silver_shark

hey guys, wasn't sure where to post this, mods please move as necessary. i've noticed over the last couple of weeks that my L/100km rating is increasing. i only use 91 octane or higher. i've had it as low as 7L/100km (only for a short time after filling up) but normally run in the 11-12L/100km range. after my last three fill ups, it has not changed from 12L/100km until my most recent fill up which brought it down to 10L/100km using 94 octane. now i have gone up to 13L/100km and it seems to be staying there. any suggestions? I have absolutely no engine mods (intake etc.). only thing i've done to the car is the stage 4 exhaust (will likely soon be going stage 3 with dynomax resonator) and this was done months ago with no adverse effect (save for a bit of loudness only at certain times)

i always do regular interval changes of synthetic oil and change the auto transmisson fluid (oem) every three oil changes.

i'm planning on changing the air filter tomorrow as well as a fresh synthetic oil change 5w20.

any thoughts on this? and what ratings do you guys get normally?

any help/ideas/suggestions/opinions welcome and appreciated, thanks..

youngTL

Did your tire pressure go down because it's gotten cold out there in Ontario? That alone could be responsible for up to a 10% drop in fuel economy.

The other thing is cold starts. If you start cold, and don't drive very far, you get worse fuel numbers. The longer your engine is cold as a percentage of how long the car is running, the worse it'll be (so 5 minute trips are BAAAAAAAD!).

I normally get around 8.5 L/100km in mixed driving. Around 6.9 L/100km strictly highway, and up to 11.7-13.2 L/100km while driving around in very busy slow traffic.

Mine's a Type-S 6MT.

silver_shark

Thanks for the quick reply youngTL, I have a remote start on the car, and already assumed the temp drop would have an effect but didn't think it would be that much. Also i don't find myself stuck in traffic that often.. Maybe I'll need to change my spark plugs too.. I'm just over 140k right now. I'd like to be as low as possible in terms of fuel consumption but I'd honestly be happy with 8 or 9L/100km Lol

polish_pat

Hey, Have an 05 navi and your "regular" numbers seem kinda high. My average after a full tank is 9 or 10L/100km. 90% of the way is either 70, 90 or 100kmh zones. We all know what city driving does but on the highway, this car sips gas. 2 years ago I took my TL to NYC, about 600KM one way. I knew gas was way cheaper in the US so I planned to pass the border with almost an empty tank and full it first thing. To my surprise, the station had 101 octane fuel, i've never seen higher than 94 in Canada, and only Petro Canada has it i believe, but 101, I didnt even know existed.

Long story short, I was able to drive all the way to NYC and close to half the way back, with some light driving in NY, for a grand total of just under 900km. I was so surprised I swore I had an issue with the floater in the tank, or my needle not working. Some time after, I had to go get some parts at the dealer and asked the head machanic and he wasn't surprised at all, he even told me that I probably drove a good portion of the trip below 110km/h and he was right, the entire way there, it was a wierd mix of drizzle, light rain, a few minutes of nothing and it would start all over which meant I was always on cruise at about 110km/h. He said the TL has a sweet spot for the best km per tank and its at 107kmh. He said if we maintain that speed, the car drinks about 5L/100km. The guy clearely had knowledge about the car, but I still didnt believe it until I tried it myself.

This screenshot was taken on my way back from a long drive up north.

thoiboi

air pressure as suggested, new fall/winter blend gasoline perhaps,

lead foot..


there are a lot of variables and possibilities. You mention spark plugs. Were they not done at 105K along with your timing belt..?

Jackass

I was also going to say the winter blend fuels may be part of it...just not sure if your region changes drastically or when they may change. I know our blends usually start changing out in the Sept/Oct time frames and my MPG drops a few.

