16

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 to ...


12

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 ...


11

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

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 ...


8

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 ...


8

Most vehicles which are OBD-II compliant (newer vehicles are a little different) use just the O2 sensors located before the cat to adjust the air/fuel ratios. The in-cat or after-cat O2 sensors are just used to check the efficiency of the cat itself. Therefore, in most modern vehicles a car can run just fine without a cat. Please note, this is not to say ...


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 sensor....


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 didn'...


7

Picture 1 is the downstream 02 sensor. Upstream is located on the exhaust manifold. Picture 1 contains both convertors. Picture 2 is the exhaust resonator.


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

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 ...


6

The 50 g/s max flow reading that you are getting is far lower than what merely altitude can explain. The chart above shows that at about 5,200 ft above sea level, the density of air is 83% of what it is at sea level (0.062 lb/cu.ft vs. .075 lb/cu.ft). So to account for the altitude, you should multiply your expected mass flow by 0.83. According to the VAG-...


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

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 ...


6

If they told you the truth and unsuccessfully tried an acetylene burner: Well, yes: What does not get loose with such measures will (most likely) damage the thread (if that not already happened) if you force the sensor out. I personally would go that path: Soak the thread with penetrating fluid and buy a matching helicoil/thread-repair kit. When you feel ...


6

This is a bad idea. There's a very good reason why ECU's default to running on the rich side when they are unable to get a valid reading from the O2 sensor and that is because running an engine too lean can cause quite substantial amounts of damage. If you were able to (somehow) simulate the fluctuating readings within the "acceptable" range the ECU ...


5

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 ...


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

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 pulse-...


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

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.


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.


5

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 ...


5

Upstream Variation (Hz) is also called O2 crosscounts, this normal fuel mixture control, the fuel computer changes mixture ever so slightly so it crosses the stoichiometric boundary (.45v), back and forth from lean to rich. The more crosscounts the better fuel control is and indication of a healthy O2 sensor, high crosscounts is also an indication the fuel ...


5

Here's how to decipher INPA lambdaintegrator Short-term fuel trim. Both banks have a short-term correction of 28%. This should settle down to 0% fairly quickly, so the fact that it stays red indicates that it is attempting to apply the maximum possible correction for a lean condition (and failing to bring it within spec). adaption value additiv This is ...


5

Which sensor was removed? Pre- or post-cat? If pre-cat, it could be causing the engine to run differently. If post-cat, it's just noise and your engine shouldn't be running any differently ... it just sounds that way. For most cars (and I'd bet your Volvo is one of them), the after cat O2 sensor does nothing for the running of the engine, it just checks for ...


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

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


Only top voted, non community-wiki answers of a minimum length are eligible