BTW you also mentioned STFT going down to -3.8, that is to say the the car is withdrawing fuel when the gas pedal is depressed, that is a good example of a vacuum leak, go to YouTube and study how to find vacuum leak, it is a piece of cake, even without a smoke machine, maybe you did not connect a hose properly, so a rogue and unmeterd air is finding its way into the engine. At idle it matters a lot because only a little air is needed but at wide open throttle its effect is diminished because there is way more metered air in the engine.
Don't ignore the STFT because that is what the computer is doing now and LTFT is what it has been doing, which is a product of STFT.

cocoduck:
BTW you also mentioned STFT going down to -3.8, that is to say the the car is withdrawing fuel when the gas pedal is depressed, that is a good example of a vacuum leak, go to YouTube and study how to find vacuum leak, it is a piece of cake, even without a smoke machine, maybe you did not connect a hose properly, so a rogue and unmeterd air is finding its way into the engine. At idle it matters a lot because only a little air is needed but at wide open throttle its effect is diminished because there is way more metered air in the engine.
Don't ignore the STFT because that is what the computer is doing now and LTFT is what it has been doing, which is a product of STFT.

What is a vacuum leak? when unmetered air is entering the combustion chamber; right?
okay, i depress the gas pedal while parked and STFT dips to negative 3.8% (maximum av seen it dip to) . . which u said d car is withdrawing fuel . .
but i dont understand d concept . . i tot depressing the gas pedal opens d throttle body for more air . .. and more air would require more fuel . .
then how come i depress d gas pedal and the car is withdrawing fuel . . . that sentence alone is confusing me and i would love it if you broke it down for me . . . .i wil check Youtube now for how to find a vacuum leak . ..
In short, lemme go downstairs now and start working on this car . . . . Today is Saturday and I am going to be my own mechanic by fire by force . .

Yes remember the soichiometry of car engines that is fuel air ratio, 14.7 parts of air to 1 part of fuel, at closes loop the computer will be very obsessive with this ratio, so if it is withdrawing fuel it simply means that there is too much fuel, at wide open throttle the computer knows its at wide open throttle, so it will adjust to that, but it must maintain the stoichiometric ratio as far as it is at closed loop, WOT or not, so an improvement when you open the throttle is that the big air in the engine will displace the rogue air and at idle the effects of the rogue air will be felt worse. But before anything check that TPS, these must not be a signal drop out at all for all to work.

cocoduck:
....

Okay i wil check the TPS again . . . and check for a vacuum leak . . i just hope its not something too serious like on the intake manifold, EGR , PCV valve or brake booster . . .I will be back in say, 2hrs
Thanks a million . . .

makavele:


Okay i wil check the TPS again . . . and check for a vacuum leak . . i just hope its not something too serious like on the intake manifold, EGR , PCV valve or brake booster . . .I will be back in say, 2hrs
Thanks a million . . .

Your main problem is not the vacuum leak for now, your car does not throttle well, so, with the signal drop out your reported, it means the computer is seeing that erratic signal and thinks you are the one doing it, and it reacts based on the signals it receives, it is a kind of garbage in garbage out thing, so test that part and verify it works well.

cocoduck:
Your main problem is not the vacuum leak for now, your car does not throttle well, so, with the signal drop out your reported, it means the computer is seeing that erratic signal and thinks you are the one doing it, and it reacts based on the signals it receives, it is a kind of garbage in garbage out thing, so test that part and verify it works well.

1. Yes, i have tested the TPS and it does cut signal somewhere around 2k RPM . . . so i think i should be getting a new one.
2. Oxygen sensor bank 1 reports a constant 0.175 voltage . . which shows system is too lean . . . i learnt ideal voltage should be somwhere around plus minus 0.450 . . . when i gas d car, it rises to 0.9; but on releasing the pedal, drops to 0.175 and remains there. . . dead oxygen sensor ??
3. I was able to achieve -8.9% STFT and LTFT has dropped to 10.2% . . . is the ECM relearning fuel trims?
4. I discovered the fans were set to always on . . .as i noticed a wire used for bridging the fan relays . . i removed it. . .
5. Fans now come on at 93 degress celcius . . . blow for a minute and turn off at 90 degree . . . once it gets to 93 degrees; they come on again . . factory spec i guess . . .
6. After tampering with the gas pedal assembly; car idles at 700 RPM and about 800+ with full load . . engine is super quiet
7. The only thing I am concerned about now are my fuel trims . . .cos I know for sure I would be changing the TPS anytime soon . .

