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Thread: Talk about your all-time bonehead moves

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Posts: 81-90 of 113
2012-12-12 01:23:37
#81
i'm going to let someone else take over from here, i get irritated and have a hard time putting my thoughts into words.

i've noticed on more then one occasion that the info you post isn't exactly correct, one example is the downpipe gasket.. so your join date tells me your new here and then you posting incorrect shit also tells me that.

i'm just as guilty of posting incorrect shit sometimes but i usually will admit that im either not sure or could be wrong, then when proven wrong i own up to it. however that doesn't happen as much these days as it did when i was new.
2012-12-12 04:38:32
#82
Originally Posted by lynchfourtwenty
a bad or no o2 sensor will fuck with afr's a bit, i know this for a fact.


Bad O2 will mess with the AFR's while your in closed loop, in open loop your fuel map will determine AFR's. I've been running both of my turbo cars without an O2 sensor. P11 is NA right now with no front O2, it also had no front O2 when I was NA VE. No difference in drivability.

Originally Posted by Storm88000
But on OBD2 it will throw a check engine light


That is correct.

Originally Posted by JimmyRustles
Realize that when in open loop those afr's are determined by the values in your ecu, I'm not referring to an aftermarket ecu with unknown parameters. On a car where the maf/injectors have not been modified unplugging the O2 will not affect the drivability at all since the engine won't be reading input from the 02 once in open loop

Idle is considered closed loop and mainly for emmissions.


All but last bit is correct. Idle can be both closed and open loop. I personally watch it jump in and out on my OBD2 P11 with a scangauge.

Originally Posted by JimmyRustles

See my edit...idle and constant speed sections are closed loop. WOT or partial are open. This is basic facts.

Lol at you equaling join date to experience. I've been a member of various car forums since 2001.


You are correct, not sure what Josh is smoking today.
2012-12-12 05:11:12
#83
maybe im confusing open loop with closed loop?

my point is under cruise if you have numbers in the fuel map in the 190's or close to it, which is for using the o2 sensor feed back, if not you use numbers from 0 up.. unless im mistaken? so while idling or cruising around in that area your using the o2 feedback part of the map.. correct?

i too have been o2 sensor-less in my se-r for 3 years, and if you tune it to run the way you want without it, its fine. but say you load up a stock bin (even on a stock car) there will be afr differences with an without the sensor..

i know its best if your not going to use a sensor to actually just turn it off and tune with out it.
Last edited by lynchfourtwenty on 2012-12-12 at 05-22-07.
2012-12-12 05:48:35
#84
Originally Posted by lynchfourtwenty
maybe im confusing open loop with closed loop?


Open loop means ECU is not listening to the O2 sensor feedback and is using the values in each cell.

Closed loop means it first uses the value in the cell to get a base AFR. Which it then uses O2 sensor feedback to add or subtract fuel to keep it around 14.7afr.

Originally Posted by lynchfourtwenty

my point is under cruise if you have numbers in the fuel map in the 190's or close to it, which is for using the o2 sensor feed back, if not you use numbers from 0 up.. unless im mistaken? so while idling or cruising around in that area your using the o2 feedback part of the map.. correct?


If a fuel cell is above value 128, O2 sensor will be used in that cell if the O2 sensor flag is enabled. If the O2 sensor flag is disabled, or O2 sensor is missing it will take the cell value minus it from 192 and get the fuel amount to use.

So say you have a cell that is 200, we already know that 192 = 0, thus 200 = 8. But if we go in the reverse direction and have 180. This means the cell is actually -12. -12 is less fuel then 0.

This is why, even though I run without an O2 sensor, I still keep the feedback cells, it lets me lean out the mixture. If you don't use feedback cells the lowest value you can use is 0, no negatives allowed. Thus you would have to lean out your K value or injector scaling.


Originally Posted by lynchfourtwenty

i too have been o2 sensor-less in my se-r for 3 years, and if you tune it to run the way you want without it, its fine. but say you load up a stock bin (even on a stock car) there will be afr differences with an without the sensor..


Actually every time you reset your ECU, the ECU goes back to using the stock map as a base, but then as you drive it it gathers O2 sensor readings for those cells and adds or removes fuel to keep it around 14.7. This is call your short term fuel trim.

Now there is a long term fuel trim too, that will take your average afrs for that cell since the last time you reset your ECU and will make adjustments based on that. This is why most small mods you don't see gains in gas mileage until way later. ECU self tunes itself to the new mod and reduces/adds fuel.

I personally don't like this, I want my car to run top notch and be fine tuned from the get go. This is why I have been running without an o2 sensor.


Originally Posted by lynchfourtwenty

i know its best if your not going to use a sensor to actually just turn it off and tune with out it.


