MPG/Fuel Consumtion Issue...brainstorming ideas..???

[001Stunna]

there has to be an inefficancy between the engine and the wheels thats casing you to have bad mpg.

auto or 5MT? if auto, is it working well. MT is clutch slipping? do you rev to 6k every shift?

dragging breaks? check pad and shoe wear. check e-brake

worn wheel bearings

low compression. do a compression test. could be blown rings...does your car burn oil? any oil in your coolant ie. blown headgasket

The car is a 99 accord lx with abs, 4cyl and autotragic transmission.

Its driven pretty close to grandma style, it'll go wot maybe once a month lol...except that usually max it'll hit is 3krpm. After doing the seafoam its actually been even better regarding engine rpms. At 120km/h its at about 2.5-2.6krpm.

I've actually checked the brakes and they seemed ok to me...the rear drums are tightened to the point of 3/4of a free turn if spun. Parking Brake is fully engaged after 6clicks

As for wheel bearings i've checked spinning the tires and there is no humming.

As for compression, that one i have not done. But the car does not burn oil, and ive never found oil in the coolant.

 

[ryan s]

people just get fewer MPGs in the winter...in colder climates, i mean.

its also the winter gas with extra stuff. and ethanol additives. and the "reformulated" gas with additives. http://www.epa.gov/oms/fuels.htm

do you idle the car while scraping/brushing it off?
do you let it idle for 30 seconds every morning before driving?
do you spin the tires in the snow?
do you notice the transmission shifting slower, letting the revs go higher?

etc...all the small stuff adds up.

in the winter, i'm lucky to get 300 miles from ~14 gallons in the city. that's with smaller tires, so my actual MPG number is probably around 18.

 

[001Stunna]

people just get fewer MPGs in the winter...in colder climates, i mean.

its also the winter gas with extra stuff. and ethanol additives. and the "reformulated" gas with additives. http://www.epa.gov/oms/fuels.htm

do you idle the car while scraping/brushing it off?
do you let it idle for 30 seconds every morning before driving?
do you spin the tires in the snow?
do you notice the transmission shifting slower, letting the revs go higher?

etc...all the small stuff adds up.

in the winter, i'm lucky to get 300 miles from ~14 gallons in the city. that's with smaller tires, so my actual MPG number is probably around 18.

-Idle the car about 30sec-1min in the morning (It's parked outside all night long)
-No spinning tires in the snow.
-Transmission usually shifts below 3k rpm.

I understand the effects of winter gas. The thing is this started well before winter was here, it started since summer time.

 

[ryan s]

people say i drive like a granny but the car rarely shifts below 3500rpm

i'm not a pro mechanic or anything, but it sounds like it's a fuel system issue. pressure regulator...injectors...egr/gas cap/fuel pressure-holding/evap stuff...pump...could even be the ECU, perhaps? cheap or bad gas clogging the system?

we also need to keep in mind that just because something is "new," doesn't mean it's "good."

if there's a gas smell, i'd have to guess it's something with the fuel delivery. have someone test the injectors for you?

 

[lithiumus]

You said something about an aftermarket Cat... maybe get a proper OEM cat in there. Clogged or improper fuel injector spray pattern, dripping injectors. Fuel filter is a PITA to change since it's part of the pump assembly but worth a replacement if you've never done it. Vacuum leaks?

I think pretty much everything has been covered in the thread. My 4cyl used to get around well over 500km in the winter on a full tank and well over 600km in the summer on average.

Fuel system - pump, filter, regulator, injectors, vacuum hoses.
Ignition system - battery, distributor, plug wires, plugs
Exhaust system - o2 sensors, cats, egr

Have you gotten an emissions test done? See if they will allow you to put your car on the dyno and do a test or monitor run and let you see the HC, CO, NOX and AFR values when the car idles and cruises. At the same time hook up an OBD2 scanner and take note of engine temp, o2 sensor readings / activity.

Most Honda techs will first start with "is everything OEM?"... o2 sensors especially. Not saying that they are the problem but a lot of Honda techs will want to know that OEM sensors are in there. If the cat is not performing and the o2 sensors are telling the ECU to compensate, it could manifest in poor fuel consumption, failed emissions, etc.

You can try everything but until you can see the data (AFR, HC, CO, NOX along with the OBD2 data and o2 sensor activity) you won't really know what's going on. Can't troubleshoot without feedback from the car. If you don't know what it's doing, you'll won't be able to definitively address the problem. You may fix it by chance and trial and error but why not do a proper diagnosis.

 

[cloud9x]

i ran that canadian tire fuel injector cleaner (it's on sale now for 4.99!) and after 2 applications (every other fillup) i've noted that my MPG has gone down from 11.8 l/100km to 11.1 l/100km, consistently, through the winter.

that's about 576 km to the 64L tank. that's with nearly a 5 minute warmup every morning and evening after work. not too bad for winter, i must say. it'll look better in the summer, i'm sure.

so try the fuel injector cleaner chit if you haven't yet. good luck fellow torontonian.