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4

Before suspecting a bad O2 sensor... You need to be sure that the replacement MAF is suitable for your car. You mention the replacement MAF is a 5-pin and not a 4-pin like the one originally on the car. If the new sensor has a different flow-voltage calibration this would go a long way to explain what you are seeing. This is because the onboard fuel ...


3

It sounds a lot to me like it could be your car's O2 (lambda) sensor in the exhaust. From wikipedia Oxygen sensor Function of a lambda probe Lambda probes are used to reduce vehicle emissions by ensuring that engines burn their fuel efficiently and cleanly Sensor failures Normally, the lifetime of an unheated sensor is about 30,000 to ...


2

In answer to your last question, yes your car does have an o2 sensor, all modern cars do. Here are a few tips to pass an emissions test Drive the car on the freeway for at least 20 minutes before taking it in to get the emissions tested. If the engine is cool when you bring it in it won't burn as clean. Get a tune up. Replace the spark plugs, wires, and ...


0

In addition to Bob's sock puppet's O2 socket and crow's foot suggestion, I'd like to add that O2 sensors are usually size 22 mm. In a pinch, a 22 mm spanner/wrench with enough leverage will also do the job. It helps to soak the threads in rust solvent prior to removal.


0

P0100 A code P0100 may mean that one or more of the following has happened: The MAF may be disconnected, or a wiring connection may be bad The MAF sensor may be faulty If the MAF sensor element is dirty use disc brake cleaner. Do not use Throttle body cleaner because it will leave a residue that will muck up the sensor. A residue on the hot wire element ...


5

It should look something like the following picture. The flats for the wrench are at the bottom so you may not be able to see them depending on the location. They also might be covered by a heat shield. You use something like the tools pictured below to get it off.


1

Your graphs look very normal. No, the post cat sensor will remain a nearly flat line when the engine is a steady speed, if the catalyst is good. It can and likely will lean or rich as the PCM chooses its fuel control strategy. So steady voltages of .2 to .8 are normal. The catalyst acts as a homogenizer of fuel mixture so the rich to lean cycling seen ...


0

I think it very much depends on the ECU you are using. On early Volkswagen systems, they feature a pre and post cat lambda probe in the US as this is mandated but only set mixture based on the pre cat probe. Makes sense I guess as the post cat probe won't tell you much if the cat is working correctly. In the UK we don't have check engine lights so a probe ...


2

Both pre and post catalyst "Oxygen" Sensors report exhaust fuel mixture to the PCM. So the PCM can and does use both to sense and adjust mixture. The rear sensor gives a better average mixture because the catalyst is a mixing chamber. In newer designs the rear sensor is used more for mixture sensing than the pre-cat sensor. In these designs a pre-cat Air ...


3

As @FredWilson pointed out, there is no relearn for a heater circuit code. On a 2.3 Check for power at the ECM connector C pin 13 (white). On a 3.0 Check for power at the ECM connector C pin 1 (black/white). While the o2 heater wire may have power there may be a break in the wire that goes to the ECM. This wire tells the ECM that the heater relay is ...


0

This is gas cap check valve. I tried to edit my post but It would let me. So here is a follow up for clarification. The check valve in the gas cap helps to regulate the pressure in the EVAP system.


0

Milan, I recommend that you purchase a paper Chilton's or Haynes repair manual for your car. They cost around $30 at your local autoparts store. Many manufacturers have provided a 'secret' code that you can use to turn your check engine light into a blinking code reader. The instructions for that tend to be written in the repair manual (not all ...


0

Regarding the whooshing sound when you remove the gas cap. This could be a defective gas cap check valve. The check valve performs 2 functions. When the fuel pump takes fuel from the tank the fuel volume decreases creating a partial vacuum inside the tank causing the fuel pump to work harder. The check valve injects outside air in to equalize the pressure ...


4

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 ...


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.



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