Awaiting your input sir . . .

Thanks

your car's problem is now more on the gas pedal potentiometer, your 02 sensors are working, for further test, if your car has a brake booster hose disconnect it and see if the voltage goes up, BTW I believe that that thing is not an O2 sensor but an AF sensor I think air fuel ratio sensor or something, so it does not react like your average oxygen sensor, sometimes you may even think that it is a faulty O2 sensor so don't touch it. Just manage till you get a new TPS.
Make sure you study your owner's manual and use the recommended oils and fluids, it is all on the manual.

cocoduck:
your car's problem is now more on the gas pedal potentiometer, your 02 sensors are working, for further test, if your car has a brake booster hose disconnect it and see if the voltage goes up, BTW I believe that that thing is not an O2 sensor but an AF sensor I think air fuel ratio sensor or something, so it does not react like your average oxygen sensor, sometimes you may even think that it is a faulty O2 sensor so don't touch it. Just manage till you get a new TPS.
Make sure you study your owner's manual and use the recommended oils and fluids, it is all on the manual.

Okay thanks, i will do the check for the brake booster thing in the morning . . .
Meanwhile, i couldn't perform a vacuum leak test ... the ones i saw on youtube that didnt require a smoke machine . . required either propane or a cigarette to simulate smoke . . I don't have a propane tank; and I don't smoke . . .so i guess, i will have to take d vehicle to Mr G for a vacuum leak test afterall. And hopefully change the TPS there too . . .

The fuel trim learn and relearn is not static, it is dynamic, Toyota uses the AF sensor for their upstream measurement and the normal 02 sensor for the downstream measurement, and that one does what you typed above. here are some videos for more enlightenment

https://www.youtube.com/watch?v=XQYDwIWS6Ho&itct=CA8QpDAYDSITCISj_9u0k8wCFRDAFgodFV0GGVISU2NocsO2ZGluZ2VyJ3MgYm94&hl=en&client=mv-google&gl=US
part 2

https://www.youtube.com/watch?v=K8GLH6ubXoc&itct=CBoQpDAYACITCKGE6OW5k8wCFcGJFgodnvkOQzIGcmVsbWZ1SPrQy6yI-ICDXQ%3D%3D&gl=US&client=mv-google&hl=en


https://www.youtube.com/watch?v=yLxu2Z5OfTM&itct=CDgQpDAiEwjd4qaSuZPMAhWShRYKHbUtBYAyC2M0LXZpZGVvcy11WhhVQ3JSUDRjNTBtZDBDQU54MDZLZkpoN2c%3D&hl=en&gl=US&client=mv-google



https://www.youtube.com/watch?v=uxRBViOV6DE&itct=CCsQpDAYACITCLX38pa3k8wCFcMRFgodNrsCkVIyb2xkc2tvb2wgZnVuayBob3cgdG8gbWFrZSBhIGhvbWVtYWRlIHNtb2tlIG1hY2hpbmU%3D&hl=en&client=mv-google&gl=US

and how to make your own smoke machine,

https://www.youtube.com/watch?v=FFlyAqiYMro&itct=CCkQpDAYASITCLX38pa3k8wCFcMRFgodNrsCkVIyb2xkc2tvb2wgZnVuayBob3cgdG8gbWFrZSBhIGhvbWVtYWRlIHNtb2tlIG1hY2hpbmU%3D&hl=en&client=mv-google&gl=US

you can use your lungs if you don't have an air pump like you saw in the video.
some use cigarettes.

https://www.youtube.com/watch?v=RFQBa-nqBPo?list=PLD2809EEC7BAAF989

makavele:
^^^
The scanner is able to stream live data . . . what exactly do i check for in the live data ?

Yes, i can see the throttle body, but the way it's positioned is scary . . .

I am afraid, while cleaning it myself, the cleaning fluid might actually drip inward along with the dirt . . and cause more damage.

Unless i of course bring out the whole throttle body, and i dont have the tools for that.

Hi I saw in your thread that you deal in Rand if you still do how can I get your number?Thanks

Awango:



Hi I saw in your thread that you deal in Rand if you still do how can I get your number?Thanks

Yes sir, send me a PM sir
Thanks

makavele:

Yes sir, send me a PM sir Thanks

OK PM sent please check and revert.Thanks

Awango:


OK PM sent please check and revert.Thanks

i replied u sir