TitusM

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.

I did not find the time to rebuild the engine. I am just very glad for finding the leaks posted above. I will come back with fuel consumption after this fixes. Next will be: 1)Injectors check and maybe repair if necessary. 2)Turbo check and clean - maybe upgrade the core and then a remap. 3)compression check although now after fixing those leaks i believe there will be a major improvement. 4)high pressure pump replacement with something newer that does not suffer from the vacuum hose issue. I am not sure I will do those this year. I still want to take out the engine and do a full check and rebuild but that requires also a garage that know I do not have. In the mean time since I did not write I had issues with the clutch hoses. The special clamp for the pressure hoses that go to the hydraulic actuator got broken and left me stranded for a while. I did purchase 3 clamps :)) for 20 euros/peace:)) I bought a wet aspirator and cleaned the seats. Another very good 100euros investment that will potentially save lots of money in the long run with the interior cleaning. The little bug did get a new set of wheels and summer tires. Unfortunately I could not find the original 145 ecopias anymore. Apparently 2023 was the last year you could buy those. I installed 165 version. The total weight is 1kg extra for each wheel compared to the winter continentals (10kg vs 11kg with new wider rims also) . I think the Lupo 1.4 fsi rims look much better than the 1.2 tsi vesion:). I got the rims from Poland.

1000 years later::)) update: I just bought from aliexpress a smoke machine for leak detection. I think this is a must have for this older cars. Issues i discovered: 1) huge leak near the oil sensor because of a missing o-ring. Solve it and the car already drives better. 2) small leak near the turbo intake. I have to remove the pipe before the turbo to see what is going on there but it leaks quite a lot 3) the classical leak from the vacuum pump hose (this one was very little but still there). I will try to find a good price for a new high pressure pump. My current consumption before fixing number issue 1) is city ~6.5l/100km and 4.3 external.

Reviving this topic after a long time:) I just purchased a full bose system from ebay -- wiring, amp, speakers etc. Thanks for all the hard work you've done long ago. It was very helpful to check all the wiring. I successfully installed it today but I have a few "errors": 1)It does not say bose at the beginning even after coding with vagcom - this is not so important but maybe useful for debugging. 2)The radio does not have front/rear anymore -- only left and right in settings. Is this normal (the blaupunkt version had fader -- front/back setting)? I own a2 1.2tdi 2001. I tried with the bose cable to eath connected and disconnected -- with coding and without coding and the result is the same. The unit sound good. There is tons of bass but i still have the old blaupunkt speakers and the subwoofer. This is another question -- is it worth the trouble in changing the speakers to bose ones?

Back after some more time:((( The consumption is still higher that other cars. The valve only solved part of the problem. I just bought a compression tester and injectors o-rings. After opening up the injectors I will decide if I will sent the injectors for rebuild.

@vfralex1977 Although 057127247A fits maybe the B version would be more suitable since the engines it is designed for have smaller power (90hp+). BUT the B version seems to have a different top. Maybe diameters are the same. let us know how "A" works for you.

8Z0501541 nicht mehr lieferbar. Was ist die beste Alternative? funktioniert 6Q0501541E?

The right side wish bone is not available at all in 2022..:((((. You can still find some on the left side. So from now on only refurbishing is available retro-mobile

@vfralex1977 Found the difference: So for the 1.2 the return line opens only when reaching 60 degrees:)))))) If no aftermarket part is found then the one with A should be fine. The only difference is that the engine will warm up later.... "On the 1.2l TDI engine, the fuel pre-heating valve does not open up the path to the fuel tank until the fuel temperature exceeds 60°C (1.4l TDI engine >30°C). As a result, the heat is concentrated on the engine and the engine reaches operating temperature more quickly"

Can you compare the 2 parts when they arrive? (FIRST let them site a while in the same temperature - they have a thermal plate inside) I tested mine blowing air with my mouth trough it and so I detected different air flow.

Well I fitted the one from vaico on a mann filter with no problems BUT make sure you install the valve out of the car. It is very hard to press it in the filter housing if you are under the car. This is the part I installed (and lots of other producers are available): https://www.autodoc.co.uk/vaico/2214688 I am pretty sure that the suggested part with 1J does not fit. (maybe some adaptation is needed but I do not see the reason if the one with A works well) I am not sure if changing to the plastic housing is a good idea. If something goes wrong with that housing you need to change it completely so you are back to the same job as for metal filter BUT it makes filter change 100 times easier AND I am pretty sure that using a "A" valve is the same as using a universal plastic housing. I usually change the fuel filter alt least every 2 years. (2 oil changes)

I took a closer look and indeed there are multiple letters.... And each letter is in a circle...it seems I was wrong. None of them seem to be listed as compatible with a2 1.2. Soooo this means there might be a difference in pressure and opening temperature. In my case this thing was cracked and air got inside the fuel system so ... maybe someone else can give some extra details?... Why the same part can fit multiple cars. This one seems to have a very different mounting

Do you have some links for the other versions? I paid 10euro for the part aftermarket. Oem is around 50.

The E is not part of the code for the part. And I could not find any valve without a letter. There is only A and B at the end and the mounting is different for the B. The A at the end seems to be the one to go - it was also listed as compatible. The only big difference is the color - the original was white and the new one is black. Maybe the opening temperature is different but this should not be a big difference in the way the car runs. Anyhow this improved only consumption when under load (and fixed the priming issue in my case). After driving a bit is around ~0.5 lower consumption.

