Alvin007:
Op...I'm also a DIY guy, but I think these readings are self explanatory...regarding your STFT(Short fuel trim), it should fluctuate between +/- 10...when you get double digits, there's a problem...the positive readings posits a rich mixture, while the negative reading connotes a lean mixture...you should note that the LTFT...(Long fuel trim) is what the ecm saves over time, from the readings of the short fuel trim..(STFT)...during a lean mixture, the ecm tells the engine to pour in more fuel for optimum combustion, while, during a rich mixture, fuel is reduced...also note that, the readings from the 02(oxygen) sensors are responsible for the STFT and LTFT...on a 14:7:1 ratio..(air/fuel ratio)...there's so much to explain here...besides your vehicle is on idle...drive and monitor how your o2 sensors flunctuate, as well as your STFT and LTFT...via 'Live data' on your scanner and post pictures.

i would do that boss.. Thanks a lot...

olaboy1:
Try and find out the required temperature your car should be. I think 85 degrees should be the temp when fully warmed, so your 70 degrees is number one suspect before oxygen sensor. Change thermostat first and if it still doesn’t work then change engine coolant temperature sensor or if you have the money just change both at once.
When I changed mine there was a very big difference in MPG, also clean your MAF sensor thoroughly, find YouTube videos on how to thoroughly clean a MAF.

As for your fuel trims, the only way to know if they are working and not just static is to raise your RPM at 1500 and 2500 to see if your STFT will change, it should change under normal circumstances because you are adding load by raising your RPM.

I hope I have been able to help in my little understanding since I’m not a mechanic.

OP Make I borrow small space from your thread, does any car guru in the house know much about in tank fuel filter for Toyota engine 1AZ-FE, some say I don’t ever need to change it which I doubt. I need help on this as I read this could cause engine lean condition.

Thanks boss.. How do I clean the MAF sensors.. My fan dosent come on when I turn ignition.. It only comes on when the car becomes hot or I use AC.. Based on this.. Does it mean my thermostat is still good.. And yes.. I posted the data pics not up to 5 mins after starting the car.. So I will say.. It hasn't really warmed to max..

obekediamondfuto:
there is only one person I know who can read and interprete live data.......
cc honmusa

1 Im a diy guy with experience in very few brands.... Toyota inclusive

2 its not obiekediamondautos Lolz, check again.

3 I'm not really into Honda


but nonetheless, ur car hasn't reached optimu. temp from the readings, ur ignition timing advance is OK considering ur car is at idle,
The following are known good voltages for air-fuel sensors compiled over the last few years: 3.3 V (Toyota), 2.8 V (Honda), 1.9 V (Hyundai), 2.44 V (Subaru), 1.47 V (Nissan), after vehicle has reached operating temp.

don't bother too much about ignition timing, its. complicated to understand than to set. it simply is the timing of the spark in the combustion chamber for efficiency..... when the spark is introduced just before the piston reaches top dead center so that it can comp!etely burn the fuel inside. the concept is still dicey to me but It easier to set.


since ur o2 sensors are generating volts I think the pid would indicate that the volts are below spec


also u need to move the vehicle around for like 50blocks to generate stft and ltft

You are right.. The car was just getting warmed up... Sorry about the error in your name.. Hahahah

Kashif:
You were playing with your scanner, so you are inviting us to come play with you? Well, let me finish my home work first.

But really, nothing to interpret. Your scanner is DIY, and there is no specified diagnostic target.

hahahq..overplay dey worry me..well.. I just wanted to know what all the plenty values am seeing means..

Alvin007:
Op...regarding the pics of the o2 sensor readings you posted here...it looks ok...provided the downstream o2 sensor(o2 sensor 2) doesn't switch readings as frequently as the o2 sensor 1(exhaust manifold sensor)..in the case of your car...while on idle..it's normal for both of them to switch readings intermittently while your vehicle moves...but, on idle, the downstream sensor should change less frequently, while the sensor 1 switches more often...
If both switch at the same rate while your car is on idle, it means you have a catalyst issue..I'm not sure your car uses a mass air flow sensor.

to be honest.. My exhaust doesn't even have catalyst.. As my panel beater told me sha

captainking:
to be honest.. My exhaust doesn't even have catalyst.. As my panel beater told me sha

You could either get a replacement catalyst converter or do the defouler trick.

