Hondata

Can I check whether it is safe to switch directly to close loop after car is road tuned? My tuner has tuned the car but left it in open loop. I would like to switch it to close loop as I heard running in open loop is not recommended in the long run when the engine and environmental factors might change. E.g change of air intake from fat tummy to straight piping etc.

Is it safe to just switch to close loop using S300? Will I encounter problem like O2 sensor not in good condition and cause AIR/FUEL ratio to be too lean or rich etc? If so, how can i check whether my O2 sensor is in good condition? I am driving a 1998 OBD2 EK4 (running hondata S300)

log the o2. it should swing around 0.5v.

how does your car idle in closed loop?

Hi johnny, do you mean add a O2 sensor under "Display" and monitor whether it is constantly 0.5V?

Anyway, I just uncheck the 'CLOSED LOOP OPERATION' option under PARAMETER->CLOSED LOOP button and add a O2 sensor display under DISPLAY button. For the first round, the value was between 0.2 to 0.9 V . For the 2nd round, it was 3.8 to 3.9V.



This is weird...Did i missed out anything? Must i wait until the engine is warmed up before taking the reading from O2 sensor?


My car idling is quite stable in both open and close loop

yes, the engines should be warmed up.

if u idle ok with closed loop, then it should be ok

for more info see the s300 help

ok..i chose 'closed loop operation' after taking the car for a ride. The O2 sensor reading is changing constantly between 0.1V to 0.9V (I monitor the reading when car is idling). Is that ok? Or should it be stable at 0.5V?

By the way i tried to look for O2 sensor which is supposed to be at the exhaust manifold? Can't find it and hope it is not a missing O2 sensor. By the way i suppose hondata will throw out an error code if O2 sensor is missing?

honda76 wrote:ok..i chose 'closed loop operation' after taking the car for a ride. The O2 sensor reading is changing constantly between 0.1V to 0.9V (I monitor the reading when car is idling). Is that ok? Or should it be stable at 0.5V?

By the way i tried to look for O2 sensor which is supposed to be at the exhaust manifold? Can't find it and hope it is not a missing O2 sensor. By the way i suppose hondata will throw out an error code if O2 sensor is missing?

it is Ok - should swing around 0.5v. u tune the strim (under closed loop) to make the o2 swings as small and tight as possible

do u have a cat? again there is stuff in the help and on the site if u need moreinfo

Johnny_9 wrote:

honda76 wrote:ok..i chose 'closed loop operation' after taking the car for a ride. The O2 sensor reading is changing constantly between 0.1V to 0.9V (I monitor the reading when car is idling). Is that ok? Or should it be stable at 0.5V?

By the way i tried to look for O2 sensor which is supposed to be at the exhaust manifold? Can't find it and hope it is not a missing O2 sensor. By the way i suppose hondata will throw out an error code if O2 sensor is missing?

it is Ok - should swing around 0.5v. u tune the strim (under closed loop) to make the o2 swings as small and tight as possible

do u have a cat? again there is stuff in the help and on the site if u need moreinfo

Thank Johnny, you have been really helpful. I am new to hondata, trying to find a starting point to fine-tune what my tuner had done in 30min. E.g. adjust the fuel cut off (MAP) so that car will shiver less at low rpm. I am considering switching my air intake pipe from fat tummy to straight pipe with open pod filter. I believe i cant just switch over if in open loop. Figuring out whether i can safely change the air intake pipe after I switched to CLOSED loop.

Just one other thing i just read, the O2 should ideally swing across the 0.51v about 3 times a second for best closed loop operation