wesleychan18

Hi all,

I don't know if there has been a question about this before, but I have a 96 Civic EX Sedan and I was getting around 35 MPG combined. Seems after this winter, the MPGs aren't the same.

Now, I was wondering what you could do to keep fuel economy really good, whether it means doing simple maintenance things, or perhaps doing some bolt-on mods.

From some friends, I heard that Seafoam-ing the engine is a good idea. Also, an air intake of sorts is apparently good. Perhaps there is something to do with the body to keep good fuel economy?

This just was a question I kept asking myself, so I was wondering what you guys do to keep good fuel economy.

I'm not too good with all the technical junk, so newbie language please.

Thanks in advance.

Smash03

I'm not expert, but a simple tune up should keep a good fuel economy on your car. Changing air filter, motor oil, fuel filter, spark plugs...things like that. I don't know what else you could do. Anybody else care to jump in...?

wesleychan18

Oil changes are done regularly as well as air filter cleanings or replacements. Last time we checked spark plugs, they were really good condition and my dad will never swap them out for nicer iridium ones, unless I do it myself. I don't think the fuel filter has been changed yet. What exactly do they do and when should they be replaced?

Linked

not only should you be replacing maintenance parts (you forgot the pcv valve, alot do)

if you dont know or havent recently done:

compression tests
leakdown tests
fuel pressure tests
wheel alignments
tire pressure

all of those, probably more, ensure that your engine is running efficiently and your getting the best performance/mpg you can

wesleychan18

PCV valve... means nothing to me, but probably means something to my dad.
Also just pumped up tires to optimal psi just the other day. Haven't done alignments recently and the first three I've never done myself, meaning I don't know how to do those. haha

xboxhaxorz

my mpg started suffering as well, than i started having alot of problems. my car started to feel very rough. nobody could figure it out. i think somebody mentioned a few filter on this forum, so got a fuel filter as well as a 3 part fuel induction done from merchants and the car is not a hundred times better than before.

i have just gotten it done so i havent driven enough to get the gauge my mpg just yet

hondamark35

there have been many threads on this topic so a quick search or two should yield good results.

i will add my personal experience though.. i keep my engine regularly serviced, free of leaks and properly adjusted. so i can't rightly comment on the effect that will have (though all the manuals say to do it for the best economy). however, of the handful of "upgrades" and changes I've made to my car only two things significantly effected the fuel economy (in a negative way): increase in tire size, and change in driving style/technique. (as a note: larger OE alloys with a wider more aggressive tire but no significant increase in mass)

96hb

The easiest way to get better mileage is to change the way you drive. Driving nice and smooth is best for fuel economy. No jackrabbit starts, use smooth acceleration, etc. Also I like to pump my tires up a bit more than most. I run like 40-45 psi in mine, which is still safe for my brand of tire. Just check the sidewall for the max psi. As others have said, do all the regular maintenance, filters, plugs, wires, etc. I like to run a fuel system cleaner once every oil change or so. Make sure your alignment is good. That could scrub off a couple mpg's. Check your timing and make sure it's ok, too. This is pretty much all I do on my bone stock y7 and I consistently pull 40-43 mpg.

hot92lude

Do they have a summer gas and a winter gas up there in canada?

thesmogman

I was hoping someone would mention this. There is a difference in summer/winter gas and it will affect mileage.

Ditto on the above mentioned. I would like to add, Every time you use the brakes you are losing mileage. So getting off the gas earlier also helps.

With your tune-ups you should check your timing.
Not just changing the motor oil but the tranny oil and your coolant. Make sure your car is running at the correct temps. (Thermostat)

Double ditto on the fuel injector cleaner every three oil changes.

O2 sensor, Depending on the age/mileage you should make sure it is operating properly. The O2 sensor is one of the main sensors the ecu uses to correct Air/Fuel ratios and can affect mileage alot.

OK I'm done.