Found the issue: the valve on the fuel filter: 057127247A A picture from the internet: - this is the valve in question

Found the issue: the valve on the fuel filter: 057127247A I replaced this AAAND : 1) the idle is not so rough 2)after long idle there is no white smoke on the tail pipe 3)fuel consumption is better - have to make longer runs to confirm (it looks like ~1.5 liters lower for city or hard drives --instead of 6.5L/100km now i've got ~5L/100km) 4)injector correction is much better. Before I've seen 0.5 correction when the engine was warm. Now injection correction is as in picture. From now on I will replace this together with the filter(every 2 years).

Some updates after a long time. The consumption is now around 6.4 l/100km. I was wandering if the knock sensor might have any influence in bad fuel consumption? I understand that for petrol engine at least this is an important part and it does not always raise error. I am programing also some injector repair this summer. Hopefully it will not be that expensive. I noticed that after the car idles for 30 minutes there is some white smoke on the tail pipe if I accelerate. I believe is some unburned fuel(it smells very bad), hopefully is not the head gasket. The car does not seem to suffer from performance issues or any liquid loss. google translate: Einige Updates nach langer Zeit. Der Verbrauch liegt jetzt bei 6,4 l/100km. Ich bin gewandert, ob der Klopfsensor einen Einfluss auf den schlechten Kraftstoffverbrauch haben könnte? Ich verstehe, dass dies zumindest für Benzinmotoren ein wichtiger Teil ist und nicht immer Fehler verursacht. Ich programmiere diesen Sommer auch einige Injektorreparaturen. Hoffentlich wird es nicht so teuer. Mir ist aufgefallen, dass nach 30 Minuten im Leerlauf etwas weißer Rauch am Auspuffrohr entsteht, wenn ich beschleunige. Ich glaube, es ist unverbrannter Kraftstoff (es riecht sehr schlecht), hoffentlich ist es nicht die Zylinderkopfdichtung. Das Auto scheint keine Leistungsprobleme oder Flüssigkeitsverluste zu haben.

Maybe this info from our German friends will help (use chrome and auto translate): https://wiki.a2-freun.de/wiki/index.php/Gelenkwellen

Thanks, There has to be a small filter of some sorts to block large things from entering the pipe system ...but if there is no pump it might just the pipes.

I did the operation above - with "Diesel Purge". The cylinder deviation seems to be the same. After warmup cylinder 3 goes on the plus side. The filter was not black as in video. The return line was pretty clean. What I found out and it's weird is that the trunk pump does not seem to work (but the car starts and works) - isn't there a low pressure fuel pump?. On the diesel line from trunk (in picture below - the closed loop) there is no movement...I expected to have diesel running from trunk and to go in return line...but it does not. The car starts with no problem... but as far as I know there is a small low pressure diesel pump in the trunk that should work. Is the A2 different? @Phoenix A2 , @janihani, @DerWeißeA2 any idea about the above - trunk pump related? Could this influence the fuel consumption or is this normal - the trunk pump is just a "filter" and level sensor?

update: I readjusted the torsion value to be on the plus side. (new rear brake pads, cables and pistons) I noticed that cylinder deviation is better now at idle at least - after torsion value reset. New log: - same run - but all 3 in one ->all 56 km (city and highway ). Non eco...and a bit of race style (sorry i was afraid to go over 180 on the highway because is not straight - no wonder it's limited speed). Consumption 5.3 when home....Better than last time and with Non Eco - this is at least weird. It was a little wormer outside. I will have to redo the same run but with eco on all the way. (i think there will be very little difference in consumption - only in car feel) https://log.tunezilla.com/s/SXzPAZNj Next I will do this and injector gaskets change. Hopefully the injector deviation will be better.

I will go to a certified dealership in town to clean the injectors and replace the o-rings. Hopefully it will not be a very expensive job. A complete rebuild for an injector is around 100euros (completely new parts from bosch). Since it is only cleaning and oring replacement.... The oring kit cost around 15 euro for one injector but I have no idea how much does the work cost (I am a little bit afraid to diy - i might miss some tools). I read some more and it seems that it is possible to have higher consumption because the "holding" o-rings from the injectors are worn and fuels gets loose from return line to the cylinder. Logs to come after injector cleaning and oring replacements (1-2 weeks maybe)

Modified torsion value: Logs here: https://log.tunezilla.com/s/l71v76IY Now is a little bit under 0. (the value is correct on the graph - it is true what you said group 004 field 4 for torsion value)

true... If you speak nice with it it might work as intended and might even take you to the seaside .

I was thinking the same thing with torsion value. I will redo the logs tonight with new torsion value. I did this before the timing belt was changed this summer. It seems that the tools from the mechanic were a little used (but at least is on + side not on -) As I understood it is important to have the value around 0.5, is this right? PD engine like a little bit of+ there. What about injectors? what do you think? is is possible that cylinder 3 injector to have some issues? I am thinking of this because 1.2 is a small engine and maybe tolerance should be smaller? Or this might be corrected after torsion value adjustment? (i have to connect the vcds to the car to see the group for torsion value - i will come back with update on this question) I see torsion value above 3 in graph (if the group is correct as you mentioned):