I have a 2001 Honda Civic. It has had crappy gas mileage since day one. 20 city/30 hwy (and as low as 18 in stop and go driving) as opposed to the 30/40 other people get with this car. The “30 hwy” is on a 180 mile stetch of flat interstate on cruise control. Ideal conditions. I have talked to a lot of Civic owners about this. The Honda dealer has checked it twice. No problems with the computer or the emission data. The dealer tries to convince me that my gas mileage is within normal range, but I really don’t see how that can be true.
There is a raw gasoline smell generated in the garage when I first fire it up in the morning, but there is no ongoing smell, drip, or any other ongoing evidence of a leak, as far as I know. There is frequently a slight hesitation when accelerating from low speeds after the rpms have dropped down as in cornering.
Crappy fuel/air blend, poss related to the electronic engine mgmnt system, which should show up in an engine diagnostic.
If the mixture is off, and other settings, you piss away lot’s of fuel with little air, meaning poor combustion = low mileage…even some power loss and drivablility issues (hestitation, etc).
Get Honda to do engine/comp diaghnostic OR get an independent shop for a small fee.
<slight hijack>At one (if not more) of the auto accessory places-Checker/Autozone come to mind ,they advertise free diagnostic check.Would this shed any light or are they just for checking a bad part you need to buy?
My gas mileage seems to have dropped about 1-2 MPG this winter,compared to previous winters.That is roughly a 10% loss with no appreciable power loss as far as I can tell.
They’re checking for trouble codes in the electronic control system. It’s not a bad first step to take, but it’s nowhere near a complete diagnosis. For example, if the code description is “oxygen sensor not switching,” they would suggest a new oxygen sensor – which might fix it, if the code isn’t caused by a wiring problem or mixture problem or an exhaust leak or…
And yes, they do this in hopes that you will buy the suggested part from them.
Not all of it, but it’s part of it, and the first part to do.
At a properly equipped repair shop (as opposed to a parts store), they would use a scanner that not only reads the trouble code memory but also reads data from the computer. Often there are other features involved as well, such as “freeze frames” showing the data readings at the time a code was set, and test modes that actuate certain components to see if they respond properly to the computer’s commands. On the newer cars, there’s really quite a lot of information available from the computer when using a good scanner. Even so, unfortunately, not every problem will be revealed this way. Presumably that’s the situation in your case.
What kind of Honda Civic do you have vs. the “others” you mention? If you have a souped up EX vs. someone else’s economizer CX, you’ll see a real difference. Your 20/30 sounds about what I had on my '95 Civic EX 5-speed, but that was beating the hell out of it.
Hijack of a hijack: that’s most likely due to the air in your tires compressing (as much as 1 PSI for every 10 degrees farenheit) and the underpressure causing excessive friction. This would actually improve performance in some instances (i.e. “peeling out”), and hinder it in others (cornering perhaps). As a whole, though, you still lose significant MPG.
If your car smells like gasoline every morning, it’s leaking it some place. This is rather/somewhat/perhaps/moderately hazardous. Does your car share a garage with a furnace or a gas water heater? It could be atop the engine. It could be a fuel line; did you graunch over a curb? Many questions, one answer. Get it fixed.
They have been equivalent. Recent EXs. The last person I talked to had the exact same car down to the color.
AskNott , the car does not smell until I start it. It is not leaking in the garage. I would smell that. In othe words, the fuel does not leak away when the car is parked.
** seaworthy ** , I have a '83 Corolla with 180 k miles on it that gets 28 on the same stretch of interstate where my Civic gets 30!
Alert Alert This may be significant.
I just noticed an entry on the emissions test. There is an entry for “P.E.F.” with says “zero required”
** Hobbes **= Interesting.It has been cold the last couple ,3 weeks, and about when I noticed the lower mileage.
It’s starting to warm up closer to what I consider normal for this time of year.
I’m getting the oil changed tomorrow,when they check the air pressure,etc (“full service Jiffy Lube”),so I’ll run the tank to the warning light before filling then check * that * tankfull.
I rarely check my air pressure since the tires are only about 5k mi.old and they look fine.
Hey Galen, also where do you live? And do they have “winter” gasoline there? I always get crappier mileage in the Winter, because here in Michigan we use a different smog formulation gasoline.
hobbes730 – thanks for reminding me to check my tires :).
No, that’s not it. It is the same winter or summer.
Some more relevant facts.
There is soot, not much, but some, in the exhaust pipe.
The emissions test showed 23 ppm of HC. This seems waaaaay high. Anyone know what this should be? I checked some old smog test papers and I’ve had a '79 Corolla test at 10 and an '83 Corolla test at thirtysomething.
O2 in the exhaust reads zero.
This is supposed to be an ultra low emission vehicle (ULEV)