P0171 with Landtank's MAF

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Ok great that is what I have as well.

Good, what I've been told is that the newer sensor goes through a cleaning cycle where it elevates the hot wire temp during startup to help remove debris from the last driving cycle during cold startup of the engine.

If Joey has the 07010 he should change it out. And if it came from me he needs to contact me about it.
 
Good, what I've been told is that the newer sensor goes through a cleaning cycle where it elevates the hot wire temp during startup to help remove debris from the last driving cycle during cold startup of the engine.

If Joey has the 07010 he should change it out. And if it came from me he needs to contact me about it.

Dammit! But mine is running so nice :(
 
If Joey has the 07010 he should change it out. And if it came from me he needs to contact me about it.

It did not come from you, I got it from EBay. But I just checked 6 threads that has the same part number, in fact it replaces 22204-21010 (same as 2204-07010).


But according to my pinouts, its not the same.
 
Were your wires on the plug set the same as the directions? Now I am really curious what info your truck was getting from the sensor compared to a stock housing and sensor. Maybe you were giving the computer a zero voltage all the time and it was running lean, hence the power increase you felt? Total WAG but I am actually kind of surprised it would run if the wires and pins in the plug did not match the actual sensor.
 
Were your wires on the plug set the same as the directions? Now I am really curious what info your truck was getting from the sensor compared to a stock housing and sensor. Maybe you were giving the computer a zero voltage all the time and it was running lean, hence the power increase you felt? Total WAG but I am actually kind of surprised it would run if the wires and pins in the plug did not match the actual sensor.

Same wiring directions.

Pretty sure I'm not running lean or else I would be plagued by CELs. Plus I usually have a gas smell in exhaust.
 
Pretty sure I'm not running lean or else I would be plagued by CELs. Plus I usually have a gas smell in exhaust.

How does this work? You are pretty sure you are not running lean, yet you are getting a lean code? Of was this last time the check engine light came on, not code P0171?

What is your actual long term fuel trims? Those should indicate if you are running lean or not.
 
How does this work? You are pretty sure you are not running lean, yet you are getting a lean code? Of was this last time the check engine light came on, not code P0171?

What is your actual long term fuel trims? Those should indicate if you are running lean or not.

seriously, it's come to harassing members?
 
seriously, it's come to harassing members?


Why is it harrasing? P0171 is a lean code. Yet the post says it is not running lean. That is why I asked.

The code is post combustion based on what the O2 see. Why would one get that of it is not running lean. Yet Joey said it I'd running rich.

Maybe I should not have used the phrase "How does that work" didn't mean that in a negative way.

Christo
 
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you need to consult your toyota techs to get the low down. The code doesn't indicate that the engine is running lean.

Well it sort of does, but its based on the oxy sensor, so if unmetered air is injested, it will trigger a CEL for lean, so it could mean the engine is not running lean, technically, but without testing it, it hards to say and be definitive.

Thats what the fuel trims are for, look forward to seeing what they are.
 
go talk to the gurus back in your shop.

I don't need to and I don't play with words. You are trying to skirt the issue. Yes, the there is too much O2 in the exhaust stream. So, the only thing that could be causing it that would not have the motor run lean is a air leak in the exhaust that could let O2 get in the exhaust post combustion. Any leak pre MAF will be accounted for in the MAF reading, any leak post MAF before combustion can cause it to run lean.

However in the case the motor was just rebuilt and if I recall correctly they checked a bunch of system and came up empty. I would assume all the system were checked.

So - as copied from techinfo.toyota.com

P0171

P0174

"When air fuel ratio feedback is stable after warming up engine, fuel trim is considerably in error on LEAN side (2 trip detection logic)"

So, failing any of these systems being faulty, what is going on to cause the code? Smelling fuel in the exhaust is not a check for anything.

Air induction system
Injector blockage
Mass Air Flow (MAF) meter
Engine Coolant Temperature (ECT) sensor
Fuel pressure
Gas leakage in exhaust system
Open or short in Air Fuel Ratio (A/F) sensor (bank 1, 2 sensor 1) circuit
Air Fuel Ratio (A/F) sensor (bank 1, 2 sensor 1)
Air Fuel Ratio (A/F) sensor heater (bank 1, 2 sensor 1)
A/F relay
A/F sensor heater and A/F relay circuit
Ventilation valve and hose
Ventilation hose connection
ECM

So if the truck is not running lean according to you, what is causing it then?
 
