Why do you guys need oxygen sensors and we don't ? (1 Viewer)

[ToyotaIsLife]

Hey guys, I am creating this thread not because I have a technical issue, just for the sake of curiosity. I hope you guys don't mind that I am bringing up a different series land cruiser in the 80 series section, its just that there is no other section with 1FZE experience.

When I say FJZ100L I mean: Middle east spec 1998-2007 100 series land cruiser which came with the GEN 2 1FZE same as the LC105 expect its IFS.

So I have been reading posts here in the 80 series section about oxygen sensors, and I cant help but wonder why many or all posts that I read claim that the 1FZE requires oxygen sensors to "run properly". While all of my experience with land cruisers equipped with the 1FZE (the GEN 2, or the 105 series/FJZ100L 1998+) run without oxygen sensors at all.

NOTE:

1. All GEN 1 1FZEs on 80 series land cruisers here in Qatar come with no oxygen sensors from the factory. I know this for sure because when I went to buy OEM exhaust manifolds for my FJZ100L last year at the Toyota spare parts store, the salesman asked me weather I wanted a manifold with a hole for the oxygen sensor or not. 1998+ FJZ100Ls come with the ports for oxygen sensors while 80 series manifolds do not come with oxygen sensor ports.

2. Out of all the people I know who own the FJZ100L run no oxygen sensors including me, the significant portion are running long tube headers however some run the factory exhaust manifold with the hole for the oxygen sensor plugged.

NOTE: I do understand the importance and the function of upstream oxygen sensor. It measures the air fuel ratio and feeds the info to the ECU to ensure "proper" or optimal operation.

So my real question is, why is it that an older, and simpler 80 series with the GEN 1 1FZE require a oxygen sensor to run properly, and the newer 1998+ FJZ100 with the *newer* GEN 2 1FZE does not ?.

I also read that the 80 series triggers a check engine light for you guys when there is a problem with the oxygen sensor. For us both the FJZ100L and the 80 series do not trigger the check engine light without the oxygen sensor. However when you install a OBD scanner, it does prompt an error that there is a fault with the oxygen sensor.

More importantly they seem to run perfectly fine ? No rough idle, no excessive fuel consumption. No signs of a excessively rich air fuel ratio (by checking spark plugs). The issue is I have not tried to buy a new O2 sensor and connect it to identify if there is a noticeable difference in how it runs. This is what I will be doing in the incoming week. I bought a new O2 sensor and will be wielding a whole in the exhaust and plugging it in to test.

My speculation to why: Middle east, Qatar especially does not have strict emissions requirements at all, which is why they are hardwired to not require the oxygen sensor. During the production of the FJZ100L (1998-2007), Qatar did not even have any emissions requirements.

Part number of the oxygen sensor that I purchased from Toyota spare parts: 89465-60260

Link: 02 Oxygen Sensor For Toyota Landcruiser FZJ100L 1998-2007 89465-60260 | eBay - https://www.ebay.com/itm/02-Oxygen-Sensor-For-Toyota-Landcruiser-FZJ100L-1998-2007-89465-60260-/164031753726

Image of the codes that appeared after scanning with an OBD scanner yesterday. Basically the same result of all the FJZ100Ls that I have scanned (in exception to the crankshaft position sensor). The MAF which is located in the intake manifold is the only component that is required(of course, otherwise the ECU would be completely blind). Unlike the 80 series which has a MAF attached to the air cleaner. The air temp sensor is an additional small sensor available in the FJZ100Ls which is never actually used here. Nobody runs it or so it seems from the hundred of cruisers I have seen.

 

[60 toy ota]

More a spectator in this thread, but I would guess the ecus are setup differently such that one's with an 02 sensor depend on its input for emissions reasons.

I had no idea there were 100s out there with 1fz and ifs

 

[Rifleman]

My speculation to why: Middle east, Qatar especially does not have strict emissions requirements at all, which is why they are hardwired to not require the oxygen sensor.

Bingo we have a winner!

 

[ToyotaIsLife]

Bingo we have a winner!