That is correct, if you have no O2 or have a faulty O2 disable the O2 sensor flag.
2012-12-12 05:50:48
#85
ok we're on the same page then. as i said i was having difficulty putting my thoughts into words. thanks V.
2012-12-12 06:22:57
#86
Originally Posted by lynchfourtwenty
maybe im confusing open loop with closed loop?

my point is under cruise if you have numbers in the fuel map in the 190's or close to it, which is for using the o2 sensor feed back, if not you use numbers from 0 up.. unless im mistaken? so while idling or cruising around in that area your using the o2 feedback part of the map.. correct?

i too have been o2 sensor-less in my se-r for 3 years, and if you tune it to run the way you want without it, its fine. but say you load up a stock bin (even on a stock car) there will be afr differences with an without the sensor..

i know its best if your not going to use a sensor to actually just turn it off and tune with out it.


I'm not that worried about it. Seems as if your jimmies rustle easily (pun intended)
These cars are designed to be able to be driven without an O2 hooked up. Will it affect your cruising mpg's? Slightly. Will it affect low throttle emmissions? Yes.

And please don't equate join date to knowledge. I built my first setup in '01 and B series cars are all I've ever owned with the exception of my RL. I really like the comadre of this forum compared to others that I've been a part of and that's what drew me to finally make an account.

@ Vadim- thanks for clearing everything up for me.
2012-12-12 06:30:03
#87
Originally Posted by JimmyRustles
Originally Posted by lynchfourtwenty
maybe im confusing open loop with closed loop?

my point is under cruise if you have numbers in the fuel map in the 190's or close to it, which is for using the o2 sensor feed back, if not you use numbers from 0 up.. unless im mistaken? so while idling or cruising around in that area your using the o2 feedback part of the map.. correct?

i too have been o2 sensor-less in my se-r for 3 years, and if you tune it to run the way you want without it, its fine. but say you load up a stock bin (even on a stock car) there will be afr differences with an without the sensor..

i know its best if your not going to use a sensor to actually just turn it off and tune with out it.


I'm not that worried about it. Seems as if your jimmies rustle easily (pun intended)
These cars are designed to be able to be driven without an O2 hooked up. Will it affect your cruising mpg's? Slightly. Will it affect low throttle emmissions? Yes.

And please don't equate join date to knowledge. I built my first setup in '01 and B series cars are all I've ever owned with the exception of my RL. I really like the comadre of this forum compared to others that I've been a part of and that's what drew me to finally make an account.

@ Vadim- thanks for clearing everything up for me.




Then we're in agreement

I had alot of stuff going on earlier that I wont bore you with, I try not to get too irritated and you'll find I'm a pretty chill dude, and I try to help out around here as much as I can. I also know join dates don't mean much but you gotta see where I'm coming from here? We get a alot of traffic and sometimes folks can be counter-productive
2012-12-12 06:32:29
#88
I know lol. I've just found that 90 percent of the serious hardcore build guys I've met never even go on forums. Where else are they supposed to find Craigslist deals?
2012-12-12 07:05:22
#89
Originally Posted by JimmyRustles
Once at operating temps the ecu goes into open loop and operates the engine on the ecm values.
O2 sensors are used to maintain stoich conditions until at full temp which helps with fuel economy. It will not cripple an engine.


You got that backward. A cold engine runs in open loop, ignoring the o2, and follows the cold engine enrichment trim and timing. At a predetermine engine temperature, say above 140F, it will then go into close loop and takes in the feedback from the o2. There's a reason why the o2 has a heater circuit.

I also don't run the the factory narrow band 02, but inorder for it too work well (good mileage, smooth running, good idle) it require a programable ecu and wideband for tuning. Not recommended if you have a stock ecu.
Last edited by KillerKrossover on 2012-12-12 at 07-24-08.
2012-12-12 07:23:09
#90
Originally Posted by 5speed
Originally Posted by JimmyRustles
Once at operating temps the ecu goes into open loop and operates the engine on the ecm values.
O2 sensors are used to maintain stoich conditions until at full temp which helps with fuel economy. It will not cripple an engine.


You got that backward. A cold engine runs in open loop, ignoring the o2, and follows the cold engine enrichment trim and timing. At a predetermine engine temperature, say above 140F, it will then goe in close loop and takes in the feedback from the o2. There's a reason why the o2 has a heater circuit.


Automotive oxygen sensors, colloquially known as O2 sensors, make modern electronic fuel injection and emission control possible. They help determine, in real time, if the air–fuel ratio of a combustion engine is rich or lean. Since oxygen sensors are located in the exhaust stream, they do not directly measure the air or the fuel entering the engine. But when information from oxygen sensors is coupled with information from other sources, it can be used to indirectly determine the air-fuel ratio. Closed loop feedback-controlled fuel injection varies the fuel injector output according to real-time sensor data rather than operating with a predetermined (open-loop) fuel map. In addition to enabling electronic fuel injection to work efficiently, this emissions control technique can reduce the amounts of both unburnt fuel and oxides of nitrogen entering the atmosphere. Unburnt fuel is pollution in the form of air-borne hydrocarbons, while oxides of nitrogen (NOx gases) are a result of combustion chamber temperatures exceeding 1,300 kelvin due to excess air in the fuel mixture and contribute to smog and acid rain. Volvo was the first automobile manufacturer to employ this technology in the late 1970s, along with the three-way catalyst used in the catalytic converter.


Oxygen sensor - Wikipedia, the free encyclopedia
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