Tiisseli

No, but might be e85 fuel, it has some different additives than normal 95e10. Now I use only e10 because prices change and e85 came more expensive than e10.

It was a little reddish, nothing else obvious.

Everything seems to be normal now! I replaced the pre-cat lambda probe, cause its values were so much off. These cars seems to use o2 sensors straight from start and adjust the mixture, even my obd showed "open loop" condition after cold start. Thanks everyone for helping!

Thank you! Went to get some groceries and problem was there again. Pre-cat sensor was reading from 2.300mA up to 3.900mA and lambda was again 1.299. Post-cat sensor vas reading up to 0.999V. After driving long time I was able to get these number back to normal again. If internet has taught me right I would say its running more rich than lean? At least by smell of gas after idling... I wonder how I can measure pre-cat sensor voltage? On OBD I am only able to get milliamps. Training is still in progress...

Ok, took the car to another test drive and this time everyting was great, all symptoms were gone. At cold start pre-cat sensor showed first around -0.800mA and it settled to around zero in couple of minutes. Lambda value first was around 0.880 and settled around 1.000. Post car sensor is switching between 0.750-0.900v. On OBD tool open loop condition changed to closed loop, when engine temperature got 60°C. Fuel trims kept at zero whole OL time. When OL changed CL fuel trims went around -2.3%. I didn't save the freeze frame when problem was there (stupid me) and o2 sensor data is missing. I do remenber though the lambda value were whole time 1.299 which is maximum lambda value, when short fuel trim was 39.8%. In my opinion engine is not even able to run with values like that, so I started thinking if the pre-cat probe is not sometimes functioning as should or ECU is living its own life.

On Freeze frame/live data there is "FUELSYS1" and after that "Open Loop" or "Closed Loop"

Looked from generic OBD tool, not sure if its accurate. But it seems to be only thing which distinguish right and wrong engine behavior.

Both lambda probes has been replaced a year ago with bosch sensors. On closed loop it works perfectly but on open loop it doesn't At around 86°C it starts working as should, but this happens only if it changes to closed loop, sometimes stays on OL for longer time. On open loop it keeps system too lean. If I have understood right, on closed loop ecu uses sensors to create right air fuel ratio, but on open loop it use only program?

Yes and I will test taking it out next time I fill up. I took a test drive after work and again with cold engine there was lean mixture, but when it got to working temperature OL-condition changed to CL-condition and everything was back normal.

Hi. My fabia 2003 1.2 12v (AZQ) have been getting code p0171 for a while. I've looked fuel trims and when check engine light is on, short fuel trim shows 0% and long fuel trim -4.7%. When codes cleared, short fuel trim is 39.8% and long fuel trim the same -4.7%. This happens only when engine is half warm. When engine is warmed fully up, fuel trims are normal. Code appears on open loop condition, but it seems that ecu doesn't change to closed loop even with warm engine. Fuel consumption is sometimes 15L/100km and sometimes 7L/100km on steady speed. Also sometimes theres a huge power loss which comes with increased fuel consumption. Whole intake has been inspected for leaks but none is found. The car has been modified for E85 with eflexfuel ethanol kit, but i think it's not the problem because it does the same with pure gasoline. Any suggestions for next steps?