Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - 1997 Honda Civic DX gets horible gas mileage?

Pendragon · 11-19-2012, 07:40 PM

Just a couple of things in addition to the good advice you have received so far.

Is there black smoke coming out of the exhaust and does it smell "rich" (gasoline odor)? If might very well be an O2 sensor, but could also be a temperature sensor. Either one of these should show up as a check engine code. There is also the possibility that the throttle body needs a good cleaning. (How does the engine idle?) There is also an EGR assembly that could get "gunked up" and could affect mileage.

I would also suggest checking for a dragging brake. Just jack the car up and spin the wheel by hand. It is also possible that one dragging brake could make the car pull to one side or the other either just going down the road or when braking.

I strongly second the advice about checking into the maintenance history of the timing belt. If you can do this yourself, you can save a lot of money. Make sure to check if the water pump is supposed to be changed at the same time as the timing belt on your car...I don't recall about your particular model, but many of the Hondas do.

Oh, about the Seafoam or BG 44K. Run it through the gas tank a couple of times just to make sure you have the fuel system good and clean. Thereafter you can do it periodically as preventative maintenance.

And when you are doing the tuneup, make sure to replace the fuel filter as well as the air filter. Make sure to use the weight of oil specified for your car. Sometimes people put in oil that is too "heavy" for the car and it does not do any good.

I live in a hot part of the country and like synthetic oil. I notice you are in an area where it gets cold...the synthetic oils are good there too. Make sure to use only Honda approved automatic transmission fluid. Their transmissions are very particular about being fed "the right stuff".

Good luck!

11-19-2012, 07:40 PM	#10 (permalink)
Pendragon EcoModding Lurker Join Date: Jan 2011 Location: Texas Posts: 82 Thanks: 3 Thanked 6 Times in 6 Posts	Just a couple of things in addition to the good advice you have received so far. Is there black smoke coming out of the exhaust and does it smell "rich" (gasoline odor)? If might very well be an O2 sensor, but could also be a temperature sensor. Either one of these should show up as a check engine code. There is also the possibility that the throttle body needs a good cleaning. (How does the engine idle?) There is also an EGR assembly that could get "gunked up" and could affect mileage. I would also suggest checking for a dragging brake. Just jack the car up and spin the wheel by hand. It is also possible that one dragging brake could make the car pull to one side or the other either just going down the road or when braking. I strongly second the advice about checking into the maintenance history of the timing belt. If you can do this yourself, you can save a lot of money. Make sure to check if the water pump is supposed to be changed at the same time as the timing belt on your car...I don't recall about your particular model, but many of the Hondas do. Oh, about the Seafoam or BG 44K. Run it through the gas tank a couple of times just to make sure you have the fuel system good and clean. Thereafter you can do it periodically as preventative maintenance. And when you are doing the tuneup, make sure to replace the fuel filter as well as the air filter. Make sure to use the weight of oil specified for your car. Sometimes people put in oil that is too "heavy" for the car and it does not do any good. I live in a hot part of the country and like synthetic oil. I notice you are in an area where it gets cold...the synthetic oils are good there too. Make sure to use only Honda approved automatic transmission fluid. Their transmissions are very particular about being fed "the right stuff". Good luck!