As far as your exhaust manifold doesn’t have any leak. Absence of catalyst or oxygen sensor will not consume fuel.

accord v6 has 4 oxygen sensor and 3 catalyst.

But my accord only has 1 catalyst at the bottom. The two upper catalyst is missing.

Now 1 downstream oxygen sensor was bad.

I still manage to pull 17-18mpg city driving.

When my exhaust was leaking it was consuming fuel. But all this while I thought it was the catalyst. But since I went to fix the exhaust leak i was getting 18mpg with real liters of fuel not the fake from filling station.

I waited for the yellow light to come on. Drive to filling station and bought the original 3 gallon 12 liters. You can buy into container to be sure it’s actually original liters you pour inside.

When I drive and the yellow light come up. To my calculations its 17-18mpg. Despite absence of catalyst and 1 bad o2 sensor.

nurey come and see oh...

dicksonadams:
nurey come and see oh...

Without evidence, you go explain taya

18miles per gallon.
28.8 kilometers per 4 liters(US gallon)
That's 7.2km/L for a 3.0L engine..
Hmm.

You must be kidding. Those 2 elements are the major supplier of fuel to engine. Catalyst and 02 sensor. Your engine will be dumping additional fuel by 15% leading to poor gas mileage. If I'm lying take a towel and go to your muffler. Wet towel,early in the morning,use it to wipe the muffler. The result will be black sooth amon the exhaust. Dark black. 02 sensor and catalyst are doing team work .

AutoManual:
As far as your exhaust manifold doesn’t have any leak. Absence of catalyst or oxygen sensor will not consume fuel.

accord v6 has 4 oxygen sensor and 3 catalyst.

But my accord only has 1 catalyst at the bottom. The two upper catalyst is missing.

Now 1 downstream oxygen sensor was bad.

I still manage to pull 17-18mpg city driving.

When my exhaust was leaking it was consuming fuel. But all this while I thought it was the catalyst. But since I went to fix the exhaust leak i was getting 18mpg with real liters of fuel not the fake from filling station.

I waited for the yellow light to come on. Drive to filling station and bought the original 3 gallon 12 liters. You can buy into container to be sure it’s actually original liters you pour inside.

When I drive and the yellow light come up. To my calculations its 17-18mpg. Despite absence of catalyst and 1 bad o2 sensor.

You are right. But it's not just any oxygen sensor. If your upstream oxygen sensor was bad, you will keep buying fuel like mad. But the downstream oxygen sensor and catalysts have little effect on the fuel consumption.

I have same accord, v6. I regularly do 290miles (460km) on a 60litre tank, city driving with no traffic.

emy77:


You are right. But it's not just any oxygen sensor. If your upstream oxygen sensor was bad, you will keep buying fuel like mad. But the downstream oxygen sensor and catalysts have little effect on the fuel consumption.

I have same accord, v6. I regularly do 290miles (460km) on a 60litre tank, city driving with no traffic.

I guess the downstream sensor after the catalyst is not important like that, that one is the efficiency of the catalyst reading. The main one is the upstream before the catalyst.

Used oxygen sensor they said 10k that why I didn't buy. and I wasn't really sure of the impact.

Form my observations, When my yellow 🟡 light come on I drive 3 miles to filling station then Added 3 gallons.

The yellow 🟡 light disappeared. I quickly reset my trip meter.

Then the yellow 🟡 came on at 50 exactly 50miles.

I still continue to drive the car for 10miles and parked it.

There was alot of ON and OFF on idles this one will consume some amount of fuel too.

This evening I bought 5litter in gallon and pour inside.

I start the car. To my shock the yellow 🟡 light is still on. Because I only added 10miles after it comes on.

It maybe that if the yellow 🟡 come on. For instance when you have 10L and you waste 3l from it. If you add 5l making 12L the yellow light will still show. Maybe if you have something much more in there before it will go.

I will need to experiment with this to be sure. Because this night own wan confused me why the yellow 🟡 light on after adding a gallon.

emy77:


You are right. But it's not just any oxygen sensor. If your upstream oxygen sensor was bad, you will keep buying fuel like mad. But the downstream oxygen sensor and catalysts have little effect on the fuel consumption.

I have same accord, v6. I regularly do 290miles (460km) on a 60litre tank, city driving with no traffic.

is your downstream oxygen sensor bad?

HenryWilliams:
18miles per gallon.
28.8 kilometers per 4 liters(US gallon)
That's 7.2km/L for a 3.0L engine..
Hmm.

consume low or too much?

AutoManual:
is your downstream oxygen sensor bad?

I have a p0141, bank 1 sensor 2. Even though I plan to change it and see if the economy improves further.

emy77:


I have a p0141, bank 1 sensor 2. Even though I plan to change it and see if the economy improves further.

I doubt if there will be improvement. If at all it will not be noticed.

Same with mine. Bank 1 sensor 2.

AutoManual:
I doubt if there will be improvement. If at all it will not be noticed.

Same with mine. Bank 1 sensor 2.

