TLTrance

In terms of gas mileage...

I know there are tons of these threads related to gas mileage, but I'd like to be a bit more specific.

What are you guys getting out of your 115K+ miles TL? I currently get like 230-260 before the gas light comes on, which is significantly lower than the 280-300 I used to get when my 2005 TL was only a few years old. (Both of these figures are for 60-70% city driving, based on my guesstimate). I used to get 375-400 miles on 85/15 driving. I somehow doubt I could get that close now.. probably 325 or so.

I know there are those that recommend doing a seafoam. There are plenty of those that don't. So I'm not sure what I should do here..

My basic question is: How do I get back as close to possible the mileage that I used to have? In other words, what is the main culprit and how can I fix the issue?

Undying Dreams

iTrader: (3)

Can you post some shots or info from your MID?

What's your average MPH? The lower the average MPH, the lower your mileage.

If that is what it used to be then it could be a bunch of different things.

Clean the air filter, fuel filter, tire pressure, there's a lot of possibilities.

TLTrance

For the last 4000 miles, it has been around 28mph on average. This sounds low, but we know that this also includes stop time (which technically is 0 mph, but there should be an option to account for this).

I actually happen to have a few pics from back in 2008 (car was 3.5 years old) where I was able to get 430 miles before the light came on, even though I was going on average 53mph. I even managed to get 250+ miles when the needle was exactly at the 1/2way point!

Let's say that I get the 19mpg that Acura claims is the city mileage. The gas light comes on at 13.3 gallons used from full at cut-off, so doing some simple math results in ~253 miles. Thus, I'm getting lower than this with mixed driving. I should say that sometimes I get only 215 before the light comes on...

cinobyte

Have you done a tune-up lately? plugs air filter ect? I noticed some sluggish issues and i ran a can of seafoam through my tl. I know I know some love it some hate it but I have always had good results with it. I have had small engines go from not running to running great after a dose... The car "i think" does better after a can.. could be my imagination though

one other thought since you are relying on the mid only and not pen and paper maybe you should reset the system by disconnecting the battery no idea if that would have any affect at all but its a thought

BeezleTL85

Plugs and air filters, also are you using the proper oil an gas? That last part may be a stupid question but a lot of derps do it

DeathMetal

iTrader: (2)

+130k miles, about 27 to 25mpg. NOTHING maintenance related, if anything, it's because I'm on 18" wheels...so...looks like you and I are somewhat consistent.

Plugs, filters, seaform, and lastly...TIRES, TIRES, TIRES. The SINGLE most critical factor in quality mpg, I have found is quality tires and alignment. After that, stop searching...you'll just drive yourself nuts.

ez12a

yeah, can you tell us what maintenance you've done lately? I'm guessing timing belt job and spark plugs have ben replaced?

BeezleTL85

That's me in the side of the highway right now


And this is what my mid says to me




Sad panda up in this bitch

nottingham

I have 128k miles on my 05 6speed and get consistently 27 mpg in 90% city and 10% highway

DeathMetal

iTrader: (2)

Shit like this is why I seldom post here these days.

Seriously, what the hell is wrong with you?

BeezleTL85

Not sure what your problem is but since you never post then why don't you elaborate?

BeezleTL85

I ran out of gas because i stopped and the gas stations 20+ (literally) pumps were all closed/covered in plastic. Disnt make it down the highway to the next. Oh me oh my so stupid of me.



Actually F it. I know another DIY you can do with LED's. Why don't you put one in your ass so you can see that stick that's up there

gwiffer

iTrader: (7)

That's good!

Are you running E10 or Ethanol-free (E0) gas? 91?

What kind of tires? 235/45r17?

What kind of engine oil? 5w-20?

paperboy42190

iTrader: (7)

I can get 32mpg from my 07 type s....286hp and I still get 32mpg on highways, how much more can a person ask for?! btw its not about how many miles you count on the MID, it's about the rate of consumption, that's what matters. Granted yes the amount of miles per tank is inversely proportional to the rate of consumption, but its much more accurate on your wallet to use the MPG for calculation purposes.

CLtotheTL32

iTrader: (3)

My 2004 is about to hit 124k and I haven't noticed a drop in MPG whatsoever.

My current MID reading shows an average MPG of 26 with an average speed of 33. That has no highway driving but no stopped city driving either. I live in the boonies of NC so I'm usually on rural 2-lane roads with speed limits of over 45.

TLTrance

First, the mileage that I'm getting is based on miles driven since last time filling up to full. In other words: Miles Driven divided by 13.3. I don't use the mid for my mileage calculations unless its a straight drive without much of any stops.

In terms of what services I've done: I did the whole TB + SP + Valve Adjustment thing at 105K miles. Air filter was just changed by me last week, but I've noticed the mileage drop even after the previous time it was changed 3 years ago (this sounds like a long time, but I've driven very few miles since 2009). I've never put anything but 91 octane (highest available in CA) in the car since Day 1. I've been filling up with Shell or Chevron only.

TLTrance

I guess I should check to see if my mileage is improving since the air filter change. I'll also check the tires. Somehow I doubt these are the causes in my case...

I hate cars

Still talking about airfilters increasing mpg and some crude estimated city highway percent instead of average mph to validate it, huh? Wow.

Mrtastygoody

iTrader: (1)

Don't have pics, but for the past 7500 miles (3 months lol), I have an average of 41 mph, and 25mpg. Not bad. Not sure how much is city driving, but I'm in socal and my daily commute had quite a bit of stop and go.

motoboat

iTrader: (1)

Im at 145000 and i still get between 28-30 on highway, 65+. Around the town it drops significantly though.

TLTrance

Well, others brought it up, but I'm personally skeptical as to just how much of a negative impact a dirty air filter would've had.

As for crude highway driving percentage being used -- I did actually talk about real mileage driven divided by actual gallons used, so this is as precise as it gets.

ArthurL

iTrader: (4)

Mostly highway is around 26-30mpg. Mixed with mostly highway is around 20-24mpg. Because of Sandy, I've been forced to used regular because that's what's around sometimes and I've seen a drop in gas mileage around 22-24mpg on the highway.

Acura_Dude

I've been following the thread and I noticed something. You recently had your 105K service done. Did you or the dealer/indy shop do the service? If it's the latter did they use the correct plugs and not cheap alternatives? Are the valves adjusted within spec? I was just thinking about that and decided to post on it.

Bada$$VTEC

iTrader: (1)

Not this thread again...

I'm at 103k now on my 05 6spd,and i have the navi hack done

last time i filled up my car showed 22.1mpg and 23.6mph avg

This is with about 90% city driving and i got 294 on a full tank (when the light came on).

On the MID it says 20mpg 22mph avg tho.

TLTrance

Acura_Dude:
I actually provided the SPs myself (NGK Laser Iridium, #6994). That said, it might be worthwhile to check into this again, including the valve adjustment. It is possible that a switcheroo happened, although I do trust this mechanic. Then again, you never know, right?

Bada$$:
I'm definitely not using the MID for mileage calcs. But IF I did, it currently shows 20mpg. The rounding is probably what is making it 20. Nevertheless, I just look at miles driven / 13.3 gallons used (when the light comes on). Light usually comes on around 230-260 miles driven. At the top end of this, the results in 19.5 mpg.

CLtotheTL32

iTrader: (3)

You're getting exactly the MPG that the TL is supposed to get.

TLTrance

That's if I'm driving 100% city, which I'm not. Also, what I'm getting is different from a few years ago, so something's clearly changed...

TLTrance

I should mention that I've driven 100% city before several times in the past years and a few years ago I would get 280 or so. Thus, something is different..

I know there are tons of gas mileage threads, but I wanted to see if aging is a natural and ubiquitous cause of reduced mileage. Clearly from the responses here people are getting good mileage still with older engines.

LaCostaRacer

A properly turned 'old' car should yield similar MPG as the day it was new. The old car has the advantage of being fully broken in and the engine is looser.

If you are getting 19MPG with an average 28 MPH on MID there is nothing to be worried about. Your car is running perfect. My car that has 52k miles does exactly the same thing.

Oxygenated fuel usually starts in November and ends in February for California- that usually gives you a 10% hit which is 'ballpark' what you indicated in your first posting.

I hate cars

This shit never ends. Miles per tank is not a valid way to compare mileage.

The mid is more accurate than doing it by hand.

Mechanical wear is a non issue at 150,000 miles. If the car is truly getting worse mileage, it's not from wear. It takes a huge amount of wear to see a measurable change in mpg.

Saying "100% city" means absolutely zero, zilch, nada. It is about as important as what you had to eat yesterday in regards to mpg. Average mph is all that matters.

Spark plugs make little to no difference as long as theres no misfire. Hell, I've used platinums and now regular old $2 plugs one heat range colder with no changes in mpg.

Airfilters can never and will never ever ever ever ever have the slightest effect on mpg. Not .00000000000001mpg, nothing.

Going by "city" and "highway" to describe driving conditions is why people think something is wrong when its not.

Suri Juris

Damn. I have 121k and only get 17-18 mpg max reading on my MID. what do I need to do to increase it. I use 91 octane gas.

I hate cars

I guess no one reads the thread before posting. Post your average mph and you will probably find your mpg is normal.

LaCostaRacer

Kudos to Undying Dreams for the 2nd post which requested posting MPH.

What's wrong with you other people who make these MPG claims, but offer no real data to correlate things? No MPH, no MID photo, no nothing. What happens when you're on the highway and have 10 miles of stop & go traffic at 5 MPH- how does that compute in your summary- probably 100% highway right?