Sr420Det

also up ur tires to a least the maximum pressure on the sidewall. I do 55 psi in all mine (50 on the sidewall). Kudos to ur dad who Im hoping is running cheap copper plugs and refuses to b sucked in the hype of iridium. Copper is the absolute best when it comes to plugs and they r the cheapest, it just doesnt last as long as the other high dollar materials. Drive SLOW. Got a z6 thats always getting around 40mpg

wesleychan18

Funny thing is I got combined 35 mpg with aggressive, smooth and highway driving. But I'm usually driving smooth and slow. Sometimes I even match speeds of slower granny drivers if I find them, just to **** off reckless teenage girl drivers who keep tailgating people.

Anyways, I just pumped tires to the recommended 29 psi rear and 30 psi front. That's recommended so I don't know if I should be exceeding that. Is there an optimal psi for fuel economy?

As for modifications, I heard that some could get you better fuel economy. Some people said CAI or SRI does??? I don't know... could someone confirm?

Odd thing is, I know there is different types of fuel for winter, but I just use the same stuff all the time... I guess you'd call it the "summer" stuff.

I really don't know if the tranny oil or coolant has been changed recently (I assume that those don't get checked over during a regular oil change). Thermostat recently got replaced after it died and caused a major coolant leak. All leaks are gone now, however.

Injector cleaning and O2 sensor check I have no clue how to do... I am seriously quite the noob when it comes to this stuff...

96hb

You need more air in the tires than that. That may be what's recommended on the inside of your door jamb, but look on the sidewall of your tires for a max psi rating. You should be able to go higher than 30. You should be able to go 35-40 psi no problems and I guarantee you it will help with your fuel economy. Hell I think even 29 is lower than what is recommended by the manufacturer. Most cars recomment at least 32 psi and that's mainly for comfort. Just dooo eiiit!!!!!!!!

Oh and injector cleaner is just something you add to your fuel tank at fill up. Check out your local auto parts store. There are many different brands to choose from. The one I use is Regane Fuel System Cleaner by Gumout.

thumper64

Chevron Techron fuel system cleaner is good.

The pressure listed on your door jam is the best to use. Less or more and you risk the tire being cupped in or out and not getting the best traction. I'd say go a few over, but that's it.

If you have a manual transmission, coast in gear to decelerate, but not out of gear. In gear the car will keep turning the motor, so the ECU will shut off the fuel injectors. If you're out of gear, the car has to idle and burn fuel.

A cold air intake can make the car more efficient, although increased flow and colder air will require more fuel.

EKb20p8r

I've heard of Prius owners using "hot-air intakes;" the idea is that by moving larger volumes of less-dense air you are reducing pumping losses (because the throttle body is open more for a given mass of air). I guess you would just run a duct to the back of the radiator. For better highway mileage, lower the car and install a splitter on the front bumper. For emissions purposes, the ECU is programmed to run an air-fuel ratio no leaner than stoich (14.6:1 I think). However, under light load, say cruising at part throttle, the car will run on mixtures as lean as 16.5:1 in some cases. The only downside is that you will produce a ton of NOx. I've seen rheostats for sale that hook up to the O2 sensor and modify the voltage coming from it, tricking the ECU so it thinks it is running 14.6 when it is actually running like 16:1. Since the O2 sensor isn't used during open loop there's no danger of running lean at WOT or high RPMs.

Linked

i've always coasted in neutral thinking i save more! thanks thumper,gonna try this new method right away ^_^

Duc_du

can someone please confirm this. i always coast in neutral

Red_Army

you'll slow down alot quicker too with it in gear.

but right now theres a good chance you've still got winter fuel at the pumps which has a bit more alcohol in it and in the summer would make you bog down and get the same or worse mpg as you do in the winter.

Sr420Det

Yes this is true. Ur injectors will turn off when ur in full vacumn. There is a technical name for this but pretty much all manuals work the same way. U will use NO fuel if ur coasting down while in gear. This is how all manual equipped factory ecu's work

thumper64

Look into what the hyper-milers do, such as putting diffusers, smooth wheel covers, wheel well covers like the Insight has on the rear wheels, etc. Some things look goofy, some aren't a big deal.

Lowering the car can help aerodynamics I believe, plus it will handle and look better.

I think the rheostat idea is not the best. Unless you know what you're doing, don't mess with anything that could make the engine run lean and possibly get preignition. You'll spend more rebuilding the motor than you'll save in gas.