Alvin007:


You could either get a replacement catalyst converter or do the defouler trick.

i think I did the defouler trick myself.. I don't know if I got it right.. I would snap and post it here on Saturday..

captainking:
i think I did the defouler trick myself.. I don't know if I got it right.. I would snap and post it here on Saturday..

you can confirm from the downstream o2sensor readings at idle, or from the STFT, or from the disappearance of the Generic P0420(catalyst system efficiency below threshold bank1..)code.

Alvin007:

you can confirm from the downstream o2sensor readings at idle, or from the STFT, or from the disappearance of the Generic P0420(catalyst system efficiency below threshold bank1..)code.

my brother.. I don't think i gotten that code before..but I know I don't have catalyst in the car.. Thou my panel also did that manual catalyst... Hehehee.. What should the reading of the 02sensor at idle be pls.. I wanna learn.

captainking:
my brother.. I don't think i gotten that code before..but I know I don't have catalyst in the car.. Thou my panel also did that manual catalyst... Hehehee.. What should the reading of the 02sensor at idle be pls.. I wanna learn.

If you've never gotten the code before, it prolly means that after the removal of the stock catalyst converter that came with your car, your car either had other issues, ranging from a faulty o2 sensor, to a misfire...that was prolly why the code never came up..or maybe the Kinda catalyst your panel fixed, did the job...if the latter is the case, you don't need the defouler trick. Regarding the downstream readings, there isn't a specific reading that can be regarded as 'supposed' or 'normal'...it all depends on the sensitivity of the o2(downstream) sensor...but, for a car like yours running on an i4 engine, with only two o2(oxygen) sensors, the downstream o2 sensor shouldn't fluctuate as often as the o2 sensor 1, bank 1...instead it should switch readings at intervals when the car is on idle, having attained optimum temperature..kindly, note that the moment you start your engine when it's cold, you may not get accurate o2 sensor readings and STFT...but the ecm stores the last LTFT percentage, till the next time you start the car...if your STFT and LTFT still read zero as you posted above, rev your car's rpm towards 2,500rpm and see if there's a change....but while you're driving, both o2 sensors should switch readings intermittently.

Alvin007:


If you've never gotten the code before, it prolly means that after the removal of the stock catalyst converter that came with your car, your car either had other issues, ranging from a faulty o2 sensor, to a misfire...that was prolly why the code never came up..or maybe the Kinda catalyst your panel fixed, did the job...if the latter is the case, you don't need the defouler trick. Regarding the downstream readings, there isn't a specific reading that can be regarded as 'supposed' or 'normal'...it all depends on the sensitivity of the o2(downstream) sensor...but, for a car like yours running on an i4 engine, with only two o2(oxygen) sensors, the downstream o2 sensor shouldn't fluctuate as often as the o2 sensor 1, bank 1...instead it should switch readings at intervals when the car is on idle, having attained optimum temperature..kindly, note that the moment you start your engine when it's cold, you may not get accurate o2 sensor readings and STFT...but the ecm stores the last LTFT percentage, till the next time you start the car...if your STFT and LTFT still read zero as you posted above, rev your car's rpm towards 2,500rpm and see if there's a change....but while you're driving, both o2 sensors should switch readings intermittently.

Whoa... Highly informative..i appreciate your time and response boss.. You the bomb.. Would do such.. And revert back...

captainking:

Thanks boss.. How do I clean the MAF sensors.. My fan dosent come on when I turn ignition.. It only comes on when the car becomes hot or I use AC.. Based on this.. Does it mean my thermostat is still good.. And yes.. I posted the data pics not up to 5 mins after starting the car.. So I will say.. It hasn't really warmed to max..

That’s how the fan is designed to work and also the icon designed to show you when your engine overheats will also stay on until engine is properly warmed and that goes off, the fan will kick in once the temperature rises above 85 degrees or so. Drive the car around for 10 mins and see if your temperature rises towards 85 degrees. Your main focus is the temperature when engine is fully warmed, that’s your only pointer or diagnosis to know if you have a bad thermostat or ECTS, and not the fan behavior.


https://www.youtube.com/watch?v=xVoNOuSLYTM

When I cleaned mine fuel trim moved from 20 to 13, I watched many videos and did second and third cleaning, the second and third cleaning I didn’t just spray the lens with MAF cleaner, I used ear cotton bud to scrub the filament and lens inside gently and my trim went down to like 2 immediately, just so you keep that in mind that first cleaning may not do the magic and also find some electrical contact cleaner to spray both connectors of the MAF for partial contact problem.

