O2 Sensor Readings!
 

Is the fuel trim built into the o2 sensor readings on a classic subaru?
i have a tactrix cable on evoscan for my 97 subaru and my o2 average is pretty much always above 117%

when i give it some beans it drops to 97% for a split second and back up.

pretty much stays between 117-127%

Will test again for vac leaks tomorrow, i been over all hoses again today.

pretty much want to know what the o2 average, min and maximum should be on the cars, and if my o2 sensor is working good.

my car is running rich.

thanks for reading!

Why do u think this is % there. I belive this is raw data value, in wich zero modification would be 128. From where u know, that your car is running rich? If u have vac leaks, it should be lean on mild crusing and very rich at wot driving. Might be aswell dead maf or dead/misreading o2 sensor that causes this.

MAF has been replaced with a new unit and the readings seem to be solid (no abnormal readings?).

Lots of back-firing and pops happening and i dont even have a vta BOV.

If its a vac leak, surely my manifold pressure reading would fluctuate considerably?

oh right, im pretty sure its percentage become of the evo scan program.

The actual O2 sensor signal is a voltage between zero and one volt usually oscillating when in closed loop

the ecu uses the signal voltage to adjust the stretch fueling off boost under cruise type conditions. The readings you show are not real they are calculated and definitely not a percentage whatever evoscan says, the air/fuel correction column showing zeros, -6, -2 etc is the actual correction amount the ecu has applied to the injectors to achieve the stoic value its reading from the O2 sensor.

Its a narrow band sensor ... that is only used for stoic correction

so there is no way to test if the o2 sensor is not working correctly other than piggybacking of the o2 signal wire going into the ecu? I read i can only test it accurately with an oscilloscope.

ive brought a bosch ls02 anyway!

About the air fuel correction, i have an issue where ill be driving and at certain times i will come close to stalling or i stall.

I will be driving on the motorway, and i will get a solid CEL which will go once i get to idle.

i have three total error codes after a motorway trip.

54- immobilizer module
33-Vehicle speed sensor 2
24-Idle air control valve.

i get around error 54 by cranking the car, letting off and then cranking again it splutters into life.

ive cleaned and changed the iacv.

ive also double checked the timing, checked for vac leaks etc.

ive replaced the maf with a genuine refurburished one from ebay.

ive noticed i get this more and more as temperature decreases.

if you could have a wizz through this log i just posted that would be awesome.

so at the beginning im idiling (then i take a bite at 3k rpms cause paddle clutch ;) ) then drive a lilttle to a traffic light where i put the clutch it and the revs drop to 500, in an attempt to not stall, i rev a little and it makes no difference and drops till the air fuel leans out back to 0 correction.

during the stallish moment i have a airfuelcorrection of +18 and +31, when reved to 2k the airfuel correction gets to 0, then it add fuels again when its idling.

i notice when i revved my TPS value didnt change (bad logging rate on evoscan?) but my boost solenoid duty went to 90% ! however the relative manifold pressure didn't change?.

is my car begging for a remap or do i have a underlying issue? i personally think its the second as i only have, kn panel filter, 3" decat exhaust system and a 4-2-1 equalish length headers.

the only thing that comes to mind is maybe that refurbished MAF isnt upto scratch or the o2 sensor was toosh.

ive triple checked the vac lines for damage etc, ive changed the wastegate and the preload due to the fact that i get full boost of 0.9bar by 3.5k and then it will drop to -0.8 by 3.8k then back to 0.9 bar by 4k!

would be awesome if you could just tip me on some common problems or any sort of link to increase my mapping knowledge!

thanks alot