Does this car have an O2 Sensor?

Hello, for 2002 service info is showing a 1.7liter engine, and quite a few different engine setups, a DX, EX, GX, HX, LX, there should be a tag on the vehicle somewhere or in the owner's manual in the glovebox as to what version it is, and this does effect the Oxygen sensors. They all have at least 2 Oxygen sensors, some of these different models have a front A/F ratio sensor (air/fuel ratio sensor) that is in front of the Catalytic Converter, it acts somewhat like an Oxygen sensor but is a more advanced wider range sensor. That cannot be interchanged with a regular 02 sensor.

Okay, so looking through service info a little more, the DX is the only 1.7 liter, but there are many variations for this year for some reason, any Oxygen sensors you should see screwed into the exhaust pipe, with a 4 wire connector, on a 1.7 liter engine there will most likely be a front oxygen sensor in the exhaust manifold, but they should all be visible sticking out of the side of the exhaust system all the way down passed the Catalytic Converter.
Here's some examples of the front and rear sensors.

Are there emissions testing in your state?

Is there any sensors in the entire exhaust pipe, even after the Catalytic Converter? (The larger sections of exhaust pipe). Im not really sure how or why there would be any oxygen sensors missing from the vehicle. You're in the US correct? Or not?

In 2002 they did build a model with no Oxygen sensors, I was surprised to see it, but if you're not in the US, it's different requirements here. We have very strict laws on emissions here. I can imagine without any air/fuel feedback systems in place, it would be more difficult to diagnose rich or lean running conditions. Usually there would be one 02 in front of the Catalytic converter and one behind it to monitor its performance. And set trouble codes for emissions related problems.

No, what I mean by monitoring the air/fuel ratio (mix), is having an actual feedback sensor like an Oxygen sensor in the exhaust pipe that can read whether the air to fuel mix is within an acceptable range. The Oxygen sensor will tell the engine computer (ECM), (for example) if the exhaust gases coming out of the engine are too lean, meaning not there's not enough gas getting into the engine, the ECM can adjust the fuel injectors to add more fuel to the mixture. If on the other hand, the mixture is too rich, meaning there is too much fuel being read in the exhaust gases, the ECM can then re-adjust the fuel injectors to take away a little fuel to get the air/fuel mixture to where it should be. With no feedback sensors, like an oxygen sensor, the ECM has no way of knowing what the mixture is and just runs the engine on a preprogrammed, basically default fuel strategy.

I've never run into a vehicle that did not have Oxygen sensors, I've been working in the automotive industry for almost 25 years, and here in the US every vehicle has to have Oxygen sensors, and starting in 1996, we went to an even newer more restrictive emissions system called OBD2, which has even higher standards and more laws regarding emissions testing.

After a little searching I have come across some others mentioning they can't find any 02 sensors on their 2002 Civics built in the Philippines. Very surprising to say the least. Apparently, the engine is run so lean the vehicle does not even have a Catalytic Converter. This is programmed into whatever is controlling the fuel injectors, so they much just run at some base pulse width (On/Off time). I would expect them to put at least one 02 in the exhaust up front to prevent damage to the engine from running too lean or too rich. Running too lean will cause the cylinders to get extremely hot and cause possible mechanical damage. Running too rich will cause excessive carbon to build up inside the cylinders, which in turn, causes pre-ignition or detonation. This can burn holes in the intake valves because the air/fuel mixture starts to ignite even before the intake valve is closed. You can have back firing into the intake manifold, or into the exhaust.

So, I take it you are having some kind of running problem, can you describe what is happening? And if the problem is better or worse when the engine is at a cold start up or up to operating temperature?
Something you can do, (but I'm not 100% sure), if your mechanic has a scan tool, he can check the engine computer for any possible stored trouble codes, (again I don't know how these ECMs are programmed and what they can or cannot do). Here is a guide that can at least explain why the Check engine light would come on:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Or if you can give a very good description of what is happening, we can give you some testing to do. But it will be very basic testing since we may not have any scan tool data to go by. Honestly, I cannot see a vehicle with no fuel control to last very long. But if you have a lack of power or feel the engine shaking while idling either in Park or Drive with your foot on the brake pedal, you may have cylinders misfiring, in which you can check for good spark at each spark plug wire, and each spark plug itself.
You can do compression testing on each cylinder to make sure they are all equal and not too low.
You can check fuel pressure for any vacuum leaks which would cause the engine to run even leaner, vacuum leaks can happen from a bad intake manifold gasket, or broken hoses that go to the engine. I will post some more guides for you to read since this is a very specific case study and very rare.
Sorry for my long post, but this is a unique situation.

