TitusM

And what are your stats now after new maf?

Where do you have this consumption? How much does it consume when driving out of the city. In my case I can say that I fixed lots of stuff that were wrong with the car. Unfortunately the consumption is not one of them:)). But I do have much better idle and no more leaks and the car is much more fun to drive. In your case - as far as i know polo is common rail. It is a non PD. Tehnically the next generation after lupo and audi 3l BUT the body is not the same. VW did not invest as much in bodywork anymore. My stats over all are 6.5-7 L/100km city and 4.4l/100Km outside/highway (usually city with the car almost empty and outside with the kids and wife so maybe around 120kg extra). I do own a vcds diagnose - without it is impossible to start somewhere(maybe vacuum leaks and other small checks). In your case I would start with the steps below: Usually with any car I start with (injectors and turbo are the last ones): 1)any visible leaks -- vacuum leaks -- and here I include N75 solenoid that moves the turbo vanes The easiest way to check this is with a hand vacuum pump (i bought a cheap one) with a meter on it. You pump and see the vacuum stays the same and also check each vacuum line - turbo, brakes, egr for leaks. To check the N75 solenoid I used a vacuum meter that I connected to the N75 output and i waw that the vacuum was not stable when idling. After fixing it I got less turbo lag. Lately i got a smoke machine from aliexpress. I fixed quite some issues with it(i did not know i had before it on the air intake side). The intake leaks fixed the lag quite a lot. 2)MAF -- in vcds engine -- see if when the engine runs the readings are moving and are in a reasonable area. This is usually one of the reasons vw's consume a lot. 3)lambda sensor if the engine has it. Euro 4+ usually have it. My 1.2 does not have lambda or nox sensor. You can check this if you look at the exhaust. If there is no sensor on it..than there is no nox/lambda sensor:)). Polo for sure has the sensor (maybe even 2 sensors one before and one after the catalytic converter) 4)check for any fuel leaks / even perforated filter hoses, fuel tank. Usually this type of leaks do not register on the car dash so you would catch those only if you calculate full/full. 5)check for stuck rear brakes but that usually is very easy because the rear rims get very hot if the case. 6)the last checks would be injectors and turbo. (also turbo leaks). In my case the injector deviation was fine until I changed the vacuum/tandem pump. After longer Idle there was "white" smoke. The high pressure pump was inserting oil into the fuel. After changing the tandem pump the car would idle better but when looking with vcds i noticed the injector deviation being greater (maybe the injectors were not as lubed with oil as before:)) ) What you have to take into considerations is that NONE of my cars consume "well". I owned: 1,2 tdi, 1.4 tdi, 1.6 tdi, 2.0 and hybrid gte. Each of them had their own particularities and i learned a lot about what causes consumption. I did not get as far as i got with the 1.2 tdi. This is the one I experienced a lot with and that I invested the most and learned a lot about diy diagnose. They tell me I drive quite aggressively so i assume at least 10 ,20% of consumption is my right foot.

Hi, Mine is euro3 so it does not have it. I checked. For now I believe the issue is one of the injectors (it was not visible until I changed the tandem/vacuum pump). The deviation is ~0.7 on one injector compared to the others. I read somewhere that on 1.2 the deviation is much smaller and 0.3 deviation might be an issue already. Since mine is 0.5 from 0 and 0.7 from the other injectors i declare it ...an issue:)). I will keep you posted. In September i will take the care to an expert shop for the gearbox and i will ask them to send the injectors and turbo for revision. I tested 2 other maf sensors - one pierburg and another miele and both of them give bad readings and even worse mileage. For now the original bosh maf seems to be the best (even on vcds the other ones give higher number when idle ~10% but when accelerating it drops very much compared to bosh).

yes:))) in the city.... And I am starting to believe that my driving style and the geography has a lot to do with it. When i get home i have to go uphill for 9KM. It is a demanding hill that asks a lot from the car (I drive usually full power). Outside the city the best I got so far is 4.4 l/100km.

Update: After fixing the air leaks the car runs better BUT 2 months into it and the consumption is again around 6.5l/100KM. I changed the tandem pump (high pressure/vacuum pump) since i suspected it for being a bit old. Replaced it with a pierburg one because i like the design better. The car idles much better now. It is not so rattly when idle. BUT...the consumption is the same. What I noticed is that in VCDS the injectors deviation is different now. One of the injectors is +0.5 and the others -0.2. I guess the problem might have been a bad injector all along but the old tandem pump hid this very well. What is next: I found a guy in my country that does all the gearbox -- bearings replaced, all pump o-rings replaced, hydraulic actuator upgrade. I will take the car there and ask them to take out the injectors and turbo and send it to testing. The turbo seems to have a little play so maybe there is some lack of power there too although it does not show on VCDS.

Sory I tought I answered your question. The total contact on the road is the same as for ecopias (because of the way the threads are built). Maybe ecopias have bigger contact surface (if we take into consideration what off-road drivers say). After a while i am back to same consumption of 6.5l/100. So tires have veeery little influence in my case. The tires i use now are falcon sincera ecorun. If you look at the threads you will understand what i mean -- much bigger distance between longitudinal threads.

