Fuel Efficiency got worse
 

I've noticed that my 1998 Honda Civic's fuel efficiency has gotten worse at my most recent fill up. used to get around 400-450km/38-40L. Recent fill up was 380ish km before filling up 38ish L.

-Primary O2 sensor, Distributer cap, and injectors was replaced last year at rise.
-Spark Plugs about 3 years ago
-Fuel Filter around 2 years ago
-Oil changed and oil filter about 3 months ago.
-Air Filter just a few months ago.

i may be forgetting something but in the 4.5 years i've had this car, i've only driven 30,000km, and have been doing oil changes and oil filter changes ever 6months, give or take.

Anything else I might need done to help out? Needle has dipped down a bit lower than usual for the 90ish km mark on my trip.

Advice would be appreciated. Thanks in advance!

check ur wheel bearings and transmission fluid. also might be good to check ur cat to see if its clogged

make sure also to change tire...new tire thread will save gas compared to bald tires. also get rid of items in car that will add weight.

check/clean/adj or replace the plugs

PCV valve!

Check tire presure. I had one tire @ 10psi and. It cost me $15 more
To do the same route

how can new thread save gas? wouldn't cause more friction = use more gas?

thanks for all the tips guys! unfortunately, im not sure i have the tools or know-how to do some of these things.

i do have new tires that was purchased november 2010 and havent been used all that much. and didnt have this poor of fuel efficiency during that time.

today on my way home from work i noticed a belt was squealing quite a bit during startup and continued even when i got home (10 min drive from a-b). not sure what to think of it. i do know my timing belt was done recent (around 198xxxkm, car currently at 204xxxkm)

Have you done a wheel alignment recently?

Cause when I did mines, fuel economy went up noticeably.

Less rolling resistance due to less rubber and harder compound stuck to the pavement. Quite often race tires are shaved for the exact opposite reason.
Many of the above are very valid reasons as well so check your tire pressure. In my Jeep if my tires are down to 10psi which looks the same as 30psi my mileage goes to shits.

Has your commute changed? 10 minutes doesn't exactly get your car hot enough to perform at its best. It's barely warmed up and then you shut it off. I wouldn't be surprised if there's significant carbon build up in the engine, your cat doesn't get hot enough to burn the extra fuel and the moisture in the exhaust just sits there.

the squeeling is your alternator belt. your short drive does not fully recharge your battery after startup demands and eventually the load on your alternator to charge a dying battery will cause the belt to stretch and squeel.

Hi, I'm in the auto industry and may be of some help.

Check and if required, replace your EGR. Clean any EGR galleries under the valve cover. Check your tyre pressures every 2-3 days. Not only can it help mileage, you can also spot any possible punctures. Do your alignment once a year minimum. no matter what.

I noticed the plugs were changed. What about the plug wires?
next oil change, do an engine flush on it to clean out any crap. Every 2 months, run a bottle of injector cleaner with a fresh tank of fuel, preferably 91 octane. higher octane fuel burns a bit more stable at temperature. Combined with the cleaners, can help remove some carbon cloggage in your systems.

This one's important: DRIVE MORE. If you drive less than 15,000km a year, chances are, that there will be significant carbon deposits in your systems caused by excess amounts of unburnt fuel, etc. due to the car not running at optimal temperature enough.

once a week, take it on the highway, and give it a good rip for about 15-20minutes so everything heats up and the fluids get flowing. A car's like a person. Don't work it out enough then when you do, everything starts to have trouble working properly.

Your car's a 1998. Chances are it's got a bit of stuff in there.

i'll take a look under the hood at the fluid. weather and work havent really been on my side lately :(

got tires just last year and i have a set of winter tires so i dont think that should be the problem

don't have the tools to do that i dont think. at least, not to adj them anyway

sadly i dont even know where that is, or if it's something im capable of doing. scared of screwing up

last time i checked they were good. i'll double check in the morning

i havent. whats the ball park price figure for a service like that?

within the past 6 months i'd say i've driven a little less? my old commute to work was about 15 mins each way. sometimes i'd go out but not all too often. since leaving that job, my commute to work is about 10 minutes each way, mostly just getting on and off highway 1.

how often does the belt need to be replaced? is it something that would affect mileage?

well, i just looked up what an egr is, and tried looking up something on youtube to give me an idea, but im not sure if its something i can do =[

plugs were changed about 3 years ago as i mentioned before. the wires... i can't say im certain, but i believe they were changed at rise when my distributor cap was replaced. and this was about a year ago

i'll definitely keep that in mind to take it out more. thanks! =D


Again, thank you all for your suggestions.. if anyone is willing to take some time and show me how to do some of these things i'll buy you dinner or something =D i'd love to learn how to do these things myself.

How's the thermostat doing? Mine was stuck open and lost about 50km per tank.

alternator belt squealing does not affect gas milage. to make sure its an alternator belt, squeal, pour some water or even spray wd-40 on the belt to see if the noise goes away. I would say take the throttle body out and give it a good cleaning and maybe the intake manifold too. Also try cleaning your fuel injectors, if you dont know how, you can try another method by filling up full tank of gas and pouring fuel injector cleaner into the tank. Like what typeRnammer said, maybe do an alignment if u havent done one before. usually alignment changes when ur spring sags down over time. one easy way to check is if ur steering wheel pulls to a side or not, but that doesnt tell u everything. check your tires for uneven wear pattern (negative/positive camber wear, toe in/out wear)

I can help you out with showing you around with your car. I'm also a bit of a weekend mechanic so I can teach you how to take certain things apart, and watch for signs of any issues.

You can call me up at 778-883-5489. Name's Dan.

This goes for anyone out there that requires a rundown on how car shit works, prices, what-to-look for, etc.

I've been in the industry for a few years, so I'm fairly confident as long as it's not luxury german or exotics (They require actual research and study with the dealer).

TypeR-nammer could vouch for me. A bit. LOL.

Your PCV is located right above your oil filter. Best done when you're changing your oil. It's as easy as popping it out, and putting the hose back on it.
How To: D16Y8 PCV Valve Change - ClubCivic.com - Honda Civic Forum

A lot easier than my WRX. To change mine, I have to remove my intercooler and get behind the throttle body :okay:

Have you Concidered it's summer and warmer out, so you will be rolling with the a/c on or windows down far more often, which will reduce fuel economy.

i don't use a/c for my car unless its absolutely necessary. otherwise i do have my windows down, but just in reference to last years summer, my mileage is worse this time around

thanks! i tried looking on youtube about that, but no full on video, just like... a slideshow so it made me a bit weary about doing it myself

i'll take you up on that! :D pm'd

as soon as i noticed the shitty mileage, i went and grabbed a bottle of the cleaner. hoping that helps a bit. looking forward to having a run-down with dan to learn more about my car =D

i.... wish i knew where to look... :okay:

http://yeow.com.ar/img/2012/03/goku-...me-140x140.jpg

Just kidding LOL

^ TypeRNammer = master of douchebaggery. LOL

OP: You won't be able to really see your thermostat. It's usually located where the main coolant hose goes into the motor. Someone'll have to point it out though because it's usually kinda hidden.

It could be just shitty gas. A bad batch more than anything else.

Driving habits change. Weather (humidity, temp, etc) is also a factor. Carying more shit in your car.......... g/f or you getting a little heavier. Your car is getting older. Like humans...... I ain't as fast or as efficient as I used to be. Just throwing more stuff out there...........

you should try the amsoil performance improver.. it cleans your fuel system and helps give better gas mileage! im using it and i love it