The fuel level sender is affected by gravity so not the basis for calculating fuel economy. As your vehicle get inclined the fuel sender won't show true value. If you have been driving for years you will notice anomalies of reserve light coming on then going off, fuel guage increasing then decrease depending on angle of inclination.

For a true picture buy full tank, drive a certain distance then go to filling station and buy full tank then note down how much fuel the tank took against distance travelled, 3 instances of this will give you an idea of your mpg.

Catalyst is not about fuel economy but converting harmful gases to mild gases before been pushed out from the exhaust, to even increase good mpg people remove catalyst and weld straight pipe to increase back push.

But you see those A/F sensor and O2 sensor bolted on the exhaust path, if they are faulty, your vehicle go dey drink fuel like hippopotamus. The dreaded P1157, P0141, P0300 to P0304 random cylinder misfire etc.

You may still be getting good mpg in city if you have a light foot but highway anything from 3rpm upwards your fuel go dey fly fly.

nurey:


The fuel level sender is affected by gravity so not the basis for calculating fuel economy. As your vehicle get inclined the fuel sender won't show true value. If you have been driving for years you will notice anomalies of reserve light coming on then going off, fuel guage increasing then decrease depending on angle of inclination.

For a true picture buy full tank, drive a certain distance then go to filling station and buy full tank then note down how much fuel the tank took against distance travelled, 3 instances of this will give you an idea of your mpg.

Catalyst is not about fuel economy but converting harmful gases to mild gases before been pushed out from the exhaust, to even increase good mpg people remove catalyst and weld straight pipe to increase back push.

But you see those A/F sensor and O2 sensor bolted on the exhaust path, if they are faulty, your vehicle go dey drink fuel like hippopotamus. The dreaded P1157, P0141, P0300 to P0304 random cylinder misfire etc.

You may still be getting good mpg in city if you have a light foot but highway anything from 3rpm upwards your fuel go dey fly fly.

Umm. Full a tank for this tinubu government?
The yellow light might not be accurate but it very close to an idea states. Even if it below that let say 15miles its fair enough for Old car with missing components and bad fuel.

ok but what is the work of the downstream oxygen sensor? After the catalyst?



See attached picture. It has nothing to do with fuel.

Update.

I there was a total of 60 miles. When i drove it yesterday to filling station. I added 1.5 miles that 61.5 miles. I bought fuel N4000 @610 it was 6.5 fake litters. From my previous observations of that filling station 6L is 5L.

So i will just assume it was 5.5 litters. I was surprised the way the gauge went up it crossing quarter of the gauge.

The car is now 76 miles. That means i added 16 miles. I will just wait again until the yellow light come on and check the miles by than i will know the actual rate.

Total fuel added 22 real litters. Currently 76 miles. Waiting till the yellow light will come on.

2003-2007 Honda Accords have a total fuel tank capacity of 17 gallons (65 Liters) and of that total amount of fuel it keeps a reserve tank capacity of 4 gallons (15 Liters)

I got 90 miles from 23L

AutoManual:
As far as your exhaust manifold doesn’t have any leak. Absence of catalyst or oxygen sensor will not consume fuel.

accord v6 has 4 oxygen sensor and 3 catalyst.

But my accord only has 1 catalyst at the bottom. The two upper catalyst is missing.

Now 1 downstream oxygen sensor was bad.

I still manage to pull 17-18mpg city driving.

When my exhaust was leaking it was consuming fuel. But all this while I thought it was the catalyst. But since I went to fix the exhaust leak i was getting 18mpg with real liters of fuel not the fake from filling station.

I waited for the yellow light to come on. Drive to filling station and bought the original 3 gallon 12 liters. You can buy into container to be sure it’s actually original liters you pour inside.

When I drive and the yellow light come up. To my calculations its 17-18mpg. Despite absence of catalyst and 1 bad o2 sensor.

Is 18mpg really good for a sedan?

My Civic 08 gets just about 400km on full tank.
Mechanic changed the fuel pump filter, but it has done nothing. He scanned too, brought nothing.

Elxandre:
My Civic 08 gets just about 400km on full tank.
Mechanic changed the fuel pump filter, but it has done nothing. He scanned too, brought nothing.

check your fuel trim numbers

dicksonadams:
check your fuel trim numbers

What does that mean bro?

Elxandre:
My Civic 08 gets just about 400km on full tank.
Mechanic changed the fuel pump filter, but it has done nothing. He scanned too, brought nothing.

2008/12 Honda Civic fuel consumption in city - 9.7 l/100km, highway fuel economy - 5.5 l/100km. Fuel tank capacity is 50 litres or 13.21 gallons, when you car shows yellow light you still have about 10L.

50L is 500km at most. In your case consider poor fuel, aging and reservoir in your tank, you can’t empty the full tank. So let say 40l might be usable. 400km is not bad afterall.

Elxandre:

Is 18mpg really good for a sedan?

yes for v6 3.0L

Elxandre:

What does that mean bro?

some cars have mpg meter displaying the numbers. I doubt if its on your civic