I was wondering if there was any way (or benefit) of running wideband o2 sensors into the stock PCM so it can run the O2s in WOT.

Wouldnt that be the best way to get a steady AFR at WOT. Can this be done on a stock adjusted PCM?

Im just curious about this.

Thanks,
Stu

 

Nope none at all. The ECM doesn't trim fuel in WOT. In other words the o2 sensors don't give ANY feedback while in WOT, they are only used in normal driving/part throttle operation, like whenever you aren't into the pedal. There wouldn't be any benefit on using them for part throttle either because that's all our o2 sensor's are designed to do and the stock sensor's work perfect at doing just that.

 

well you could do it (I think). The pcm can be programed to run in closed loop even at WOT. I am not sure how well this would work since the pcm is trying to hit 14.7:1 air fuel mixture and this is not what would be optimal. You maybe able to program it to hit a different air/fuel mixture but I am not sure.

 

no, period.

a wideband uses 0-5v, 0 being rich, 5 being lean.

a narrowband uses 0-1 volt. 0 being lean, 1 being rich.

the voltages are way different, and read opposite.

there are however narrowband simulators, which is what you would use when you dynotune your car at a shop. The stick in a wideband o2, which has two outputs, an analog wideband output that goes to the dyno software, and a simulated narrowband that goes to your pcm so your pcm. So if you were to buy a wideband o2 gauge, make sure you get narrowband simulation.

"The ECM doesn't trim fuel in WOT" - sort of but no

The pcm takes the last l-term trim number and uses that when in WOT. Only the s-terms are locked during WOT. So if your o2's are going out and reading a lean condition, your s terms jump to 200, and it sends your l terms to 160 within 30 seconds or so, cause you to run really rich. so when you floor it, it will be dumping in a HUGE amount of gas, even though your s-terms temporarily go to 128 due to WOT, because your l-term is still at 160.

 

Well NO is a bit harsh. If we know what a widebands output is(5-0v) and what the PCM o2 input is(0-1v), then some circuitry is what would be needed. I am not an electrical engineer so I don't know what that would involve but, it is definitely possible. The problem may could arise if there is a small number of bits available for the o2 input(very likely) then there could be a significant lose in precision going from a 5 volt range to a 1 volt range.

However I still think the main concern would be programming the PCM to hit any other air/fuel ratio other than 14.7:1. I do not know if this would be possible.

So if anyone knows how many bits the PCM uses for the o2 reading that would useful info. Also if an EE would like to chime in on how complex the conversion would be, that could also shed some light for you.

 

It wouldn't be worth your effort. The wideband output is linear, and the narrowband is not. Figuring out how to simulate narrowband from the wideband has already been done with almost every wideband kit.

 

with a converter like the lm1 you can feed the wideband data into the pcm and then tune accordingly...

The reality is that the PCM is not programmed to use LTrims in WOT as it puts itself in open loop... If some of you Assembly gurus out there can develop a software for this you would be home rich.

 

if you want one that bad, just replace you stock computer and harness with one from FAST engineering. They run WideBand O2s on there setups. In my opion its not worth it. Look how many people are running the stock computer and no wideband.