Well it sort of does, but its based on the oxy sensor, so if unmetered air is injested, it will trigger a CEL for lean, so it could mean the engine is not running lean, technically, but without testing it, it hards to say and be definitive.

Thats what the fuel trims are for, look forward to seeing what they are.

what it points to is a situation where the LTFT has crossed a threshold (20%+/-) which would indicate that a component or components could produce a lean condition gone unchecked.

In this case a used outdated sensor bought off of EBAY needs to be cleaned on a regular basis to avoid the error.

In no way does it indicate a lean running engine, just the potential of one if not repaired.

This error is WARNING the operator of a potential problem before there is one. Toyota encoded many safe guards into their ECU and this is just one of them.
 
I don't need to and I don't play with words. You are trying to skirt the issue. Yes, the there is too much O2 in the exhaust stream. So, the only thing that could be causing it that would not have the motor run lean is a air leak in the exhaust that could let O2 get in the exhaust post combustion. Any leak pre MAF will be accounted for in the MAF reading, any leak post MAF before combustion can cause it to run lean.

However in the case the motor was just rebuilt and if I recall correctly they checked a bunch of system and came up empty. I would assume all the system were checked.

So - as copied from techinfo.toyota.com

P0171

P0174

"When air fuel ratio feedback is stable after warming up engine, fuel trim is considerably in error on LEAN side (2 trip detection logic)"

So, failing any of these systems being faulty, what is going on to cause the code? Smelling fuel in the exhaust is not a check for anything.

Air induction system
Injector blockage
Mass Air Flow (MAF) meter
Engine Coolant Temperature (ECT) sensor
Fuel pressure
Gas leakage in exhaust system
Open or short in Air Fuel Ratio (A/F) sensor (bank 1, 2 sensor 1) circuit
Air Fuel Ratio (A/F) sensor (bank 1, 2 sensor 1)
Air Fuel Ratio (A/F) sensor heater (bank 1, 2 sensor 1)
A/F relay
A/F sensor heater and A/F relay circuit
Ventilation valve and hose
Ventilation hose connection
ECM

So if the truck is not running lean according to you, what is causing it then?


It has nothing to do with how much oxygen is in the stream. You simply don't know what you are talking about.
 
Actually the threshold is 35%. (Correction +30% to -35% for a 1997 1FZFE) So what that light is for is that the LTFT has been over 35% for quite some time and it is out of spec. So if the truck is not running lean, what is the reason why the LTFT is over 35%? Guess what the truck is running lean, we need to add fuel. While the LTFT is adjusting, the truck is not technically running lean, but something is not correct that is causing the truck to excessively introduce more fuel.

It is not a warning that is is going to run lean. It is running lean already and they consider 35% out of spec to address the situation.

[ADDED EDIT] Clarification on the above statement. Yes, Rich and I might have a different wording for this. It does not mean that the truck is running 35% lean. It means that it is continuously adding 35% fuel ABOVE NORMAL and "ABOVE NORMAL" is the key. In the ideal world, the LTFT would be zero, however due to sensor deterioration and contamination and environmental conditions it will never be zero. Normal is about 10% or so for our altitude. So when we see a LTFT of 30% we say that the "motor is running lean", which it is, but the feedback system is trying to get it back in check. Knocking at this point, maybe / maybe not, but even without a check engine light (the final warning) we would investigate the system and determine why it is out of whack.

What amazes me is that Rick suggest that you rely on a 150k old O2 sensor (that is really very inaccurate and has been replaced with AIR FUEL (A/F) sensors) to keep everything in check, yet you have to regularly clean your MAF sensor. I have seen 1FZFE's run with 250k mile old MAF sensors that have never been cleaned and they don't create these issues. In 11 years of business we have never replaced a MAF sensor due to failure in the shop. We have however replaced a bunch of O2 sensors.
 
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