The MID is dead accurate based on my 6 years of experience. I have more faith in the MID's accuracy than people's 'math' skills claiming the MID is inaccurate.

There are many factors that will affect MPG, but some major ones are average speed (especially in 'city' driving) and the fact that some states are using oxygenated fuels now that don't pack the same amount of BTU energy as a regular gallon of gas. My car and driving style is so consistent that my Web browsers 'auto-fill' logic will predict my MPG. When I type 'MPH=28', the browser will auto complete 'MPH=28; MID=19MPG' because that is what has happened about 50 times in the life of the car. That's what I mean by consistency and the actual will be like 19.3 which proves the MID's accuracy.

TLTrance

No disrespect to anyone, but first off, the fuel light comes on exactly at the same point every time, yes? In other words, 13.3 gallons. So what exactly is wrong with computing mpg this way? It's not like I top off or fuel up the tank partially.

Also, my math skills are more than fine. But I do have a simple question: suppose you drive 60 mph for an hour. Suppose the mpg is 30 mpg during this hour of driving. Now suppose you stop but leave the engine idle. Do this for an hour. What is the average mph? The answer is 30. Do you honestly think that your mpg will be like 20 or 21 mpg? I bet if you let your car idle for an hour it would use probably a half gallon, maybe less? Say you use 1/2 gal. Simple math says the total fuel used would be 2.5 gal. The mpg therefore would be 24.

My point is that the MID is not telling the full story. Average mph isn't a great indicator of mpg when there is a great deal of slow or idle time. Average mph scales with time but mpg doesn't when idle.

The numbers above are just examples, but the principle I set out to demonstrate is sound.

TLTrance

Now, I forgot one thing. According to the AAA, 15 min of idling equates on average to quarter gallon of gas. If so, then the average mph would still be 30 above, but the mpg would be 20. This would still be better than my personal experience, which is why I'm questioning/asking this in the first place. I drive conservatively and honestly without being in a lot of stop and go traffic. Throw in steady freeway driving and I'm still getting fairly low mileage. Poor math skills or something else?

CLtotheTL32

iTrader: (3)

So you always divide your mileage by 13.3?

Whenever I fill up, I divide the miles I drove by the gallons of gas that I just got at the pump. That will get you a better idea of what your MPG really is.

Do us all a favor and fill up tomorrow. Take a picture everyday of your MID until your gas light turns on so we can see the stats. Then, divide the miles driven by both 13.3 and also by the exact number of gallons you just bought.

LaCostaRacer

All I can say is I have 6.5 years of data supporting the MID and the MPH correlation. While your example is plausible, it's more theoretical than realistic. Who in their right mind would idle a car for an hour after a 60 mile drive? The more realistic situation is commuting 60 miles on highway and then having a 'city' mode of stop/go traffic for say 10 miles and then another 60 mile commute home- no or little straight idle time but lots of creeping waiting for lights.

If you don't fill up each time, that's another glaring indication that your 'math' is suspect as well. I fill up each time and have not issues with the MID not confirming the 'math' calculation- the MID is integer so will naturally be off up to .5 based on rounding.

I don't rely on the light and it will fluctuate depending on grade of road and such- seems like it comes on with about 3-4 gallons left in the tank for my car.

ez12a

As CL stated, dividing miles by gallons filled at the pump is generally the accepted way to compute MPG, rather than relying on the light to indicate exactly 13.3 gal consumed.

Whenever i've computed the MPG at the pump, the MID was at most .1 mpg off, mainly due to rounding. I used to reset it every time I filled up.

ZOMGVTEK

I fill up at the same pump, at the same station every time. Run it until it clicks once, generally about the same time of day. The only thing that might vary is the density of the fuel due to the temp. The temp swings are probably not significant enough to matter much.

My last 3 tanks:

26.7 MPG (28MPG/27MPH MID)
27.6 MPG (29MPG/28MPH MID)
27.1 MPG (28MPG/28MPH MID)

So my MID is reading about 1 MPG high.

One interesting thing to note, is my Ultragauge reads about 25% less fuel consumed. It of course can be easily adjusted to this, but it was only a few percent off on my last car.

LaCostaRacer

^ those are extremely high reads for such low MPH. My MID would need to read 45MPH or higher to get a 27 MPG result. I just double-checked my www.fueleconomy.gov records and see that <30 MPH always results in a 19-21MPG performance.

I have had 244 fillups during the ownership of the car. There have been just 6 errors that are worse that .5 MPG which is pretty remarkable. My worst error was the MID reading 20MPG but the actual being 17.5. The other errors have been < 2 MPG difference where the actual is less than the MID.

Meanwhile, there have been 238 fillups that have had a dead-on MID to actual calculation allowing for the +/- .5 floating. I'm noticing that my MID will usually not round up until .7 (eg 18.7MPG => 19), so the MID is more conservative in its estimate.