DataLog

89 000 Everything is still in good condition, after 10 000km coolant level didn't change and oil level didn't change.

I'm using KW850 and it allows me to see everything I need at the moment. My check engine did turn on after a few trips, but not immediately. I cleared it with my scan tool lol. (it will probably pop up again) I am still keeping the EGR disconnected, just to check what will happen with fuel economy. I will post an update after 100-150km As I have mentioned in the comment above, I will do everything that is in my power to try to reduce fuel consumption. If that leads to some power increase by mistake, it will just be another plus. The only thing I will not tolerate in this pursuit is power decrease.

I am not aiming for power as much as I'm aiming for fuel efficiency. The only way I would've expected better fuel economy from deleted EGR valve would be due to different driving style. As I have mentioned above, I did not feel or test any significant difference. My goal with cold air intake is primarily (and everything I'm trying right now) is mainly fuel efficiency. On the topic of remapping, this engine in stock condition can go safely up to 70hp. Which to me is not insignificant (almost 10%). I have no experience in programming vehicle ECU-s, but I do have experience in programming chips. After I try every physical modification, I will start playing with the ECU. I'll open a topic on increasing AZQ engine fuel efficiency, so that we have everything in one place. I will also be testing everything stock and after the modification to see if there is any measurable difference.

I forgot to mention that temperature drop with EGR disconnected was pretty insignificant. It dropped from 37C to 34C and that makes sense to me, because EGR only really needs to add a few % of total volume into the mixture because air is already 80% inert. (although it was much colder outside when I tested 37C) I will keep tracking the intake temperature, because my next test will be a big cold air intake. First I will put it like a noob without any insulation just to see what's the difference, then I will make a proper box for it and reroute the air from the front.

Cool, I will look into it. I'm actually pretty happy about the car, it's running really well. I just wanted to see if I'm missing on something by having EGR valve connected. Today I have tested it and I haven't seen any noticeable effect. Maybe it helps people who have damaged or clogged valve. When I see the hype with so many controversial opinions, I see no other option but to really test it and record the data. My only complaint is idle, and I don't think anything is wrong with the engine but I personally dislike it. When the engine is not yet 100% warmed up, it idles at about 800-810 rpm (this is after the initial 1000rpm cold). The idle at 810rpm is very nice and I like it. But after a while it drops to 750-760 and to me it just seems like it needs this 40rpm more to operate smoothly. It doesn't stall, but It doesn't feel quite smooth. Does VCDS allow me to set the idle rev range? I don't really need another diagnostic tool because mine is quite decent. But it can't program the ECU.

But there is one problem with the EGR regardless of it's net effect and that is responsiveness. It takes a second or two for the gasses to clear even if the EGR is suddenly closed by the computer. I don't think that disconnecting it will improve fuel efficiency, but I do think that a resulting style of driving could.

Yes, I know that. I just don't really trust the old software. That's why I'm going to test it myself and see. I will also track the air temperature (however I'm not sure if the temperature sensor is aware of the EGR) .

Idling and mid range power, and hopefully as a result, a lower fuel consumption. EGR is apparently closed only when you give full throttle and just before stalling. I want to be able to cruise at 3000rpm with still some decent power to it. I don't want to bash my accelerator to the floor (to force the valve to close) every time I want to accelerate. It really depends on the engine, and how well the system operates. I wouldn't do it on a newer vehicle, but my gut is telling me that these cars are not tuned very well, and they rely too much on unburnt gasoline too much for cooling down the exhaust. I think that gasoline pollution is much worse than some extra NOx gasses, but we can't argue with the clueless people who make the regulations. It makes sense for diesels because the amount of NOx can literally burn your lungs in the city. But I've never seen a gasoline engine with those amounts of NOx gasses. As a greenhouse gas, I don't consider it to be worse than dumping raw gasoline into the atmosphere.

Anyways... I decided to disconnect the EGR connector to the ECU. I left it stuck on the valve, It's just not clicked into place (so I could easily click it if necessary). On my Fabia it didn't trip the check engine light, but my scan tool detected the code. Since I don't really care about the code, I will leave it disconnected for a while to see how much improvement I'll get. I will plug it back in before the emissions test lol.

No, I didn't check it. I'm pretty new to actually fiddling with a car, although I did read my fair share about the engines. In the link I mentioned, they did claim that there is an oil level sensor. Maybe that's just plugged in Skoda. This is a WV article and it's about AZQ engine in general (both 6V and 12V).

I saw that some EGR valves cool the exhaust, although it didn't specify if they use clean air to do it or some kind of liquid cooling. I would say it's just sucking the air in to cool the valve in this case. I don't like the fact that it is so hard to get the exact datasheet on each of these parts.

I can't seem to find explanation as to why is there a hose connected to my air intake (1.2 12V Fabia MK1 engine). From what I've seen EGR valve on this engine is a computer operated solenoid, so it doesn't require a vacuum hose. Why does it require a connection with airbox? Is there a some kind of sensor within the valve? What would happen if it were disconnected?

I recommend you read this: http://pierro777.free.fr/DOCVAG/SSP260_The 1.2Ltr 3 cylinder petrol engines.pdf It has all the information about 1.2 engine, list of all the sensors and how the ECU determines what it does. Your engine does indeed have the oil level sensor. I have the same problem as you. In 3 days I will check with my friend what's going on when I change the oil.

I'm from Croatia, a Skoda Fabia MK1 (6Y6) owner. Professionally a chemist, but I'm keen to programming microcontrollers (EPROM chips, and platforms like Arduino, NodeMCU, Raspberry Pi) and am mechanically inclined. One day I may even start fiddling with Skoda computers and after I figure it out, I may even create my own chips that would simplify tuning. My biggest hobby is system optimization. Since I'm a chemist, I have many alternatives as to which chemicals to use when cleaning sensitive things or modifying combustion without breaking your bank.