True we could end it here lol, however that still does not explain why people are claiming it is needed to run properly. Maybe its just a different ECU (fuel map, ignition timing, etc) configuration.. for you guys in the states

it is still interesting though that the engine is not running overly rich. None of the spark plugs I have inspected have shown signs of a overly rich air fuel ratio. MAF must be doing a great job doing all the heavy lifting.

 

[ToyotaIsLife]

More a spectator in this thread, but I would guess the ecus are setup differently such that one's with an 02 sensor depend on its input for emissions reasons.

I had no idea there were 100s out there with 1fz and ifs

Yes that makes sense Toyota must have hardcoded the ECU to require the O2s to be functioning to ensure the emissions are kept at a min.

 

[scottryana]

Correct, there are different ECU’s for countries that don’t require the OBDII emissions controls. For 1FZ’s in those areas the O2 sensors help the truck adjust fueling so that it isn’t too lean or too rich.

For countries without OBDII, the 1FZ just runs off of the fuel and load tables, in the ECU. I am sure it runs fairly rich since that is safe. Oddly though the O2 sensors can catch problems like a failing injector, intake air leak, etc. I am kind of surprised Toyota just didn’t use them on all the 1FZ’s. I guess they save some money not using them.

For a truck like yours, I would definitely add an aftermarket wideband O2 sensor in the exhaust.

 

[ToyotaIsLife]

Correct, there are different ECU’s for countries that don’t require the OBDII emissions controls. For 1FZ’s in those areas the O2 sensors help the truck adjust fueling so that it isn’t too lean or too rich.

For countries without OBDII, the 1FZ just runs off of the fuel and load tables, in the ECU. I am sure it runs fairly rich since that is safe. Oddly though the O2 sensors can catch problems like a failing injector, intake air leak, etc. I am kind of surprised Toyota just didn’t use them on all the 1FZ’s. I guess they save some money not using them.

For a truck like yours, I would definitely add an aftermarket wideband O2 sensor in the exhaust.

Great answer.

I did not know O2s had the capability to catch errors.

Before I attempt running a aftermarket wideband O2. I am curious to see if my vehicle runs differently with or without the factory O2 sensor. I imagine without getting technical it would be difficult to observe a difference.

So I will be taking it to a dyno jet before an after to see if having an O2 + air temp sensors running will in any way shape or form change the engines performance. It should be interesting. (BTW, bone stock GEN 2 1FZE with a full exhaust no cats).

Three runs without the sensors and three runs with.

 

[Howard705]

Open loop/ vs closed loop. It will adjust as needed. reason heaters were added to O2s is for staying in open loop and going in sooner. Im sure better fuel mileage also.

 

[scottryana]

Great answer.

I did not know O2s had the capability to catch errors.

Before I attempt running a aftermarket wideband O2. I am curious to see if my vehicle runs differently with or without the factory O2 sensor. I imagine without getting technical it would be difficult to observe a difference.

So I will be taking it to a dyno jet before an after to see if having an O2 + air temp sensors running will in any way shape or form change the engines performance. It should be interesting. (BTW, bone stock GEN 2 1FZE with a full exhaust no cats).

Three runs without the sensors and three runs with.

This is going to be interesting, because I am not sure your ECU will know what to do with the O2 sensor? I would imagine if it was engineered to run without one adding one would be superfluous. But it is curious to me that you guys don't have an intake temp sensor. The MAF has to have a temp sensor to work. The additional temp sensor you are talking about might be for some other feature. Kind of like how there are 2 coolant temp sensors, 1 for the ECU and 1 for the dash.

 

[ToyotaIsLife]

This is going to be interesting, because I am not sure your ECU will know what to do with the O2 sensor? I would imagine if it was engineered to run without one adding one would be superfluous. But it is curious to me that you guys don't have an intake temp sensor. The MAF has to have a temp sensor to work. The additional temp sensor you are talking about might be for some other feature. Kind of like how there are 2 coolant temp sensors, 1 for the ECU and 1 for the dash.