olaboy1:


That’s how the fan is designed to work and also the icon designed to show you when your engine overheats will also stay on until engine is properly warmed and that goes off, the fan will kick in once the temperature rises above 85 degrees or so. Drive the car around for 10 mins and see if your temperature rises towards 85 degrees. Your main focus is the temperature when engine is fully warmed, that’s your only pointer or diagnosis to know if you have a bad thermostat or ECTS, and not the fan behavior.


https://www.youtube.com/watch?v=xVoNOuSLYTM

When I cleaned mine fuel trim moved from 20 to 13, I watched many videos and did second and third cleaning, the second and third cleaning I didn’t just spray the lens with MAF cleaner, I used ear cotton bud to scrub the filament and lens inside gently and my trim went down to like 2 immediately, just so you keep that in mind that first cleaning may not do the magic and also find some electrical contact cleaner to spray both connectors of the MAF for partial contact problem.

Thanks a lot boss.. Is there also anything like oxygen sensor cleaner..?.. Are u also saying I should look fo MAF cleaner in the market to buy??

captainking:

Thanks a lot boss.. Is there also anything like oxygen sensor cleaner..?.. Are u also saying I should look fo MAF cleaner in the market to buy??

If you can find a dedicated MAF cleaner, otherwise use normal carburetor cleaner. If your oxygen sensor is above 100k km then just change it.

olaboy1:


If you can find a dedicated MAF cleaner, otherwise use normal carburetor cleaner. If your oxygen sensor is above 100k km then just change it.

Spot on..but some oxygen sensors go beyond the 100k life span...one can simply remove the sensor, shake, while holding close to one's ear...if there are sounds like lil objects moving around inside the sensor, then it means the sensory part is damaged..that kinda sensor can't be revived through cleansing...it is better replaced..but, if it doesn't sound that way, cleaning it might revive the sensory part....but the best way to ascertain whether an oxygen sensor still functions properly is to either check its readings via a diagnostic tool..or through a voltage meter.
N.B. For best results, leave the oxygen sensor in petrol..for a long time..preferably overnight..this doesn't include the cable tho.

olaboy1:


If you can find a dedicated MAF cleaner, otherwise use normal carburetor cleaner. If your oxygen sensor is above 100k km then just change it.

thanks a lot boss...

Alvin007:


Spot on..but some oxygen sensors go beyond the 100k life span...one can simply remove the sensor, shake, while holding close to one's ear...if there are sounds like lil objects moving around inside the sensor, then it means the sensory part is damaged..that kinda sensor can't be revived through cleansing...it is better replaced..but, if it doesn't sound that way, cleaning it might revive the sensory part....but the best way to ascertain whether an oxygen sensor still functions properly is to either check its readings via a diagnostic tool..or through a voltage meter.
N.B. For best results, leave the oxygen sensor in petrol..for a long time..preferably overnight..this doesn't include the cable tho.

wow... I would try using the petrol stuff to clean the oxygen sensor.. overnight abi..would try it.. Am learning wella oo

Pls don't use carburetor to clean your MAF if u don't want to shorten its lifespan,look for electronic cleaning fluid. And concerning the issue of O2 sensor .,If it is bad just change it ,it no use try to revive already dead cos its efficiency has already degraded due to ageing even u succeeded in waking it up .You need O2 sensor that is working at its full potential to give u good fuel management function.

captainking:

I know some of them but not sure what they really mean.. Thanks a lot for the enlightenment... It was fulfilling.. Erm..am trying to compare mine with manufacturers specs..

But becareful in comparing with manufacters as normally you would be given a reading that ranges between certain figures

Data live stream is good for those who do car tunning


Remember if Its not broke dont fix it

ZIMDRILL:


But becareful in comparing with manufacters as normally you would given a reading that ranges between certain figures

Data live stream is good for especially fot tunning


Remember if Its not broke dont fix it

Thanks boss.. I appreciate

honmusa:
Pls don't use carburetor to clean your MAF if u don't want to shorten its lifespan,look for electronic cleaning fluid. And concerning the issue of O2 sensor .,If it is bad just change it ,it no use try to revive already dead cos its efficiency has already degraded due to ageing even u succeeded in waking it up .You need O2 sensor that is working at its full potential to give u good fuel management function.

thanks boss. I would do as advised..