What has impacted my MPG over the years:

- tire pressure (1-2 MPG depending on how low or high I inflate them)
- tire choice (2-5 MPG depending on what tires I had)
- driving style (1-10 MPG depending on how much of a jackass I am being)
- driving location/speed (1-10 MPG depending on AVG and Top Speeds)

Changing my air filter, oil, and spark plugs did not change my MPG by any noticeable amount on my TL.

polobunny

Winter grade gas has not arrived in southern Canada yet. It's usually November at the earlier through March at the latest.

silver_shark

pressure had gone down when it first got cold, but i dealt with that over a month ago, and lead foot kept to a minimum.. lol bitching about gas/efficiency is redundant if that were the case, lol. I haven't done the timing belt service as of yet, i'm still at 140xxx KMs, if i'm not mistaken, 105,000 miles = ~165,000 km.. however i'm thinking i should do this soon as this is technically the 7th year for the car.

thanks for the info polish_pat, your numbers are good and that screenshot is bitter-sweet in the sense that i now know these cars can be that efficient, just bitter that mines isn't lol.

polobunny

My L/100km jumped up a bit too with the cold. It's all normal. I averaged 9L/100km a month ago or so, now I do 10L/100km. Colder starts + colder temperatures + heating can do that. Don't minimize the importance of the colder climate.

vpasla1

I've been averaging about 9L/100km with mixed driving, but I can usually get closer to 6.8-7.2L/100km (calculated by hand) with mostly highway driving (115-120km/h). I haven't even gotten close to hitting 5L/100km though, would be nice lol. I only used Top Tier 91 Octane gas (mostly Esso).

thoiboi

American problems sort didn't realize it was KM

polobunny

7L/100 km sounds about right. With ~100-105 km/h that's what I'll get, no matter the season. Once your car reaches operating temperatures it's pretty good, it's the cold start that kills mileage.

The most efficient speed for the 5AT is around 80 km/h for that matters. Please don't drive that speed unless it's the maximum limit, you'll get honked at.

polish_pat

I concur. The tech from Acura said best speed/gas consumption is 80kmh and best highway speed/gas is about 105. I was also told that above that, it drops dramatically, by as much as 15% per 10km.

I remember reading a Consumer Report article about easy, but taken for granted, ways that could save hundreds on gas per year, besides obviously regular car maintenance life filters and oils. In the tips I remember, there was:

using narrow tires, they might look awful but offer a lot less drag
Never fill tank to more than half because it adds 30Kg to total mass
Using alloy wheels, or generic, or rims that are made for light weight materials
Use the cruise control as much as possible, even if you're on a the highway for 1 or 2 km, or using a low speed long country road
Avoid braking + increase braking distance. If you have MT, dont downshift when coming up to stop sign or red light, put in neutral and use breaks
In winter, don't preheat the car before leaving. Modern cars only need about 1 minute of engine on to get the oils flowing. Preheating is the worst because it takes a very long time to really heat up and uses a lot of wanted fuel when the same job can be done in 1/4 of the time of slow driving.
Obviously driving habits are also the biggest factor

Every small tip gives between 1-3% fuel economy, but in 1 year, when you've spent 2000$ on gas, saving 15-25% comes up to a lot of money.

CenturionTL

Reset your ECU.

From your engine fuse box, pull 2 ECU fuses and the back up fuse.

Wait 15 minutes and put them back in.

silver_shark

thanks for the input guys. Centurion, i'll try resetting the ecu tomorrow. is this safe to do given that I have a remote starter on the car?

polish_pat

The ECU has nothing to do with remote starter. All programming is on starter control module and bypass module.

Although, just to be sure you don't reset the settings on those devices, I would try resetting the ECU using the gas pedal method. Done this already, I'm not sure how much it really impacted my driving quality, but hey, it can't harm

Clint08TLNAV

I'm sorry I wanted to contribute to this thread but the metric system just BLEW MY MIND.

polish_pat

Haha, welcome to what the entire planet has been using for ever. Oddly enough, there are some cities in some states that use the metric system...not sure why Americans stuck with imperial units...so much more complicated, so much less logical.

Turbonut

iTrader: (1)

Plugs nor air filter won't make a difference.
I don't have a remote starter on the TL as it's not used in the winter, but on our 4 cyl knock around car the mileage will see a drop of nearly 4 mpg when using the remote in the winter, @ 18% drop.