Check out these guides, and let us know what the vehicle is doing, and we will do our best to try to help:

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/mass-air-flow-service

https://www.2carpros.com/articles/engine-has-low-power-output

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

If it's consuming too much fuel, you could pull the fuel rail, leave the fuel injectors in the rail and prime the fuel pump, by turning the key On, and check to see if the fuel injectors are dripping any gas out,
Another possibility is that the MAF is over reporting air flow, so sending a signal to the ECM that more air is flowing than actually is, the ECM would then add more fuel by increasing the fuel injector pulse width, that's just keeping the injector open for a longer period of time. The only way to know if the MAF is over reporting would be to look at live scan tool data and see what the actual number is. It should read in grams per second.

This engine might have a MAP sensor as well which measures the intake manifold pressure to calculate injector flow, Honda sometimes had both MAF and MAP sensors on some vehicles, but with this one service information is almost impossible to tell what it has and doesn't have.
I'd say, try cleaning the MAF but when a MAF gets dirty it tends to underreport air flow.
Something to keep in mind is Honda is one of the manufacturers that make intake and exhaust valve adjustment possible and it's a required service, they go out of adjustment after so much time. And requires it to be adjusted when the engine is cold. Search YouTube for Honda valve adjustment and you should see many videos on it, the metal noise you're hearing could be anything really though.

When you turn the key On the fuel pump should run and prime the fuel rail for about 2 seconds then shut off, the fuel injectors should not drip any gasoline, they should hold the fuel pressure that was just primed by the pump.

For the MAF (mass air flow sensor) a rule of thumb that we use is more for larger engines V6 and V8 type, which is the liters of the engine size, so for example a 5.0 liter engine we would expect to see 5-7 grams per second at idle. For a 1.7 liter, roughly 3-4 grams per second at idle (g/s). The idle rpm should be around 650-700rpm, if it has a high idle when its fully warmed up there might be vacuum leak into the intake manifold, either by the intake manifold gasket or broken vacuum line/hose somewhere. Hondas tend to have a hunting effect when they have a vacuum leak, so the idle will be up and down effect because the engine computer is trying to compensate back and forth for a leak, and they have more trouble settling for a stable idle then other manufacturers.

The difficult part about this vehicle is not having the oxygen sensors for a feedback, in many cases we would look at a data PID called the Long Term and Short Term Fuel Trim, Im not sure how that data PID number would even show up on this vehicle, the Fuel Trim should be as close to zero (0) as possible, if that number was +15% for example, that means the engine computer is adding 15% to the air/fuel mixture to compensate for additional air coming in somewhere. And the oxygen sensor would read that excessive air, report it to the engine computer (ECM) and it reacts, if the Fuel Trim numbers were -15% then the ECM is taking away fuel from an overly rich mixture (too much fuel), that can be caused by leaking injectors, MAF that is under reporting air flow, etc.

If you are able to scroll through the live engine data on a scan tool, look for LTFT or STFT, the MAF reading, RPM, etc. The Long Term is a learned value and the Short Term is the compensation the engine is making constantly. After so much time the engine computer should learn values of the sensors, and on newer vehicles in many cases it can even compensate for faulty sensors by using known good learned values, or numbers. That can be a tricky part sometimes. Make sure you dont have any fuel leaks as well when the car is running.
So if you notice you are using more fuel than you think it should, then it sounds like the ECM is adding fuel for some reason, from what Ive read on this model the engine comes pre-programmed to run leaner than normal, which is odd to me, but this is a rare case for sure. I will have to do some more research on how the ECM might be programmed to get a better idea of its fuel strategy. Below are some guides to help understand a rich and lean running engine a little better.

https://www.2carpros.com/articles/why-an-automotive-engine-will-run-rich

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers