tici

🤔 too difficult or too obvious...

Hey! I worked near Hannover for a couple of years... (Minden + Stadthagen) are you close?

Hi guys, I'm experiencing a situation that I can't explain. The car is a 2017 Yeti with a CZDA engine (gasoline 1.4 TSI EA211) 110 kW / 150 PS and 90'000 km. No DTC, all tests are fine (misfire, cat, lambda probe and so on). No air leaks (map at idle 30 kpa or even less). The car runs normal, starts normal, nothing strange... Mileage: around 7.4 L/100 km pretty constant. But... the LTFT are +10% at low load and rise up to +15% at high load. The spark plugs are all the same: white, clean ceramic and a little black on the metal, just a little. IAT and MAP are fine (cold car: same temperature on all sensors, MAP and BARO same as the external pressure), The rail pressure is strange: the low pressure pump produces about 740 kpa (7.4 bar) - engine off. This is normal. When I start the engine the pressure rises up to 14000 kpa (140 bar) at idle. Normally it should be 50-70 bar. At high load it rises up to 22600 kpa (226 bar). This mean (to me) that the rail pressure sensor is fine and the CPU is commanding this high pressure to inject more fuel. Probably there is a limitation in increasing the injectors opening time, so the correction is part with the injectors, part with more pressure. The LTFT are non jumping up and down and the STFT are +/- 10% and average to 0% (this is normal). So the corrections are pretty consistent: "a quite adaptation to some kind of situation". All those data are the result of long scan and evaluation of the values with excel (pivot and so on), so it's not just one quick reading but values collected during 1+ hours. Years ago I was messing around (tuning) with american cars (V8 GM) and it was pretty easy to spot problems, but it wasn't direct injection, so now I'm pretty puzzled. At that time a "good tone" was with LTFT at +/- 2%... +15% is totally out of tune... or? Another thing: the guy that sold me this car replaced the valves as some of them did touch the pistons (...). how wrong can you do this job to have +15%? If it was one cylinder with bad compression it should be 60% too lean, to result in +15% in average... at this time it would be already melted and the spark plugs would show the difference... plus some misfire... Many thanks in advance for all your inputs! 🙂

Hi I just bought a 2017 Jungle Green 1.4 TSI 4X4 Yeti. I know US cars pretty well, but not Skoda (nor VW or Audi...). Glad to learn from you guys and to share my knowledge!