I recently purchased a 1996 Civic LX. The first fill up I recorded 25 MPG so I decided to put an intake on bc the filter was dirty as hell. I just filled up again and record 28 MPG. It seems to me that this car should be getting much better gas mileage.

Info about car: Has 131K miles on it, new fuel filter, new wires, unsure of plugs and it's a 5 Speed.

I took the car to firestone the other day for an oil change. They recommended I get the timing belt done and that the valves may need to be adjusted. Does this seem right? What can I do to increase gas mileage?

 

LX's should be getting better gas mileage, the EX's is another story.

Check the plugs.......super easy to do, esp if you just got it.

Do the cap and rotor as well.

Timing belt do it, if you do not know if the other owner did it, then get it done, valve adjustment honestly, I would have Honda do it not Firestone, as for the timing belt check around local dealers and see if they have specials for it.

 

EX's getting bad mileage? What now?

 

Not bad, just not as good

Ex is rated 25 city 32 hwy when new.

 

Full tune up and as they suggested check the timing

 

I have a turbo EX and I get 30 mpg in town beating on it...36 mpg highway. OP is either driving like a retard or needs a tune up. Tire pressure, check brakes for drag, plugs/wires/cap/rotor/fuel filter are some easy things to check.

If your timing is off the car will run like crap, I doubt it's that. Timing belt should be changed once already, do you have any maintenance record for the car? If it hasn't been changed yet at 131k you need it done ASAP.

 

if the ek engines were supposedly similar to the LX eg, it would be rated at like 29-35 mpg

 

+1 on full tune up with cap and rotor. Maybe even a seafoam treatment.

Seafoam works for me, before anyone bashes me for it

 

^ How are you using Seafoam? I've used it through the brake booster as a vacuum source, about 1/3 of the bottle. Changed the oil, and realized my car was puffing out tons of blue smoke. 100 miles later the rings were shot and oil consumption also went through the roof.

Sure the idle smoothed out and ran better, but I also started burning oil and smoking blue.

PLEASE check out this thread, he vouched for Seafoam like you did and later came back to edit his post.
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/guaranteed-way-increase-your-horsepower-10-minutes-seafoam-1502112/

 

Your O2 sensor may need changed as well. Sometimes it's bad but a CEL doesn't go on, so your ECU gets inaccurate inputs.

 

well, every engine is different.. Sometimes theres buildup of oil/carbon on the rings that help with the sealing. take away that seal and some blowby might occur..

I used it as instructed on the can (ie: Not driving the **** out of it while its in the engine and oil) and ive had pretty good success with it..

GM makes a product like this as well, i cant remeber the name,but its blue & you pour it thru the spark plug holes to clean carbon build up from the combustion chambers.

 

Original stock engine or swap? If swap, what is the engine number? Report the engine number here anyway, just to be sure; it is embossed on the engine front near the dizzy. About what fraction of your driving is city and what fraction is highway?

www.fueleconomy.gov gives 16 individuals' reports with the manual transmission. Average is 36 mpg.

If you have no records of when the timing belt was changed, then like others here wrote, change it. This won't help your mileage but it will prevent possible engine destruction (valve damage) via a failed belt. It is not uncommon for this to happen when a belt fails. You are better off at an import shop for the timing belt change. To ensure OEM parts, you can buy an OEM timing belt package on Ebay at a price that will be competitive with what any shop charges for parts.

Are the new wires OEM? Non-oem wires are generally known to mess up running some.

Concur with starting with
-- tire pressure (overinflate at least 5 psi)
-- manufacturer spec'd plugs and OEM wires
-- OEM dizzy cap and rotor. OEM ignition parts pay for themselves with greater longevity/more reliability.
-- Get either a Denso or NTK oxygen sensor from amazon.com for about $40. Honda uses either Denso or NTK. It is good preventive maintenance to replace the oxygen sensor after around 100k miles/ten years.
--PCV valve. Use OEM only. If the old PCV valve is full of waxy buildup, this may be thee problem.

Monitor mileage after doing all the above. More for Civics at http://sites.google.com/site/hondali...gasmileagetips

Valve adjustment is rarely needed on Civics, despite what the owners' manual says. I would leave the valves alone for now.

Do not take advice from Firestone, in general. Oil changes there are fine, but nothing else. Firestone will not have mechanics specialized in Hondas and will not use OEM parts in general, and these will make a difference. This and other Civic forums are way better for advice.

 

EPA revised ratings:

EX auto:

27 combined.

Stick
28 combined

http://www.fueleconomy.gov/feg/calcu...umn=1&id=12607

 

I don't know about you, but I've always gotten better MPG's than the EPA estimate.

 

that site also rates my ej1 civic as 28mpg when my brochure that came with the car states 29-city 36-hwy, and even at that, everyone here knows sohc engines always range mid 30s combined mpg

 

There is probably a difference on the EPA site for a lot of old cars, as I think they changed their calculations sometime in the mid 2000's. As for my 5spd EX, hasn't returned a tank under 30mpg in a long, long time.

 

Change your PCV, this made a surprising difference in my 99 Civic Lx, went from mid 30's prior to full tune up and complete fluid change to mid to upper 40's on the 2 lane highway's local and upper 30's to low 40's on the Interstates.

Use all OEM parts, adjust your valves, check tire pressure as well.

 

are you mainly driving highway?

 

Do you drive like grandpa lol

I drive hard and fast on my 96 ex auto and mixed driving I get like 25 or 26.

I am talking 80 to 90 mph on the hwy to work.

 

I'm pretty sure I put up a post yesterday but I don't know where it went. 80% of my driving is on the highway to work. 20 miles each way. I average 60-75 MPH, not sure exact speed bc I'm pretty sure my speedo is off.

I'm doing tune up this weekend to ensure everything is brand new on that end.

Car is a manual as well.

 

Do you drive like grandma lol

I drive a turbo Honda on my 1997 ex manual and pure city I get like 30 or 31.

I am talking 8 psi every time I drive to work.

 

You should be getting close to 40 MPG. What gas are you using? I noticed a big jump when I went to Exxon...the 10 cents you save by going to a crappy gas station isn't worth the 30-40 less miles you drive per tank.

 

I use hess primarily.

 

i have noticed that my car likes shell gas a lot more here in illinois

 

Heck I use Murphy USA gas with a little bit of Lucas Upper Cylinder Lubricant and get 33 with an auto (42 highway)
I AM running 1 degree advanced on my timing though...maybe makes it burn a bit more cleanly with that Lucas?
*shrugs*

OP may wanna check their air/fuel ratio...I know Fuel Pressure regulators don't normally go bad, but the diaphragm in mine crapped out and I got TERRIBLE gas mileage for a while before I figured out what it was.
Swapped it out for one from the junkyard and it runs like a charm ^^

Also, it may seem dumb and obvious, but the type of tire you're riding on as well as the pressure in the tires makes a difference too
Good luck!