Understanding Open loop / Closed loop Basics

In this video I give you a basic description of "open loop" VS "closed loop"

This may seem very basic however the question has been asked numerous times, whats the deference between the two, so I thought this would be a great example

With this knowledge I came to the conclusion without looking at the vehicle, how the engines low coolant temp was directly related to poor fuel mileage

[speedchopwtf]

11 years later and this was super helpful. thank you!

[hamzacar]

One of the best comprehensive definitions of open/close loop
Thankyou Sir

[upptowne]

I just purchased a scanner and this type of basics is exactly what want to learn. Thanks a lot

[liam]

great that you go into so much detail in youtube video.... NO 1 mechanic on you tube

[SuperCarfix]

I think both of you supper techs(Paul and Will)are inspiring the whole techs community.

Thank you

[ScannerDanner]

a comment on the video itself. i agree with the assessment a stuck open thermostat will cause extended open loop operation as well as a richer fuel.curve from lower coolant temp.
the fluctuating O2 in open loop was weird but doesn't change the call or the theory behind the poor fuel.mileage.

[wedreamtogether]

I really appreciate you taking the time to make this video. In videos by "real fixes real fast" Duane often mentions open and closed loop, now I have a better understanding of what that is. Thank you!

[SchneiderClassics]

nice, my prof shared this video with us, great explanation on open vs closed loop.

[nicholasvonrhine]

How cool the engine is constantly adjusting to be most efficient.

[medicaltechnicalathlete]

wow I learned all that easier than my college class haha and the best part is I didn't get bored! nice work!

[joshuaboyell]

Love how the philly accent gets stronger and stronger as the video goes. Sounds like home.

[AGuysGarage]

Great video. Thank you for the info. My ride is running cool right now too. "thinking the thermostat is probably toast" lower hose on the radiator is cool and upper hose is hot. but that explains my crap mpg for sure lol. i figured it was something like that. plannin on doin it when it gets a lil warmer.

[spelunkerd]

Thanks for responding. On my 1998 Ram the O2 sensor page seems unsupported, even though I have the full enhanced package. I think it may be an issue with the truck. I don't see the typical O2 sensor pattern, more of a truncated one, which makes me think that it's an issue with the refresh rate sending data down the OBDII ports. I put a generic scope on one sensor, backprobed off the wires, and the typical sinusoidal swings are present there. I'll try it on some other vehicles.

[Amopower]

Once in closed loop, the feedback from the O2 sensors gets used by the ECU, and then we should see the ups and downs...add fuel/take away...repeat. When in open loop, the O2 signal is not used, so we should see something steady. The text that says "open loop" in that software might be coming from the software itself and not the ECU.

[tragichero]

Very helpful! So awesome how much you can learn by watching repair videos

[reweydewy]

Great work as usual! I really dig the older style Chevy/GMC trucks. Thanks for taking the time for this vid. Lets see part 2!

[beastlychase]

Hello I am getting a p1129 on my Jeep Liberty closed loop will not achieve and I'm dumping a lot of gas into it where part two or what did you do to fix your problem

[danielandujar]

I have a question.
My Honda pilot 2003. 3.5
I hook up the scanner and with just the
Switch on it shows a close loop
Without starting the unit.
Is this normal?
And if not possible cause.
Please thank's

[baxrok.]

Great job and a very thorough explanation.

[robinsonsauto]

while in generic the only way i am aware of is on the "o2 sensor" monitor page i think its the 6th tab on the top
when you select an o2 and start monitoring above the graph you will see the fuel system status, open or closed
now while in enhance mode you can do the same however you also have the option to select it as one of the monitors on any of the meter, graphs and grids (this may not be an option on all makes and models) hope this helps