6E0601025F They are...quite hard to find. Lupo 1.6 FSI had this model. It is 2cm wider than the classic 3l version but still very light. I did not compare rim to rim weight only complete wheels. About the tires I do have to make a comparison with the ecopias and those. I have a pair of rims with very old ecopias (scarry to drive them on wet surface). I believe that there is not a big difference (I would say 0.2-0.3 maximum on external) because I have eco version on the new tires and if I add up the contact area is the same as the ecopias only 10% weight added. The ride is far more comfortable with the 165 version...no doubt about it. Anyways...the 145 are nowhere to be found anymore. I wanted to buy a new set and no luck. Not even the winter continentals are not available anymore.

not even for the cleaning purposes? only water maybe?

Did you test water methanol injection in this engine? by any chance?

True. As I say power does not come only from air:)) you need to burn something in order to get extra horses. As lupo_3l said he used stock parts to go up to 125 and turbo was not yet at limit. It is good to hear from someone who tested stock parts to limits:). As for tire size...i am not sure that 145 makes a bit difference compared to 165 width. So far i like the ride better with the 165 and the contact surface is almost the same because of the way the tires are build. I bougth B/B markings and they seem to be much better than ecopias in terms of comfort and traction (but i still need to register the new tires and that will be a pain)

Awesome. So you are running manual gearbox? everyone says that 200nm is the limit and that is reached around 100hp if i remember correctly. It is nice to hear from someone who actually tested this things.

Thanks Manni. Yes I aim towards lower consumption but since I suspect turbo for wear I need to choose between upgrading to a more efficient turbo or repairing the old one. Maybe you are familiar with: https://forums.tdiclub.com/index.php?threads/1-2-tdi-tuning-info.390974/ I looked at what he did with his 1.2 lupo. He till has insane fuel consumption but he also done 100 other things to the car. I will not be able to go that drastic but i can implement part of modifications.

Are you sure? As far as I know Tuneko Ltd the one that tuned the 1.2 lupo a lot got 90hp from this engine with stock stuff therefore i believe the turbo is somewhat limited. The turbo on 1.4 tdi 90 is not the same with the one on 1.2 tdi. That's why I believe the 1.2 turbo is not as potent. I agree a bigger turbo has bigger lag but since only the pallets/wheels (going billet) are different I expect an improvement in efficiency for the same garret housing. I expect it to make better use of same flow since the billet wheels are lighter and have better airflow. In fact I expect lower lag because of better use of flow and decrease in spinning mass. Do you think I am looking at this wrong?

Fixed all the leaks from intake and added some superglue to the vacuum pump (there was no smoke coming out of it anymore). The turbo o-ring for the intake was a little hard to find but got one in the end. It is a different car now. It does not rattle so much in eco mode. It is a pain to drive 50km/hr (it rattles a bit because it shifts in 5th gear in eco mode). The consumption seems to have gone 1L down compared to the previous test I done in this topic last year. In eco mode mixed - mostly external I get now 3.9L/100km. In normal mode when i arrived at home after the steep hill the consumption was 4.4L/100km. I will be back with some city consumption after at least a month. (i do not drive the car that much ). STILL one weird thing: When pressuring the vacuum hoses with the smoke machine I noticed smoke coming from the engine air intake. I suspect that the tandem pump/vacuum pump is not good inside - it does not seal well between oil and vacuum maybe. The vacuum side should not communicate with the engine side/oil side at least not by my logic and knowledge so this might be another big issue. I ordered a new pump from pierburg (it seems to have a better design than the luk version i have on the car) . The new tandem pump price is around 200 euros today in 2024-05 on autodoc24 (the mobile app). This might also explain oil consumption - i taught that the valve seals might be old but now the tandem pump is also on the list. It would be nice if the pump solves the oil consumption too. The smoke test will be done again with the new pump. If the result is different this might be a good way to determine if the tandem pump is broken inside. I expect a big difference with the new tandem pump if not than the injectors and turbo will be next. The new turbo i've been looking at is this one: https://muchboost.com/product/1-2-tdi-hybrid-turbo-upgrade-audi-a2-volkswagen-lupo-seat-arosa-any-ayz/ . But for now i hope that the tandem pump will solve a lot.

Not sure if this topic has a conclusion or not. For me the bad consumption had several sources: 1)The T on the fuel filter (if you have the metal version -- the older ones) -It was cracked and air got into fuel system. 2)Air intake leaks -- on the oil stick pipe one o-ring was missing - after plugging this there was a big improvement. Also check the oil level sensor for missing or worn out orings. 3)air leak near turbo intake hose -- the o-ring was warn out and turbo was aspirating false air. 4)tandem pump might be defective inside - this is yet to be proven after I replace the current one with a new one. Find updates on my post. Usually the older version of tandem pumps had that issue with the hose plug getting loose BUT also with the seals between oil side and fuel side and vacuum side. You need to get a smoke machine for detecting leaks. You would not believe where the leaks are until you test for it. The car runs well with this leaks also and you cannot find anything specific on vag-com or computer diagnose.