for the ecm to have this enhanced control capability. I understand the changing the range and mean of the WB input conversion detail. This is referred to as scaling with parameters in the industrial control world. Just wasn't sure that the tables would allow a change of these scaling parameters via TunePro RT and allow me to flash the eeprom.

[lawdog]

Ok gotcha. Well I don't know if it can be done via Tuner Pro but I know I can do it just changing the raw hex data.

But I don't think it will do what you think it will. The ECM can only compute so fast. O2 rich remove fuel, 02 lean add fuel. Just back and forth like a switch. No scaling so to speak. It is either above or below the midpoint and the ECM will either add or subtract fuel. So whatever the midpoint voltage is set at is what corresponding afr you will get. It won't scale the percentage of fuel to add or subtract based on how close it is hitting the target afr. Plus in the real world there is no need to be that accurate. The AFR bounces all over the place based on many different factors.

The only time people run the wideband with 02 learn enabled is so they can datalog and have the add-on module provide data to the ECM to allow global correction. Otherwise the wideband direct to the ECM will function the same as a narrowband with no real benefit.

I would run a wideband to datalog to tighten up your fuel maps so there is less swings between different tps/rpm settings. Only you can change the individual cells. The ECM will follow whatever you tell it to for fuel and adjust from there. Then either let it feed data to the ECM and leave it on or pull it and sell once you are happy and hitting your target AFRs in each cell.

[mrlogix]

that's what I needed to know. Thanks Lawdog. +1 from me.

P.S. nice handle, I take it you are in law enforcement. I train a lot of local LE here in SW Ohio in CQB and Pistol Tactics. I'm a certified instructor with the NRA and RangeMaster (Tom Givens).