Fuel consumption went up
Thread Starter
Instructor
Joined: Aug 2013
Posts: 1,058
Likes: 149
From: Vaudreuil, Canada
Fuel consumption went up
I have a 2017 IS200T that usually averages 7-8/L/100 km, but now it sky rocketed to 14-15L/100km.
Also, if I floor it, the gas mileage drops, which doesn't make sense to me either.
Has this happened to anyone? if so, what was the fix?
Thanks!
Currently at 129,500 KM
Maintenance:
94,000KM Spark Plugs
128,900KM Oil Change (0W20)
Tires are at 36 psi all around (Kumho Ecsta PS31 tires if it matters at ~70% thread remaining)
BMS intake with an AEM filter (replaced today with a new air filter)
Cleaned the MAF sensor
Invidia Q300 axle back (mileage was fine for the first 2 weeks with this exhaust, third week (now), it got worse from one day to another)
Resolved:
Fram air filter was throwing off the readings.
Invidia Q300 was not the issue
Spark plugs were not the issue
BMS intake was not the issue
Cleaning a MAF sensor did not solve anything
The calculation was right, but the counter was off, which is why I didn't do these steps:
Clean the throttle valve
Put fuel cleaner
Also, if I floor it, the gas mileage drops, which doesn't make sense to me either.
Has this happened to anyone? if so, what was the fix?
Thanks!
Currently at 129,500 KM
Maintenance:
94,000KM Spark Plugs
128,900KM Oil Change (0W20)
Tires are at 36 psi all around (Kumho Ecsta PS31 tires if it matters at ~70% thread remaining)
BMS intake with an AEM filter (replaced today with a new air filter)
Cleaned the MAF sensor
Invidia Q300 axle back (mileage was fine for the first 2 weeks with this exhaust, third week (now), it got worse from one day to another)
Resolved:
Fram air filter was throwing off the readings.
Invidia Q300 was not the issue
Spark plugs were not the issue
BMS intake was not the issue
Cleaning a MAF sensor did not solve anything
The calculation was right, but the counter was off, which is why I didn't do these steps:
Clean the throttle valve
Put fuel cleaner
Last edited by Lex_Giorgio; Sep 18, 2023 at 01:15 PM.
Intermediate
Joined: Jun 2014
Posts: 285
Likes: 47
From: Hong Kong
Thread Starter
Instructor
Joined: Aug 2013
Posts: 1,058
Likes: 149
From: Vaudreuil, Canada
I did one manual test:
10.833 liters and it gave 130 km, which works out to 8.3L/100km yet the car was showing 12L/100km (counter was reset)
The reading is off, but the consumption right
Intermediate
Joined: Mar 2018
Posts: 422
Likes: 64
From: H
Not too sure if this will make much difference for you but I have fuel cleaner put in every 5,000 miles for my service interval at my dealership. However I use it every 2-3 months to keep the fuel system in better shape since I plan to own the car a lot longer than my previous cars. When you had your tires replaced, did you get an alignment as well (Not that it matters but sometimes it does help, with my roads my alignment was off within 2 years of ownership).
The exhaust will burn a bit more fuel since you are trying to enjoy the car. My mileage went down drastically when I put in the intake then the exhaust after a few months. After you are done playing around, the mileage gets better. It might actually be the way you drive the car as well and which mode you are in. I notice that city and highway when I'm driving like a civilized person my mileage is great in ECO mode. When I decide to just gun it at any corner my mileage drops. I also heard that it's better to drive in NORMAL mode on the highway as well.
The exhaust will burn a bit more fuel since you are trying to enjoy the car. My mileage went down drastically when I put in the intake then the exhaust after a few months. After you are done playing around, the mileage gets better. It might actually be the way you drive the car as well and which mode you are in. I notice that city and highway when I'm driving like a civilized person my mileage is great in ECO mode. When I decide to just gun it at any corner my mileage drops. I also heard that it's better to drive in NORMAL mode on the highway as well.
Thread Starter
Instructor
Joined: Aug 2013
Posts: 1,058
Likes: 149
From: Vaudreuil, Canada
I've never tried the fuel cleaner, but I'll give it a shot.
Never got an alignment on this car (even with the new tires), all the tires wear evenly though.
Driving habits haven't changed, even with the exhaust, but the gas consumption got worse 3 weeks after having the exhaust, it wasn't right away. I'm always in normal mode, never Eco.
It's the counter that's off, usually when the car is idling, the liters per 100km go up but now it's going down. I'm going to check the spark plugs tomorrow, it's the one thing that I didn't check again.
Never got an alignment on this car (even with the new tires), all the tires wear evenly though.
Driving habits haven't changed, even with the exhaust, but the gas consumption got worse 3 weeks after having the exhaust, it wasn't right away. I'm always in normal mode, never Eco.
It's the counter that's off, usually when the car is idling, the liters per 100km go up but now it's going down. I'm going to check the spark plugs tomorrow, it's the one thing that I didn't check again.
Last edited by Lex_Giorgio; Jun 2, 2022 at 10:08 PM.
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Intermediate
Joined: Jun 2014
Posts: 285
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From: Hong Kong
I also have q300 installed on my IS, it certainly increases fuel consumption as it's losing the low RPM torque but it shouldn't be as much as you described. You may want to take a look at the O2 sensors readings on both pipes to see if they were normal or not...
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Thread Starter
Instructor
Joined: Aug 2013
Posts: 1,058
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From: Vaudreuil, Canada
Like I mentioned before, the reading in the car is off, but if I calculate it manually, the fuel consumption is right.
Intermediate
Joined: Jun 2014
Posts: 285
Likes: 47
From: Hong Kong
Thread Starter
Instructor
Joined: Aug 2013
Posts: 1,058
Likes: 149
From: Vaudreuil, Canada
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From: GA
I've never tried the fuel cleaner, but I'll give it a shot.
Never got an alignment on this car (even with the new tires), all the tires wear evenly though.
Driving habits haven't changed, even with the exhaust, but the gas consumption got worse 3 weeks after having the exhaust, it wasn't right away. I'm always in normal mode, never Eco.
It's the counter that's off, usually when the car is idling, the liters per 100km go up but now it's going down. I'm going to check the spark plugs tomorrow, it's the one thing that I didn't check again.
Never got an alignment on this car (even with the new tires), all the tires wear evenly though.
Driving habits haven't changed, even with the exhaust, but the gas consumption got worse 3 weeks after having the exhaust, it wasn't right away. I'm always in normal mode, never Eco.
It's the counter that's off, usually when the car is idling, the liters per 100km go up but now it's going down. I'm going to check the spark plugs tomorrow, it's the one thing that I didn't check again.
Summer gas blend vs winter.
Thread Starter
Instructor
Joined: Aug 2013
Posts: 1,058
Likes: 149
From: Vaudreuil, Canada
@arentz07 did you notice a difference after using Techron?
I saw on YouTube that it doesn't do much for the valves, but maybe it works for fuel injectors, which is why I'm asking.
Reference video:
I saw on YouTube that it doesn't do much for the valves, but maybe it works for fuel injectors, which is why I'm asking.
Reference video: