LX470 reduced power, poor idle, 25L/100km fuel usage. Techstream data included, o2 sensor? (3 Viewers)

[kagey]

Hey everyone, quite new to techstream data and no sure if I've identified an issue and/or what it actually is. In the images below I've noticed that AFS B1S1, AFS B1S3 and AF FT B1S3 are showing values of zero.

This data was taken at idle after the car had warmed up and what not.

Any assistance on how to read this data would be amazing!

 

[joshAUST]

No great answer, but here's my input.
I use a cheap scancode reader purchased from Ebay on my 2003 UZJ100.
As far as I am aware, there are two O2 sensors between the engine and the Catalytic converters, and two after.
As far as I am aware, again, the first two are the only ones that effect the fuel consumption, and performance, while the two after the cat are there more for emission control stuff.
If the first two sensors are reporting zero volts, then they may be disconnected, or faulty, and could indeed affect fuel consumption and performance.
However, I doubt that both would fail at the same time, unless they were both disconnected.
Perhaps invest in a cheap scancode reader from ebay and see what they report re the front O2 sensors?
I've used the techstream program before, but cannot remember the details re the O2 sensors.

 

[kagey]

A little bit more info - set techstream to record and did a run down the road. These are the results from the run.

Not sure what the correct values are here for a 1998 LX470. Feel like the zero one should have a value?

 

[joshAUST]

A little bit more info - set techstream to record and did a run down the road. These are the results from the run.

Not sure what the correct values are here for a 1998 LX470. Feel like the zero one should have a value?

View attachment 3189271

The 02 sensors should not be zero values.
I would check the wiring going to those that report zero volts.
Hopefully just a damaged or broken wire.
The value should be between 0.1v and 0.9v.

AFAIR, the rear sensors do not effect the performance or otherwise of the vehicle - they are their for environmental control purposes.
I have heard otherwise from some people however, so not entirely sure, but assume that the front sensors are the most important.

 

[joshAUST]

How To Confirm Your Toyota's Got A Failing Oxygen Sensor | Toyota Parts Center Blog

Like All Sensors On A Vehicle, Oxygen Sensors Wear Out. Keep An Eye Out For These Common Symptoms.

parts.olathetoyota.com

 

[2001LC]

Can't say I look at this data stream, all that much. But I sure don't recall, ever seeing S3. Which would indicate a 3rd sensor. Perhaps you've wrong year inputted during log on. The different years, give different data, depending on CPU is my understanding. The VVT engine gives the most, and tech stream finds its make,model and year automatically and inputs VIN IIRC. Older models, need vehicle make, model and year manually set.

When I do look at A/F & O2 sensors. I like to watch sensor values, as I manipulate fuel trims. See how they behave and look at response times.

07 LX470 which is 2UZ.fe VVT. VVT S1 are A/F sensors, S2 are O2 sensors. Pre VVT, both S1 & S2 are O2 sensors.

 

[2001LC]

With our cheap ebay tech stream hook-up and boot-leg software, we're limited. Toyota tech school (not 4.7l specific). Talks about isolating one bk or even I fuel injector, at a time. This takes the real full blown Tech stream CPU box, with all attachment!

 

[kagey]

Can't say I look at this data stream, all that much. But I sure don't recall, ever seeing S3. Which would indicate a 3rd sensor. Perhaps you've wrong year inputted during log on. The different years, give different data, depending on CPU is my understanding. The VVT engine gives the most, and tech stream finds its make,model and year automatically and inputs VIN IIRC. Older models, need vehicle make, model and year manually set.

When I do look at A/F & O2 sensors. I like to watch sensor values, as I manipulate fuel trims. See how they behave and look at response times.

07 LX470 which is 2UZ.fe VVT. VVT S1 are A/F sensors, S2 are O2 sensors. Pre VVT, both S1 & S2 are O2 sensors.
View attachment 3189794

I found it challenging to locate the correct model. When techstream is set to the Australian region it doesn't have year models, instead a series of number codes. For example 0008. There are 4 numerical code options, I went from lowest to highest until I got O2 sensors. The first 2 options had no O2 sensor fields at all. So kinda took what I could get.

I'm unsure if setting the region to USA would even work?

Was just thinking that there are 4 sensor total in the vehicle and there's 4 readings. But yeah, I kinda hate techstream. haha