I am positive that the O2 sensor will be recognized by the ECU. while the 80 series cruisers don't come with O2 sensors here, I failed to mention that all 1998+ FJZ100Ls do come with a catalytic converter and an O2 sensor from the factory. It's just that its rare to find a FJZ100L here with the O2 still installed.

The FJZ100Ls also come with air temp sensors on the factory airbox standard from the factory. Although same as the O2 sensor, it is rare to spot one that still has it installed.

So I am sure both would function to some degree.

We will know for sure by the end of next week.

A picture of what most oxygen sensors look like on FJZ100s here, disconnected with the sensor acting as a plug.

A picture of what most air temp sensors look like, also disconnected lol.

MAF Sensor (on intake manifold)

A picture of the air temp sensor that fits on the airbox.

 

[Kernal]

Is there an unused factory O2 sensor connector (or two) available on your vehicle's engine harness?

 

[dugsgms]

Okay, I'll take a shot at this.

Technically all you really need for EFI to work is engine speed and throttle position, commonly called Alpha-N strategy. Motorcycles used, and in some case still do, this until fairly recently. Above that would be speed density which incorporates a MAP sensor to further add fueling/timing accuracy(mostly for the sake of lower emissions and added fuel economy) and beyond that Mass Air Flow which has the advantage of automatically compensating for altitude and humidity changes. Adding more inputs such a IAT(intake air temp) increase the accuracy and allow them engine to run closer to ideal air/fuel for fuel economy and to a lesser extent power production. Adding a oxygen sensor allows the computer to verify fueling is correct in real time, called closed loop monitoring.

Essentially, what you want is to run as lean as you can for each operating conditions to keep emissions low and power as close to max while keeping things safe for the engine. The more inputs you have the easier it is for the computer to accomplish but that comes at the cost of added complication and failure potential(think of high end German cars, they have a lot of very complicated systems but also suffer from very low reliability because of it, the more parts you have the more potential for things to go wrong).

If I had to guess, I'd say that vehicles spec'd for middle eastern countries there was more of a emphasis on reliability than emissions/fuel economy due to potential operation in very remote areas, the relatively low cost of fuel and the relatively low air pollution problems(or the lack of concern over it). It would also allow for less complicated computers and that would keep costs low by allowing for simpler circuitry and software(no code needed for the the additional sensors or the failure effects management if those sensors fail) as well as simpler wiring and the obvious cost saving from not having the sensors themselves.

 

[IvanFZJ100]

Hi. I have a GCC-spec FZJ100 2002 with 1FZ-FE engine. I have no catalyst, No O2 (lambda) sensor. I have a disconnected Air Temp Sensor near the airbox and I have a MAF sensor. I can't see any wiring for the Air Temp Sensor and O2 sensor. There is only one loose/ empty 6-way connector in the bay area near both sensors. Is it possible this 6-way connector splits into 4-way (O2) en 2-way (air-temp)?

Reason. I need to install a 3-way catalyst with O2 sensor...for registration

My OBD device can't read the toyota-pin so NO IDEA if the ECU can handle the O2 sensor. Reading prior above answers. Are there 2 different ECU's or where all delivered with the same?

Hopefully this thread can help me..

 

[IvanFZJ100]

Additional info: managed to read the OBD. No fault codes, No O2 sensors. My ECU is 89661-60710 (Australia and GCC). For GCC (China, Peru, Saudi) after 2002 there was an other ECU with number 89666-60790.

Also in the attachments the NEW FEATURES that includes a Three-Way catalyst (TWC) for the J100 model with 1FZ-FE engine for Saudi, Peru and China after 2002-08.

Short conclusion: There where 2 models with same engine. One WITH and one WITHOUT O2 sensors. Pre 2002 (GCC and Australia) without and for some after 2002 (GCC) with sensors and TWC. Noticeable that the models after 2002 also have another ECU.

Resume:

* FZJ105 - GCC (general)/ Australia - NO O2 sensors. ECU #89661-60710
* FZJ100 - GCC (general) 1998-2005 - NO O2 sensors. ECU #89661-60710
* FZJ100 - GCC (Saudi, China, Peru) 2002-2006 - O2 sensors. ECU #89666-60790

This could explain why some models have O2 sensors and some don't.

