97 Civic Gas Mileage

[Unregistered]

97 Civic EX 2 Dr. 4 cyl,1.6 L
I have been having some gas mileage issues and I'm looking for a little help.

I was taking a road trip and filled up my tank 3 times when going out there. On road trips I usually average above or close to 300 mi/tank. The first, second, and third times I filled up were 260 mi, 315 m, 255 mi respectively.

I replaced my car's spark plugs, wires, cap and rotor last August. The filter is a K&N which I put in last July.

I'm just wondering if anyone has any suggestions for a fix?
Is this something I should ask the dealer about?
Should I try replacing anything myself before dealing with a dealership?

Thanks in advance!
Eric

[Unregistered]

Oh yes, and it was all highway miles. Very flat terrain.

[bmwpower]

The best way to tell your miles per gallon is to do a calculation. Simply clocking the miles until your next fill up assumes that you are filling up the tank from exactly the same level each time. A gallon or two more or less will throw off your total miles.

The calculation is easy:

- Fill up the tank.
- Clock the miles until your next fill up.
- Next time you fill up, note the amount of gas used to fill the tank.

Then,

Miles / Gallons = MPG

This assumes that the attendant fills up the tank to approximately the same level each time. In most cases, when the pump clicks off, you're good to go. Smack the kid if he tops it off.

[Mr T]

How many miles on the car? How big is your gas tank? (use the number listed in your manual).

With the numbers you gave, you are only off about 2-3 mpg..

How bout the PCV valve? Have you pulled the air filter to make sure its not plugged up with stuff... (hit any birds latley?) Have you checked your tire pressure? DId you have the AC on, or the defroster for long periods of time, as it cycles the AC compresser on/off.

Ive heard a few stories about the K&N filters (had one before, loved it), but if you over oil it, it will spray oil into some of your intake sensors (forget the name of the air flow sensor that ALL your air passes through..just behind the filter). But it can screw up that sensor... Shouldnt be a problem if your filter is still new, and you got 50-100k miles till you need to oil it (dont before 50k)

Has your check engine light ever come on?

[Unregistered]

Miles = 92,300
Tank Size Says 11.9 gallons, but the most gallons I've had to fill is around 10.
I pulled off my air filter and its not plugged up.
Havn't ever replaced the PCV valve (something I should do/check into?)
Tire pressure checked out at 30 which is what I'm told to keep it at.
I didn't need the AC on the trip, so that was left off.
I've never re-oiled my k&n.

Is the sensor your talking about is the Mass Airflow Sensor? Would these be expensive to replace? Is there a way to tell if it is going bad or is that a situation I should talk with the dealership about?

One thing I should mention is I was curious about getting some more power for my car a year ago or so and I got an AEM Cold air Intake free from a friend. It was cut off so it didn't go into the bumper like most. It turned out to be too loud and the wife didn't like it too much so I went with K&N. This intake was installed/uninstalled with the help of a mechanic friend.

As far as the other post. I did write down the amount of gas that was filled up each time and the mileage I had on the tank. It turned out to be around 24mpg for the 1st and 3rd fill-ups and 32mpg for the middle fill up.

[flickit]

Miles = 92,300
Tank Size Says 11.9 gallons, but the most gallons I've had to fill is around 10.
I pulled off my air filter and its not plugged up.
Havn't ever replaced the PCV valve (something I should do/check into?)
Tire pressure checked out at 30 which is what I'm told to keep it at.
I didn't need the AC on the trip, so that was left off.
I've never re-oiled my k&n.

Is the sensor your talking about is the Mass Airflow Sensor? Would these be expensive to replace? Is there a way to tell if it is going bad or is that a situation I should talk with the dealership about?

One thing I should mention is I was curious about getting some more power for my car a year ago or so and I got an AEM Cold air Intake free from a friend. It was cut off so it didn't go into the bumper like most. It turned out to be too loud and the wife didn't like it too much so I went with K&N. This intake was installed/uninstalled with the help of a mechanic friend.

As far as the other post. I did write down the amount of gas that was filled up each time and the mileage I had on the tank. It turned out to be around 24mpg for the 1st and 3rd fill-ups and 32mpg for the middle fill up.
...station for each fill up? Lotsa differences between stations and type of fuel, not to mention water content.

[Mr T]

If you havent oiled your filter yet, dont bother with the sensor.. I think it'l throw a check engine light /code out anyways.

Who told you to run at 30psi? What does the tire label inside your door say?

If you have a auto zone nearby, take it there. They can check your engine codes for free. Make sure nothing is logged.. Often that will cause your car's computer to go into open loop mode where it is running enough to keep the engine turning.

Your timing belt may need changed at 100k miles. How is the engine running.. does it spudder or seem to lack power? You could have jumpted a tooth on your timing...Enough to throw timing off. If that belt breaks, it will do very serious engine damage instantly.. hope you have plans to change it soon.

[Unregistered]

The label inside the door is 30 front 29 rear.

There is an autozone near by...do i just walk in and asked for them to check the codes? Its that easy?

My car is running smooth, nothing spuddering and I have as much power as my 4 cyl 1.6 L engine can give.

I do plan on replacing all my belts at the time of the timing belt change. I'd like to get on that well before 100k miles. Do you suggest any places to have this done? I've always went to Honda for my service, but if Autozone or similar shops are cheaper I'd be willing to do that.

Thanks

[Mr T]

I'd run your tires at what the door frame says to run at unless you have some special tires on it.

Some autozones will not admit they have the reader sometimes. Dont go there when they are busy or they wont read it for you.

I'd change the belt right around 100. If you drive it very hard or are in extreme temp's, have it checked before. Your manual will give a normal and heavy usage schedule. I would consider getting the water pump changed out too. Hondas are straightforward with their belts. Any local respected mechanic can do it for you too. Autozone will sell you the timing belt but they dont put them on. Check with the shop you go to before you buy belts elsewhere, some wont give you a warranty if you supply the parts.
Also look for specials at the dealers. Sometimes you can get it done very cheap. Dealer prices vary as much as your local shop, check all dealers in your area.

It sounds like you have all hte basics nailed on your milage. Only real thing left that you can do anything about is your driving habits. Otherwise it may be time to take it in.

[Unregistered]

Hey, thanks a lot for all the advise. I will be replacing the PCV valve this weekend and getting the timing belt replaced soon. Hopefully something works. Otherwise my younger brother is turning 16 in 6 months and needs a car :D

I will update you if something is fixed.