Do these O2 sensor graphs look ok?

[mechanic]

you reset the pcm give it time for the fuel trims to adjust

If nothing was changed, they will adjust back to the current engine running conditions, which will likely be exactly the same as before.

 

[07GTS]

That’s not how fuel trims work. LTFT adjusts to engine conditions every few minutes. Other than initial emissions programming the factory has nothing to do with it. Nothing is dialed in.

don't understand what ur meaning as i say factory isn't dialled in and u say trims don't work that way nothing is dialled in ? i know how fuel trims work base fueling is set in stone so STFT and LTFT operate together to keep CL fueling at stoich within there airflow boundarys, i had my engine dialled in so close all year round i could stay in constant open loop fueling with minimal error

 

[mechanic]

i had my engine dialled in so close

Could you be more specific about what you mean by ‘dialled in?’

 

[07GTS]

Could you be more specific about what you mean by ‘dialled in?’

i adjusted the VE table since im SD tuned, transient fuel tables, injector data offsets and other fuel multiplier tables so throughout the year my fueling stays within a small error percentage under any situation without the use of the 02's feedback

 

[mechanic]

i adjusted the VE table

So you’ve reduced the size of the window of tolerance for each cell in the fuel map. How is this going to benefit you?

if anything you’ve made your engine less capable of dealing with outlier conditions. Are you sure you haven’t dumbed-down your ECU without realising it.

Maybe I still don’t get it? I’m not sure.
Can you give me a specific example of what I’ve done? (Not in programming language, but real-world terms).

 

[07GTS]

So you’ve reduced the size of the window of tolerance for each cell in the fuel map. How is this going to benefit you?

if anything you’ve made your engine less capable of dealing with outlier conditions. Are you sure you haven’t dumbed-down your ECU without realising it.

Maybe I still don’t get it? I’m not sure.
Can you give me a specific example of what I’ve done? (Not in programming language, but real-world terms).

with my ecu there are a bit over 1000 cells (rpm v map) to adjust in the VE table so the closer u get that to spot on the better ( less error is less calculations the ecu has to consistently make from 02 feedback so the better the engine runs ) it also involves the transient fueling sorta like a pump shot on a carby setup, and all the multipliers based on various temps iat, ect, ivt, itt, as they all affect it under different conditions especially if ur modified

ecu is not dumbed down as it corrects more accurately for any outside temperature changes throughout the year so it is in a way smarter then it came out from the factory as its not relying on feedback for fueling it just knows now from my changes, only way i can simplify it is this think of it as a maths equation and the fuel trims are u having to write down all your working out to get to the answer (more fuel trims error is more working out) but if ur dialled in in the first place u just write down the answer so both do get to the same end product just one is alot less work

 

[shane_3800]

Before everyone gets too carried away. To actually know if the fuel is out or the sensors are faulty and over correcting you really need to use a gas anyliser to check lambda. If you haven't checked the actual lambda with an external sensor you have absolutely no idea if the readings the O2 sensors are giving the computer are correct.
you have to assume they're incorrect untill verfied otherwise you're just pissing up the creek.

 

[mechanic]

less calculations the ecu has to consistently make from 02 feedback so the better the engine runs

If you’re only after increased power output, you may as well toss the O2 sensor out the window. It’s not difficult to make power at the expense of fuel, emissions, longevity etc. Stoichiometry is of little importance in this instance.

What I don’t get is how you think your calculations are better than the O2 sensor and standard fuel maps. The O2 sensor adjusts for things you can’t possibly detect; worn compression rings and increased blow by, a partial blockage of an injector pintle, a minute gasket leak, small changes in oil viscosity etc.

Fuel maps contain millions of lines of data and thousands of hours of lab testing and analysis. There are fuel map adjustments made for every degree of coolant temperature, air temperature, engine load, fuel type, knock signal, battery voltage etc ... the list of parameters is almost endless.

You don’t type the way I’d expect an engineer to type, so I don’t think you understand that it’s not as simple as you describe.

Anyway, getting way off track.
O2 sensors are your friend. They help you diagnose engine faults and tell you faster than anything else when there’s a problem. You’ll never do a better job by manually overriding them.

 

[delcowizzid]

He is not overriding them he's tuning the actual ecu maps based off the o2 sensor feedback so the maps are more refined and the o2 are correcting less variation the closer you get it the better the economy as the ecu swings rich and lean over and over when in closed loop and watches the o2 feedback to add or remove fuel where needed.

 

[07GTS]

If you’re only after increased power output, you may as well toss the O2 sensor out the window. It’s not difficult to make power at the expense of fuel, emissions, longevity etc. Stoichiometry is of little importance in this instance.

What I don’t get is how you think your calculations are better than the O2 sensor and standard fuel maps. The O2 sensor adjusts for things you can’t possibly detect; worn compression rings and increased blow by, a partial blockage of an injector pintle, a minute gasket leak, small changes in oil viscosity etc.

Fuel maps contain millions of lines of data and thousands of hours of lab testing and analysis. There are fuel map adjustments made for every degree of coolant temperature, air temperature, engine load, fuel type, knock signal, battery voltage etc ... the list of parameters is almost endless.

You don’t type the way I’d expect an engineer to type, so I don’t think you understand that it’s not as simple as you describe.

Anyway, getting way off track.
O2 sensors are your friend. They help you diagnose engine faults and tell you faster than anything else when there’s a problem. You’ll never do a better job by manually overriding them.

ur thinking that factory is way more dialled in then they actually are they are not spot on, the fuel maps u think have millions of data is my VE table i have 1089 cells to adjust which is more then the engine will ever actually use (MAF sensor only has 66 cells to adjust), then i have multiplier tables for ECT, IAT, IVT, ITT and more then the injector data has all the offsets for delta pressure/flow, short pulse, min pulse, voltage/map offset, IAT offset, VOLTS offset, INJ tip temp offset its all there to adjust, fuel type flex setup and knock sensors all have there own settings u can adjust.

im not an engineer i just like to tune and go through as much as i can to see exactly what it adjusts and how it affects all other tables its the only way u gain knowledge about it, i have no issue with 02 sensors when they are running good but i also know that if u disconnect the 02's on a factory tune the engine will run like garbage because its not that dialled in it needs them where as after a proper tune like mine if i was using the 02's and disconnect them mine will still run the same no issues, even without the 02's i can still dial in stoich fueling and only use enrichment when power is needed so economy is better then factory (i have a wideband also for tuning), its why so many people do there own tuning as u can get it to run so much better then factory even using the 02's as factory has to suit hundreds of thousands of vehicles where as tuning can refine it to what your engine likes