Hello I'm receiving only about 80-100 on half a tank. I wanted to know or pinpoint what is really causing this.. I have 49k mi on my car, its a 2008 GD3 5speed.

I have not changed these since I got the car:
Trannsmission Fluid
Coolant
Spark Plugs
Cabin Filter.

I'm due for a B1 and 2 check up. I know my MPG is bad but can all those really cause that huge of a drop in MPG? I normally get 160-180 on half a tank. I'm going to change all that this weekend. But what about the rest of the B1 inspection, is it worth the dealership inspecting?

 

I would make sure you have enough coolant and perhaps have the valves adjusted. I have 50k on my GD and have seen a small mileage drop I so far can only guess is due to the valves so I plan on doing them soon.

 

the dealer is going to drain your bank account!
1.) change the oil with 5/20 amsoil and WIX filter 4 qts and 2 filters change filter after 3500 miles the oil will go 7k.
2.) trans fluid with amsoil universal: drain the fluid in the pan and add 3.5 qts., remove the trans plug and IT will be tight from the factory ( I have a '08 and the plug is blue paint on it or dye)
3.) change engine air filter. I got a short ram off Ebay for 45.00 shipping incd. power increase and added mpg too! (pix on my site)
4.) buy STP injector cleaner in the red bottle 3 for 2.97 @ walmart : these come in 8 oz. bottles. buy a gallon of wd-40 @ home depot for 15.00 to a full tank of regular add one bottle of fuel injct. cleaner with 8 oz. of wd-40 the wd-40 will lubricate the uppper cylinder head and displace any moisture in the fuel system. I have been using this for 15k and average 32 mpg in town and up to 44 mpg fully loaded down with family and luggage on the highway.
5.) Try this first and use a good quality gasoline like Exxon b4 ya go and through a paycheck to the dealer.
Good luck my fellow freak
6.) if this drop has happen with in the last fillup check all the vacumm hose connection under the hood !!
7.) if the valves are out of adjustment that will effect the milage and performance. it's not too bad a task, it's like a math problem that is u don't go exactly step by step you will be way off @ the end of the proceedure.
Good Maintenice Practices = Less Headaches

 

I've got 61K on my 08 5sp and avg about 37mpg. Only thing I've changed are oil regularly and the engine air filter. If you haven't changed the engine air filter that could be the problem. Maybe the valves but doubtful - do they clatter? Does it feel like its making normal power?

 

My dealership doesn't charge anything extra for a 'B' inspection, but I've had all my oil changes there. They also do tire rotation with every other oil change for the same $26 plus tax.

No CEL?

Can't say PEBSASW on this one because it isn't a new car for you. I, too have noticed a drop in FE with my Fit over the course of the last year. It's getting harder and harder to maintain the 40+mpg mark. Of course, I'm driving a little more aggressively, too.

I have noticed that tire pressure makes a big difference with this car.

PEBSASW = Problem Exists Between Seat And Steering Wheel

 

My valves have been chattering probably since 20k miles and my mpg then was great 35-40. I stopped going to the dealer for oil changes for one because the prices have gone up for basic mineral oil, about $34.99. and they charge me for extra things like a new bolt, which i pay for every time and never have gotten and my bolt is almost stripped from lack of change.

Also I've changed the engine filter at about 30kish so its relatively new, i check it and it has a little bit of dirt but nothing abnormal. and i dont feel any loss of power.

Alssssso I've driven the car pretty hard and still did at least 27-32mpg and thats like going 80mph highway.

 

Definitely air filter! Never heard of WD-40 in the fuel... I don't know about that one.

 

I smell sabotage! lol jk. Does sound weird though. But man I've ran dirty filters with 80K on a CAI system on a different car and it never was this bad. Sadly enough I've used that filter on my fit with a home-made SRI and it still wasnt this bad.

 

I have a hunch both of our issues are the valves needing adjustment. Honda recommends adjusting them at 100k or so and I've heard from several people on FF that at that point they are way, way out of spec. Their recommendation was it could be done as early as 50k and make a substantial difference. Mine have been chattering since ~30k and I do drive the car quite hard on occasion as well.

 

I do a ton of driving. My car sounds like a diesel engine no joke. How much does this adjustment cost? I am skeptical that they will even do it. They charge so much for tiny things and usually never do them

 

To even get to the valves they have to pull open the head. It ain't cheap. It sucks too, because actually checking the valves for clearance and adjusting them is pretty simple.

I would not be surprised that one of the 'budget' items of these engines is whatever keeps the valves self adjusted, and wringing the engine out hastens the issues.

 

check your tire pressure, change air filter if you haven't recently, make sure you use 5W20. how's your battery?

go easy on the gas pedal.

 

I'm planning on doing the valves myself, as I understand it to be a pretty simple process with the right tools (cheap). The pain is getting the intake manifold and the head cover off, but it seems perfectly doable.

 

whats a good tire pressure? I'm on aftermarket wheels with 195/50. Air filter I will replace. Battery is still going strong.

 

Don't break 40 psi because that'll overinflate your rubber and make your tires' grip less effective. 37F/35R should be your maximum - that'll work well even if you flog the car on a track.

If you wanna dial in some comfort 35F/32R will work.

 

use techron fuel system cleaner...see what happens

 

Never depend on the indication on the tank gauge. How many trip miles divided by the gallons needed to 'fill-up' will give you a better indication. Other than that tire pressure 40 psi and if valves are chattering reset clearance. And surely you aren't having to do a lot of 3rd and 4th gear driving.

 

Are you 100 % that you are using 5-20 oil if not this could cause a hugh diffence in mpg .

 

i have 48,200 miles and i get 200-180 miles to the halve way mark always 5 speed 07 and i drive in nyc ever day ! 36-38 mpg

 

Yeah I'm using 5W-20 for sure. I've also even switched to higher quality gas which is the weird part. I'm at 40PSI right now. I will be changing the rest of the fluids this week.

I really want to adjust my valves but it sounds so pricey and I don't think I'm experienced enough to do it.