O2 sensor

[pino]

Hi! I'm Alex, proud owner of a 14 year old SE EXEC Accord (a real upgrade from my old EG) with H&R suspension, MAK Vollare wheels and a lazy O2 sensor.
I kept searching on different forums but I couldn't find an answer for my question: How much are the mpg and engines "health" affected by a broken upstream O2 sensor?

My accord can't pass 20/28 mpg (urban/extra urban) even if I drive like my grandpa.

 

[AndyB1976]

Hi Alex, welcome to TypeAccord.

It can affect the fuel strategy, I believe its more likely to run rich if the o2 sensor is out so you might experience lower than expected economy, not that the 6th gen is that great in my opinion.

Here is a datalog from my f18b2 engine, you can see when Closed Loop is in operation it tends to pull the Short Term Fuel Trim back as it appears to be detecting a rich mix. If the o2 was faulty or not working then there is no further corrections that can be made i.e. it can't lean out the mix or reduce fuel delivery.

A good video to watch is this one on Fuel Trims, from a more qualified point of view than mine!!

https://www.youtube.com/watch?v=oRX2V6_a3dc

 

[pino]

Thank you Andy for your response. Great course!
It gave me an idea of what to do in this situation.

Firstly I'll check for any vacuum leaks, test it for a few miles and buy an used but functional O2 sensor just for testing purposes.

 

[Havoc]

Hi, a faulty sensor has its symptoms -> low fuel economy, loss of power and u will smell petrol almost all the time. I remember when mine was faulty, I ran on 11 MPG but not loss of power... then i went on diagnosis and little guy was faulty. I recommend u to replace it only from Honda dealer specially for your engine.

 

[pino]

Fortunately... I used an OBD2 scanner and found out that the upstream o2 sensor is good.
I have no idea where my head was when I read that the P0141 code is for the first o2 heater circuit.

After I (hopefully) pass all my exams, I'll start working on the car. I'll start by changing the sensor and clean the EGR and throttle body.

Maybe i'm asking too much form the car. Maybe it can't get 40 mpg. It is 14 years old and has over 120000 miles though...

 

[Havoc]

no buddy, u cant get 40 from 2 litre engine.... u can get 9-10l/100km in urban (i see u are from Bucharest) with manual. I got AT and i have 12l/100km urban and 10 extra urban

 

[pino]

9-10 l/100km is actually my goal in granny urban driving style, but now I'm looking at around 16 in daytime traffic and 10-11 during the night.
I went to the sea side the other week and on the highway, at 100km/h in 5th gear, I was looking at an average of 11l/100km and 14l/100km at 130km/h with AC and cruise control.

Anyway... Until I fix the issues I mentioned earlier, all my arguments and complaints regarding the car's low mpg are pointless.

 

[Havoc]

kinda high comsuption IMO