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11

Lambda sensors, often referred to as oxygen sensors or O2 sensors, are the bedrock of any modern-day EFI system. Without them, fuel injection management is essentially flying blind and has to resort to other less-desirable means to determine how much air and fuel need to be mixed. Their primary role is to provide feedback to the fuel management to determine ...


9

It should hold up. It melts at around twice the temperature where water boils, which I don't think you'll ever experience in the engine bay (unless it's touching the exhaust). But the greasiness in the engine may make for a poor adhesion. BTW: I am one of those people who would rather crimp than solder.


8

It was indeed the catalytic converter (the EX does not have a pre-cat). After replacing it, the downstream sensor graph spends most of its time above 0.5 V, as it should if the converter is working. Update: I started getting this error code again, a little over a year after replacing the cat. I also finally found a guide on how to read these graphs, from ...


8

No, you don't have to rely on wire colors to figure out what's what. With nothing more than a decent multimeter and premix flame (blowtorch or gas stove), a two-test sequence can reveal the identity of each wire, assuming the O2 sensor is fully-functional: Determine the heater wires This should be done first. These wires serve to heat up the O2 sensor ...


7

Looking at the description of the California O2 sensor for your car, the only thing different on it (besides the internals) is the electrical plug. The wrench which you tighten it down with is 7/8", which means the sensor bung should be the same size as well. I don't think there is any real external difference between the California and non-California ...


7

This requires a bit of mechanical know-how and some time... An O2 sensor can be tested with a multimeter that measures millivolts. You'll need to securely attach one lead to the signal wire of the sensor and the other to a good ground on the car. This all has to stay in place with the car running... Fire up the engine and look at the voltage reading of ...


7

We found at least two issues The air filter housing wasn't forming a proper seal with the MAF sensor This engine boasts a quirky design where the MAF sensor sits at the back of the engine. The air filter housing seal is in the middle of this first picture, MAF sensor in the second picture (stills were taken from this video). Whoever had installed it ...


6

If you are going to replace the sensor and have already purchased the replacement, cut the wires off of the old sensor and put a 1/2" drive deep well socket onto it (don't use the split socket for the O2 sensor to take it off, but you will use it to put it back on). Use a breaker bar to break it free, then use a ratchet the rest of the way. If you do not ...


6

Pending code? The user manual for your device says it should say "PD" for pending codes, so maybe not. "P0130 P" isn't a valid DTC for your vehicle so pending code is really all that makes sense. More specific to your model P0130 is front oxygen sensor circuit range/performance problem (Lean) Possible causes: Open wire to O2 Sensor Short to ground in O2 ...


6

Your data logs tell me the following: Fuel trims are fine Here are some plots I generated from your data for both short-term and long-term fuel trims. The plot above (Bank 1 STFT vs Bank 2 STFT) show that there is no bank imbalance and most of the data points hover around zero STFT correction, which tells me that feedback from the O2 sensors is ...


5

In the perfect world, you just slide a wrench on the O2 sensor and it comes out. Unfortunately since its located in a "hostile" environment (lots of heat, lots of water and potential corrosion underneath) it typically gets pretty stuck, though most people eventually do have success getting it off. Careful not to start stripping it with that open ended ...


5

Just to add to the other answer as I ran into this same issue, what kind of emissions do I have on my mitsubishi galant? I had this code: P0421 and I had to replace my O2 Sensor & the catalytic converter but I wasn't sure if I needed the CARB (California Air Resource Board) compliant ones or not. There is a label that identifies what type you have. I ...


5

I doubt you're going to be able to have someone put a number on this. I'm betting you also know that just because no error was thrown, it doesn't mean that the sensor isn't impacting performance. Lifehacker notes that replacing them could improve mileage "up to 15%." As @BobCross mentioned, "most people wouldn't consider it worth their time to do the ...


5

It is most likely that this sensor has failed. The question is why does the MIL only come on above 70mph. The answer lies not in the sensor but how and when the sensor is tested by the PCM. Every sensor (and actuator) in the engine control system is tested by the software, but not all the time. Each sensor has its own set of test entry conditions; each OEM ...


5

Check fuse 21 in the under hood fuse box. If the fuse is OK at one of the o2 sensors check for power on the red/yellow wire. If you have no power at the o2 sensor I'm afraid your going to be looking for a short to ground. Which would involve tracing the wiring harness and visually inspecting for rub through or broken wiring.


