P0172 after fuel injectors.

[Bucket81]

You are showing 1x1 and 1x2 for O2 sensors. Your down street sensor bank 2 sensor 1 so you should look for a 2x1 sensor. There is only one bank 1 (upstream) sensor and one bank 2 (downstream) sensor.

It looks dead because it doesn’t exist. IMO


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These only have one bank of O2 sensors. So 1x1 is upstream and 1x2 is downstream.

I'm going to find some Denso part numbers and replace both.

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[19963.4lsr5]

My brain fart my grand Cherokee had the right cylinders as bank 1 and left as bank 2.

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[gamefreakgc]

Is this a bad down stream O2? And I can customize these if other data is needed.

O2 readings - YouTube

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No, that's normal function from what you provided. You have a 96-00 4Runner and that was taken while idling correct? The rear O2 sensor doesn't oscillate like the front one does except during certain throttle conditions. It also has very, very little impact on fuel trims. The front O2 sensor does all the heavy lifting which appears to be working fine since it's not zeroing out or maxing out. It's something like counting 8 oscillations in a 10 second period from the FSM.

Long-term Fuel Trim and Short-term Fuel Trim data would be super helpful here though. If you could, post what it shows while cruising (like on a highway or nice flat straight road) as well as at idle.

 

[Bucket81]

No, that's normal function from what you provided. You have a 96-00 4Runner and that was taken while idling correct? The rear O2 sensor doesn't oscillate like the front one does except during certain throttle conditions. It also has very, very little impact on fuel trims. The front O2 sensor does all the heavy lifting which appears to be working fine since it's not zeroing out or maxing out. It's something like counting 8 oscillations in a 10 second period from the FSM.



Long-term Fuel Trim and Short-term Fuel Trim data would be super helpful here though. If you could, post what it shows while cruising (like on a highway or nice flat straight road) as well as at idle.

The lower graph is the throttle position. I did give it a bit of gas.
I won't be able to take it in a high way it starts losing power and can't really get up to speed.

This is the fuel trims.
Fuel Trim - YouTube

 

[LittleCaesar]

No vacuum leaks and no huge problem with a rich/lean condition. I’d start with both 02 sensor replacement and go from there.

Does your software have the ability to freeze frame data, to see what the ECU sees when it trips the code?

 

[Bucket81]

No vacuum leaks and no huge problem with a rich/lean condition. I’d start with both 02 sensor replacement and go from there.

Does your software have the ability to freeze frame data, to see what the ECU sees when it trips the code?

I don't think it does. And I'm still not getting a CEL... I don't daily this so I'm not surprised. The O2 sensors are probably pretty old so I'll replace them.
I built a new dash board with my tablet. The downstream O2 sensor looks like it's working better. but seams to fall flat some times. I'm really not sure what I'm looking at on the file trims.

https://www.youtube.com/watch?v=GnPHz7pX-Iw&feature=youtu.be

 

[LittleCaesar]

With the fuel trims you want to have the short and long fuel trims within 10% of each other’s value, otherwise a vacuum leak or fuel problem would be present, usually making the long term number +- greater than the short term number depending on the problem. Your values look fine.

Can you post your MAF numbers as well?

 

[19963.4lsr5]

With the fuel trims you want to have the short and long fuel trims within 10% of each other’s value, otherwise a vacuum leak or fuel problem would be present, usually making the long term number +- greater than the short term number depending on the problem. Your values look fine.

Can you post your MAF numbers as well?

His long term going -21 causes the code


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[LittleCaesar]

His long term going -21 causes the code


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Must have missed that one

 

[Bucket81]

His long term going -21 causes the code


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I also didn't see it hit -21%.

I'll add Mass air flow rate tonight and take it for another drive.

Anybody notice at about 9:50 somebody decided to make a left turn right in front of me... This thing is pretty sketchy, needs brakes tires... You know normal stuff.

 

[Bucket81]

I got some data with MAF on it. It looks like it's working.
https://www.youtube.com/watch?v=6hg1PfST5GM&feature=youtu.be

If all the sensors look ok. Then I'm not sure what to replace.... Back to the fuel regulator?

