System Too Lean - P0171 (FUEL CONSUMPTION ISSUES)

[ahmedstudio]

This tooll has graphical data as well. Should I share a recording of graphical data while driving or idle?

[Xulfiqar]

graph the primary o2 at idle

[ahmedstudio]

The took is asking about assigning PIDs to x axis and y axis. See the attached image. What should I do

[Xulfiqar]

o2 and time

[ahmedstudio]

"Time since engine running" ?

[Xulfiqar]

should have a simple time PID too, its just in seconds.

[ahmedstudio]

Here it is, 42 seconds data for Primary O2 sensor on idle.

[Xulfiqar]

it is switching proper, your tool is trash though.

Its ficksed, keep on driving.

[ahmedstudio]

Ok. Now should I change engine oil? It's only 540 km driven and looks diesel like black because of overfuelling recently. Is viscocity still intact or it's just the colour of oil darkened?

(The tool has Bluetooth lag)

[Xulfiqar]

keep on driving. and change it at half of normal interval. Unless you have an itch to burn your money.. Better spent on charity..

The black sludge will take a bit of time to flush out.

[ahmedstudio]

Yes that's why I asked. I'm not keen on spending in what's not needed. Sir g، you and Raja Atta bhai @rajaatta always make fun of me . I am just passionate about mechines and a humble learner, and learnt a lot from you guys. Knowledge is irreplaceable and I am grateful to you and fellow experts.

Is engine flushing with flushing products recommended? Or it would flush with oil change?

[Xulfiqar]

make fun??

sorry if you felt offended - I was just brought up like that. Always asked to what I was doing in the same way - Its oldschool Karachi upbringing.

no need for flushing agents, just oil change will clean it out eventually. (make sure engine runs at normal hot temperature - cold temperature kills the oil as moisture doesnt steam out)

[rajaatta]

So that was fun !!!!! Hmmmmm
I think saving your time and effort by pointing out the axact faults is not fun.
I am a diagnosers and my job is to pinpoint the issues from data lists observation and experience and was saving your time if you understand.
But it's your choice either you choose a motorway path or like to travel through barn fields to your destination. That's it.

@xulfiqar he don't make fun of any body

I think you should dig more because you had not yet met our legend cheena malaii Friend who would staightly shoots you with his funny methi methi bistiiii

@vcheng

[ahmedstudio]

Sir my bad I couldn't communicate my humour
You said nothing offensive. Its just that I was relieved with this fuel consumption problem solving with your help, so I said it in a light way and would love your humour in future.

[ahmedstudio]

Sir I said it in a light manner in a friendly way . Of course I am grateful to your expert opinion and help and indebted to you.
I was relieved with solution of problem so I said it in a light manner. And I do love it when you guys say stuff like that like an elder and knowledgeable person.

[rajaatta]

Don't drag our comments to your heart once I was like you brother but now we all are grown up and please do understand this was your only car you were working on we had to work on lot of cars daily so you can imagine what would be our situation when we told some one a short way to fix and he asks us to sing the whole alibaba song for explanation.

Don't take it personally man. No one would make fun of you.

[rajaatta]

Don't put any of the flushing agent in the engine oil let the oil stabilize by itself. You had just recovered from extreme rich mixture. Mixture at this stage can easily wipe out the rings so it's better not to flush it and drive calmly for next 5000kms and change the oil as advised by @Xulfiqar the engine oil would dissolve the contamination of the rich mixture.

[ahmedstudio]

You are absolutely right

[ahmedstudio]

Ok. Suggestions noted and will do so only. Thank you so much

[ahmedstudio]

@Xulfiqar @rajaatta After driving for around 300 km, the long term fuel trim has stabilised at -14% on idle (it was at -3% after driving 50km).
LTFT beyond -10% means that ECU is trying to compensate for rich mixture.

I checked the engine coolant temperature, it's around 70-80 Centigrade on idle. (It's less than ideal operating temperature of 87 C, am I right?), So perhaps engine is not reading ideal operating temperature, so fuel mixture is rich? There is no DTC code.

LTFT stays on higher negative value of -14% only ok idle, while driving it staus fluctuating between -10% to 10% (which is I guess perfect???). So perhaps something wrong with engine while it's on idle. On cold start, the engine takes more fuel and time to reach optimal temperature, than usual.

Attached is OBDII Live data image and a 4 minute drive and idle video.

Please advice

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