Question(s):
1) Is there someone driving ECU #89661-60710 with sensors?
2) Or are these all models with ECU #89666-60790?

 

[jpoole]

Fun thread and I'd like to hear back from someone that adds a wideband o2 and air/fuel ratio setup on how rich/lean they are running without o2 sensors.

Having lived with FI systems without o2 sensors there are a number of downsides to these in my opinion and only a few benefits. Benefits largely seem to be lower cost to produce and increased simplicity, at least in terms of no o2 sensors which could cause more issues in some areas depending on the range of fuel blends and quality they may see, etc..

For earlier (pre 1FZ) no o2 sensor FI setups my assumption is that on the assembly line after full assembly they would use an exhaust sniffer to detect engine tune and make final adjustments to the air/fuel ratio of the system. I've seen paint marks on the adjustments for some of these early FI systems that indicate these assembly/setup procedures but I'm just speculating. When I've worked on these examples it's been many years after they were built and some have been surprisingly far from a good tune.

The downsides with the no o2 FI systems is that the ones I've worked with don't adapt as well to changing conditions. Major altitude changes, worn or changed engine components, changes to the engine tune, fuel changes, etc. can all impact the final air / fuel ratio and efficiency of an engine and particularly the early FI systems with few monitoring sensors could cause the engine to operate pretty far out of the ideal range leading to excessively lean or rich operation which can cause a lot of damage.

My guess is that by the time the 1FZ came around that the Toyota engineers had some good ideas about triangulating how the engine was doing from a range of sensor inputs to the point where they could compensate for not having an o2 sensor while keeping the engine in a decent operating state. It would be interesting to see exactly what the tuning maps are for the FI and how they weight and respond to various temp and other input signals. A lot can be told about operation efficiency with a few temp sensors and some load calculations I'd guess and if these 1FZ engines without o2s are still typically running well I'm sure Toyota did a good job setting these up though I'd bet they are conservatively tuned.

 

[sjpitts]

Doesn't leaded gas ruin O2 sensors? Maybe Toyota took them out for markets where unleaded gas is not always available, even if the engines would have run better with them and they were not that expensive.

 

[Rifleman]

Doesn't leaded gas ruin O2 sensors?

In a word, Yes, leaded gas ruins O2 sensors,

 

[IvanFZJ100]

If checking the wire diagram of the 2000-2002 J100 it seems Saudi and China had the same ECU (89661-60710) as GCC countries. But GCC is running with VAF and China/ Saudi is running via O2-sensor. The China/Saudi ports on the ECU are also different (marked with a colour).

There are 3 different ECU's for Automatic transmission:

- 1998-2000 = 89661-60680. Wire diagram shows no O2 sensor
- 2000-2002 = 89661-60710. Wire diagram shows with (china/ saudi) and without (gcc) O2 sensor
- 2002-2005 = 89661-60710 and 98666-60690. Wire diagram shows with (china/ saudi/ peru) and without (gcc) O2 sensor

It would be clear as 60680 and 60710 are running without O2 sensor and 60690 running with O2 sensor. i.e. in 2002-2005 there where cars delivered with and without and both ECU's (60710 and 60690) where installed in these cars. But that doesn't explain the series 2000-2002 in comparison with the wire diagram. Also these series where delivered with and without O2 sensor checking the diagram.

The other thing is. Toyota NEW FEATURES states that the TWC+O2 sensor where new features from 2002/08...And not 2000/08 - 2002/07.

Question remains. Is 89661-60710 compatible with O2 sensor?

 

[IvanFZJ100]

News update.

The wire connections in the ECU OEM 89661-60710 in the FZJ100 pre 2002-08 for the O2 sensor (1B and 6A) are already occupied by a RED (speedsensor in 6A) and GREEN wire (SL in 1B to ECT Solenoid).

So:
- wire diagram engine control: 6A and 1B are for HT and OX
- wire diagram ECT and A/T indicator: 6A and 1B are for SP2+ and SL

Bummer