 

[LittleCaesar]

I got some data with MAF on it. It looks like it's working.
https://www.youtube.com/watch?v=6hg1PfST5GM&feature=youtu.be

If all the sensors look ok. Then I'm not sure what to replace.... Back to the fuel regulator?

Does your idle ever get to 700rpms, +-50 when the engine is fully warmed up?

If I remember correctly my MAF reading is closer to 4 g/s at idle when warmed up but I will try and double check tomorrow.

 

[19963.4lsr5]

When the LTFT goes below 20 is the MAF still the same or does it change also?

Do you have any exhaust leaks?


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[LittleCaesar]

The more I think about your MAF readings I am going to say that your MAF, despite the cleaning, may be bad due to being out of calibration. The MAF, at least of this age, is like the throttle body where the values should be linear in nature as the RPMs increase.

 

[19963.4lsr5]

The more I think about your MAF readings I am going to say that your MAF, despite the cleaning, may be bad due to being out of calibration. The MAF, at least of this age, is like the throttle body where the values should be linear in nature as the RPMs increase.

I’ve been trying to find the PID for the MAF for my ScanGauge. It’s annoying I have to plug in my Innova scanner or use my app to see it.


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[LittleCaesar]

I’ve been trying to find the PID for the MAF for my ScanGauge. It’s annoying I have to plug in my Innova scanner or use my app to see it.


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I have to use my Launch.

It has been years since i looked at my MAF data but usually at idle the MAF reads close to or spot on the volume of the engine, or at least for me until one gets to anything under three liters.

I am thinking though the OP’s MAF has over time lost its ability to calibrate.:crutch:

 

[19963.4lsr5]

I have to use my Launch.

It has been years since i looked at my MAF data but usually at idle the MAF reads close to or spot on the volume of the engine, or at least for me until one gets to anything under three liters.

I am thinking though the OP’s MAF has over time lost its ability to calibrate.:crutch:

His LTFT was all over the place and it should be steady at idle. I think he’s definitely got a sensor giving bad info to the ECU and the O2 sensor sees the wrong fuel map and corrects the trims.


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[LittleCaesar]

So give or take my MAF reading at idle, fully warmed up reads about 4 grams per second. If the OP’s MAF is reading double that, then either that reading is based upon a bad MAF or the MAF is producing those numbers due to a normal than higher idle (which shouldn’t be the case).

If it was my rig I would clean the IAC and the TB well, then see if the values change at all. If the MAF value is still high, I would replace the MAF with a new one. I believe Denso makes one......

 

[gamefreakgc]

If he has the old turbine style MAF they cost $600 new. Junk yard units from 4Runners or V6 Camry's of similar years are interchangeable, I had a Camry MAF on mine for years.

 

[Bucket81]

Does your idle ever get to 700rpms, +-50 when the engine is fully warmed up?

If I remember correctly my MAF reading is closer to 4 g/s at idle when warmed up but I will try and double check tomorrow.

It seams to idle around 1000 RPM wich is high.

When the LTFT goes below 20 is the MAF still the same or does it change also?

Do you have any exhaust leaks?


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I don't think I have an exhaust leak. But I don't see the LTFT go over 20.

I’ve been trying to find the PID for the MAF for my ScanGauge. It’s annoying I have to plug in my Innova scanner or use my app to see it.


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I have an Innova scanner but couldn't figure out how to see live data in the app.

So give or take my MAF reading at idle, fully warmed up reads about 4 grams per second. If the OP’s MAF is reading double that, then either that reading is based upon a bad MAF or the MAF is producing those numbers due to a normal than higher idle (which shouldn’t be the case).

If it was my rig I would clean the IAC and the TB well, then see if the values change at all. If the MAF value is still high, I would replace the MAF with a new one. I believe Denso makes one......

It does seem to idle a bit high. What is the IAC? I did a light cleaning on the TB. But I could take it off and give it a good cleaning. I'm also wondering about the throttle position sensor. At idle shouldn't it read zero and not 10%?

If he has the old turbine style MAF they cost $600 new. Junk yard units from 4Runners or V6 Camry's of similar years are interchangeable, I had a Camry MAF on mine for years.

I am lucky and have a 99 I thnk a Denso is only $100.