88 EF Hatch

alright so i have posted this before... I have a 95 civic eg coupe with a obd0 b16a. It has brand new ignition parts but still seems to get poor gas mileage... i grandma drive the car and still only get about 10-20 mpg... its weird cuz sometimes a full tank will give me 140 miles and someitmes up to 240...... the only mods i have is an aem intake....and the car came with a huge exhaust.... looks like 3 inch piping all the way back....i dont smell my car burning to much fuel...no gas smell.... no black smoke.. so can exhaust be problem? what bout oxy sensors? help please

Aki Just Aki

Is your filter clean? That's a start.

iliv2xlr8

CEL's?
Stock cat?
Mileage on car?
How is the power?

Oxygen sensor can cause bad gas mileage, but typically when they are that far gone you get a CEL. I can't imagine a large exhaust would hurt your mileage that bad, but 3" is out of control for a stock B16.

alexbig6

have u checked your oil? most of the time when my gas mileage decreases i do an oil change and it picks right back up

brucepick

Check the ignition timing.
Not famous for causing mpg drop but I was surprised how badly mine was off - the last guy who set mine left it on maximum advance.

Make sure you get the right procedure for your year/version Civic

brucepick

Yeah - what's with that?
I seemed to notice it too but I can't figure why it happens.

Anybody got a clue?

FlewByU352

oil probally just breaking down and doesnt have the lubrication anymore and friction uses more power making your engine work less efficient. Which is why synthetic should always be used, increased power and oil life with it but all oil goes bad at one point.

Aki Just Aki

Yeah, but don't use synthetic if you burn or leak oil.
It'll only make it do those two faster.

FlewByU352

why is that? is the regular oil like sludging up and filling in the leak spots or something? I filled up my tank today and what a depressing site my gas is already so far down with just driving around town. I think for me its the driver and not the car. I just need to get it out of my system driving my car finally after it sat for months and finally having a 5 speed. I'll be doing good just shifting low RPM and then I see an open road and I hammer on it pedal all the way down banging gears. I figure by next fill up I should have most of it out and just driving regular... I hope.

Aki Just Aki

I suppose so on the filling up the cracks, but it's a bit thicker and doesn't seep through as easy. That's what a bunch of my friends said that work at oil change shops.

And I completely understand on the open roads. It's just too much fun not to go through the gears.

88 EF Hatch

its been doing it ever since i got car, and no CEL, and not sure on motor mileage.. and ill check ignition timing, and fresh oil change using royal purple

standbackimapro

Air filter, Fuel filter, have cat checked, bad or just shitty tires can cause bad gas mileage, bad alignment causing drag...

88 EF Hatch

there isnt a cat, and i forgot about tires ill check those out