O2 Feedback

[leprecaun96]

Maybe someone can clear a couple of things up for me..

Ive read when tuning the fuel maps with the PFC that the O2 feedback should be turned off. ok, but should it be turned back on after tuning is finished ?

Also, the o2 feedback loop, is it more economical to run with it on or off ?

[neo32]

i find with mine turned on it used to retart the ignition when u booted it and back teh fuel out

the tune on the car was farcked anyway what i have to loose i guess

turned it off again

and it would rev beter

not trying to lean it out etc

my engin prefers t run a little rich

[paulr33]

typically on when driving normally

it should be off when wideband tuning your car

in most scenarios you will get good economy with it on and a basic tune

if you have an aggressive tune and the tuner has spent lots of time on light cruise with a wideband sensor

you can get better economy with the 02 feedback off - you can also adjust the 02 feedback co-efficient

so its not just a fixed "stuck at 14.7" setting if that makes sense

[leprecaun96]

Ok, so when its on, are the maps setup on the pfc ignored?

Reason i ask, when on monitor, i dont see the ign timing that the map is set to for that specific rpm. ie the map is set to 28' ign for idle yet under monitor the timing is 15' ... this is with feedback on.

[blind_elk]

Ok, so when its on, are the maps setup on the pfc ignored?

Reason i ask, when on monitor, i dont see the ign timing that the map is set to for that specific rpm. ie the map is set to 28' ign for idle yet under monitor the timing is 15' ... this is with feedback on.

Closed Loop running doesn't affect the ignition timing, only the fuel delivery. You should notice the fuel ms varying (at cruise only!).

Closed Loop attempts to run the engine at 14.7 AFR by continually reading the O2 sensor output and adjusting the fuel delivery. Because it is reactive, rather than predictive, it continually overshoots 14.7, so the AFR actually cycles between "> 14.7" and "< 14.7" AFR.

[neo32]

are u shure it doesnt affect timing

mine goes realy dull when turned on

fells like the timings realy retarted

[neo32]

also when its on the maps arnt ignored just the cruse and idle maps i think it adjusts

[blind_elk]

are u shure it doesnt affect timing

yes, I'm sure

mine goes realy dull when turned on

fells like the timings realy retarted

you mean retarded ?

[leprecaun96]

For the government emissions test they have a low idle and a hight idle test (high idle being they hold the engine to approx 2750rpm).

My car is failing on high idle on carbon monoxide, whether feedback is on or off.

Anyone know if i took fuel out of the cells around that point will it bring the CO down?

Or do I have to put the cat back in (de-cat pipe fitted), in order to pass this damn test?