5

You may want to review this answer of mine. The tests outlined there for heater resistor continuity and response to lean/rich conditions assume a fully functional sensor. If the behavior under testing doesn't match what is outlined there, you know that the sensor has an issue.


4

Buy the correct O2 sensor, hacking up the OEM harness to put a different O2 sensor on the car is a bad idea.


4

The ECU may have "tuned" itself to the gap and behavior of the old plugs. When you had the plugs replaced, if the shop did not disconnect the battery (and even if they did, not sure about your Ford) the ECU would still have the long term fuel trims that matched your old plugs in effect. So this may result in a bit less or more fuel being injected and ...


4

With the check engine light on, the car is going to be running a fixed set of parameters from the Engine Control Module. For instance Fuel Pressure will be held at max pressure and timing and spark adjustments (if done electronically) will not retard or advance. One of the reasons this happens is because the Engine Control Module is not recieving all of ...


4

From time to time you do come across a rusted in sensor. Your vehicle being a 2001, and O2 sensors lasting some time, yours is rusted in. If sheer force does not work you may need to use an oxy-acetalyne torch on the sensor to heat to it red-hot to break the rusting and undo it with a good single-hex deep socket. I have had one or two sensors break up and ...


4

As @LynnCrumbling stated, this would be hard to put a number on, mainly because it depends on too many factors. This is what I can tell you. When O2 sensors get old, they don't necessarily go bad, what they do is get lazy. When a good O2 sensor is doing its thing, if you were to look at the readings from it, the numbers go all over the place, from top of the ...


4

Disconnect your battery to reset your ECU. It won't hurt, and is probably the cheapest and easiest thing you can try. 30 minutes is usually enough. There are other theories as to why your mileage went down, but I think you're on the right track thinking the ECU hasn't learned to use the new data correctly. I am thinking that because your new 02 sensor is ...


4

If the catalytic convertor is truly plugged, you wouldn't be able to drive the vehicle, so this makes me wonder about the voracity of your statement. With a plugged cat, the back pressure created behind it will only let you rev the engine to around 1500-2000 rpm. I had to replace a set of heads on a pick-up truck for a guy because he continued to run the ...


4

Root Cause: probably a couple of things Sadly, I feel that there isn't enough data here to uncover the smoking gun, but I have realized some things upon reflection that can indicate what is probably wrong with the vehicle: Question 1 If the front lambda sensor voltage is indicating rich, why is the fuel trim positive (indicating that the injector ...


4

The Red/Yellow wire is in the harness, not on the O2 sensor. It's can only be something that effects all 4 sensors. The ground is provided individually for each sensor by the PCM so it can't be on the ground side. Power is provided by Fuse 21, but that also powers the EVAP canister vent valve so if that fuse was blown it would also set an EVAP code, but ...


4

Bad O2 sensors can contribute extra heat to the system, but usually they have the opposite effect. When the ECU detects that the sensors are faulty, the engine will default to open-loop mode, which should cause a properly functioning engine to run a rich A/F ratio. This actually has the effect of cooling the combustion charge and removing more heat from ...


4

The upstream o2 on a Prius is an AFR sensor stoich reading at idle is 3.33 volts. The application isn't able to read the correct PID. So of course it would read 0v all the time.


4

TLDR: The sensor is difficult to check because the current change it produces is too small for most clamp meters, so you would have to cut the harness to test it. Not recommended. Try checking for bad connections first. If it's not those, and it's likely not the ECM as you would likely have other symptoms than just this, then try replacing the sensor itself. ...


4

Excellent graphs. The after catalyst sensor shows normal mixture readings. The PCM can and will operate the system lean or rich depending on operating conditions. The voltage will rarely be held at any intermediate voltage, such as 0.5 volt. This is an urban legend not based on engineering fact. The rear sensor voltage should remain steady at any steady ...


3

Also, remember that MAF is a reading of the amount of air entering the engine. If you have a backflow issues (high backpressure) or even a timing issue where the valves are not opening and closing at the correct time (slack chains, jumped timing), your MAF sensor readings will reflect this as well. I know this post is late, but any who are looking into this ...



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