Short Term and Long Term Fuel Trims, Oxygen 02 sensors Explained.

Short and long term fuel trims, oxygen (02) sensors, open and closed loop explained.
#cars #howthingswork #fuel #oxygensensor #closedloop

[douglasjre]

You're wrong. Bank one sensor 2 is after the cat. That's telling you how good the cat is working. You need to be reading bank one sensor one

[AFMIDS]

What's up my friend nice to meet you hope your day is going well! I was watching the fuel trim videos and im trying to understand and comprehend it but im struggling to because i have a learning disability. I like your videos your doing a good job helping people and i want you to continue bringing more fuel trim videos. I struggle alot to understand and comprehend but if the person teaches me in a way where my brain can understand and comprehend i can become very good at it.

[davidwoods]

Hi, really good to see something new from you. One question, I was under the impression that the#2 o2 sensor was not supposed to fluctuate in voltage.

[StationRussification]

Long Term is the window of time the adaptive memory dictates the fuel trim, Short Term is live data calculating to learn the parameters for the adaptive memory to update the Long Term. The O2 sensor signals lean below .45 volts & rich above .45. The Engine Controller only cares about that threshold & uses that to determine fuel trim. .. in other words the computer calculates the % of time that the O2 sensor is past the threshold of .45 volts & does that each time the threshold is crossed.

[PeterHernandez-lgeh]

Excellent now I know what I'm looking at on my live data

[leroylatham]

I would like to thank you for your videos on understanding what the machine is telling you about the oxygen sensor is telling you..I am 72 and disabled. I cannot afford to pay an overpriced mechanic to do the things I used to do to keep an engine running but now can’t because everything is electronic.I am hoping you can explain everything on these readers especially the extra functions like bi direction. Never in my life did I think I would need to learn all this crap.. I have a 2013 Silverado ltz. The amount of plastic is mind blowing but to replace what breaks is purely theft. Thank you again. Leroy Latham. Springfield louisiana

[Jencha]

Regarding next video: would be great if you could tell as what we should look at when buying used car - which data items to look at and what it means. Trims I suppose would be the first thing to look at to know if the engine is OK.

[powerfulsun]

You are reading wrong oxygen sensor. It is supposed to be bank1s1 which should be fluctuating ( if it is narrow band )
On the other hand, bank1s2 shouldn't be fluctuating normally, but i noticed when you rev the engine, bank1s2 didn't respond when tells me either the sensor is bad or wiring issue.

[avalentino]

Hey good video. I am currently trying diagnose a P2191 on my hyundai . My long term fuel trim is very high 30-40% 😮 . Any thoughts on what could be wrong?

[sbb]

Do you need both upstream and downstream o2 sensors for the fuel trim learn function ?

[kamranraza]

My vehicle has a long term fuel trim of minus 14
I have wagon r Suzuki
Fuel average is so poor
What should I do to get my reading closer to minus zero?

[mohammedsadiqueansari]

My 1FZ-FE without any O2 sensors from factory is reading -100% both short and long fuel trims. What could be the issue?

[chrisisho]

I have LTFT %25 and STFT zero with P0068 related to Map sensor,
I replaced Map sensor but LTFT still really high and not go less 18% whatever RPM
I attempted smoke test and no vacuum leak at all,
Replaced lowe pressure fuel pump with filter but still LTFT %25 with 900 RPM and Change to be %18 once touch accelerate paddle and stop at 18% even if 5000 RPM, may I know if you have an idea to solve this issue especially I replaced Bank1 sensor 1 O2 sensor ?

[comaradelee]

my 2010 suburban has a fast switching LTFT, is this ok?

[daryltang]

Hi. I have a high negative fuel trim but I can’t find any leaks. I used the smoke test machine(but I am not sure if it’s 100% going to confirm no leaks)

I have a ODB2 gauge showing -25 STFT(slowly dropping to -7) when I let go of my accelerator with no brakes. But this doesn’t happen all the time. Sometimes it’s goes to 0 in a second or sometimes it 0 right after I release the pedal.

I have replaced MAF sensor, MAP sensors and O2 sensors. PCV valve, IAC valve and EVAP valve and most recently spark plugs

Do you think I should change my fuel Injectors next? My tuner told me it’s very likely a vacuum leak(mentioned fuel pressure is fine and didn’t once mention an exhaust leak)

[scottykilmer]

i have a car where the bank 1 sensor 2 voltage only fluctuates between 0.700V and 0.850V at idle.
So I think my catalyst is in very good condition!

[shanthaamarasuriya]

Very nice video what should be right reading.idel& hi speed.

[cornelljones]

I really enjoyed your video. It gave me some ideas where to look. I went and bought a scan tool and 1 code came up. The code was P065E intake manifold tuning valve Bank 1. Do I need to change the bank I oxygen sensor or the tuning valve or both. Your reply back will surely be appreciated. Needing Help. I'm New at this. Thank you!

[ericrivera]

Thanks for the video, my obd2 scanner is reading that my o2 sensor is -2356ma any idea why is that?

[xnitro]

having an issue where long terms only go up in drive no vac/boost leaks possible between exhaust leak or something else