Honda Car Forum

Hi Folks,

In January my trusty Accord has changed jobs - from off-peak runs to the
store and weekend trips, it is now my daily commuter. Work is just under 20
miles away - with 16 miles of expressway at one end, and residential
streets on the other end. I've been keeping track of mileage by the tank -
about 14 gallons from full to the light coming on.

Anyway, I've been getting around 24mpg. One tank I drove more or less as
gently as I could, upshifted early, cut my speed a bit etc. That tank I got
26.5mpg. It's better, but honestly it's not enough of a difference for me
all by itself.

Question 1 is for folks who have the same car: how does your mileage stack
up against mine?

Question 2 regards improvement: I'd be interested in minor modifications
(or maintenance items I've overlooked) that will improve the efficiency.
Decreasing cruising speed and accelerating more slowly are of course always
options, but I'm interested in something beyond that though. One variable
here is that the weather is getting warmer, so that will change my
efficiency somewhat by itself.


Some things I already know to do or have done:
o tune up items (done in Feb - included air filter, plugs, rotor/cap, valve
clearance)
o tire pressure (checked, ok)
o running temp (I believe it's OK, predictable gauge behavior right to
center line, and ample heater performance)

Any suggestions?

Arthur
Approaching 150k miles, 91 Accord LX sedan manual (2.2l F22A1)

--

P.S. Has anyone actually done what Ricky suggested below? I have a spare of
the check valve of which he speaks, I'm guessing the air pressure drop
across it provides the drop in fuel pressure he mentions.
But it seems to me that provided the system is still running closed loop,
the ECU will modify the injection timing to servo the O2 reading back where
it should be. I'm not interested in running open loop!

The excerpt is from a related thread for these 90-93 Accords:
> From: Ricky Spartacus (rickyspartan@mailandnews.com) Subject: Re: 91
> Accord fuel economy troubles View: Complete Thread (22 articles)
> Original Format Newsgroups: rec.autos.makers.honda Date: 2002-02-07
> 01:21:44 PST
>
>
> I have a magic simple solution. Remove the one way check valve from the
> cruise control vacuum tubing and install it between the FPR and the
> intake. Remember to plug up the cruise control tubing. This reduces the
> fuel pressure by about 15 psi. This equals to a moderate fuel savings
> at low speed cruising.
>
> -RS
>

I'd make sure that you aren't shifting TOO early. Lugging an engine will
give you worse fuel economy, not better. Also, when you change the plugs,
use NGK or ND. And if you need to change the cap, rotor and wires use the
Honda parts. (they are cheaper than the after market stuff and there won't
be any question about too high of resistance). While you are adjusting the
valves, pull the timing inspection plug out of the tranny and make sure the
timing belt hasn't slipped a tooth. I'd also set the timing and base idle
speed. Cleaning the throttle body couldn't hurt either. Also having the
injectors cleaned, either on the car or off could make a large difference in
mileage. I would think that car should get close to 30 MPG with a lot of
highway driving.

>
> Anyway, I've been getting around 24mpg. One tank I drove more or less as
> gently as I could, upshifted early, cut my speed a bit etc. That tank I
got
> 26.5mpg. It's better, but honestly it's not enough of a difference for me
> all by itself.
>
>
> Some things I already know to do or have done:
> o tune up items (done in Feb - included air filter, plugs, rotor/cap,
valve
> clearance)
> o tire pressure (checked, ok)
> o running temp (I believe it's OK, predictable gauge behavior right to
> center line, and ample heater performance)

Arthur Russell wrote:
>> Anyway, I've been getting around 24mpg. One tank I drove more or
>> less as gently as I could, upshifted early, cut my speed a bit etc.
>> That tank I got
>> 26.5mpg. It's better, but honestly it's not enough of a difference
>> for me all by itself.
>>
>> Question 1 is for folks who have the same car: how does your mileage
>> stack up against mine?

>> Arthur
>> Approaching 150k miles, 91 Accord LX sedan manual (2.2l F22A1)

I drive a 92 Accord, 2.2L, 4 CYL, AT, with 153000 miles as my daily drive,
about 15-20 miles a day generally. I get about 25 mpg city and about 30 mpg
highway when i go out of town.
With a MT, you are getting less mileage than my AT, so something's surely
wrong. I don't use any of those after-market STP, etc all-in-one system or
fuel-injector cleaners.
I use NGK plugs, if that helps.

I have a '91 Accord automatic with 215K miles and it gets about the same gas
mileage as it did when it was new; city 20-24mpg, depending on the season
and type of driving, to 29-30 on the highway (steady 70 mph). You city
driving component is where you are taking the hit. If you are getting 20
mpg in the city and 29 on the highway, using your percentages that's
5+21.75=26.75. Not much different from what you report. How agressive do
you drive, how up&down is your highway component? spending a lot of time at
stops/lights. Take the car for a 100+ mile highway trip and see how it
does. If it's in good shape and tune, you should get 30ish for an automatic
and 32+ for a manual tranny at 65-70 mph.

Lugging will hurt your mpg's. A good shift range is 3000-4000 rpm's. You
won't lead the pack, but it will get you decent mpg's and help the longevity
of the engine (think like the airplane mechanics do: wear is directly
proportional to engine speed).

I have used ND, NGK, Bosch and Autolite platinum plugs with all giving about
the same results. The last set went 80-90K miles with no big change in fuel
economy when they were changed. Regular plugs aren't rocket science.

Is your air filter clean?

Injectors can be cleaned up a bit by running a few tanks of premium through
the engine. The increased octane won't make any difference to your engine,
but premium fuels generally have better additive packages than regular. One
of the symptoms of dirty injectors is rough idle and or poor acceleration.

Try inflating your tires to 35 psi if you haven't already done so. The
honda spec for air pressure is a compromise for ride quality.

A dirty or clogged egr will affect mileage (and idle) as well as a faulty O2
sensor (which will trip the check engine light--but if it's starting to fail
may not have done so yet. Many people replace the O2 sensor after 100K
miles, I still have the original--go figure.

Gas mileage can change substantially with the seasons. If you live in a epa
clean air non-compliance area (any major city or downwind of one) the winter
fuel blends give lower mileage than the summer blend. Ethanol blends, 10%
or so alcohol--see major city comment, will also cut mileage slightly.

Use 5W30 oil all year, if you aren't already doing so.

Mileage is a sum of the parts thing. An mpg here another one there and soon
you'll be up to 28-30+.

Good Luck.
PS


---
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"Arthur Russell" <atr@bellatlantic.net> wrote
snip
> Question 1 is for folks who have the same car: how does your mileage stack
> up against mine?
>
> Question 2 regards improvement: I'd be interested in minor modifications
> (or maintenance items I've overlooked) that will improve the efficiency.
> Decreasing cruising speed and accelerating more slowly are of course always
> options, but I'm interested in something beyond that though. One variable
> here is that the weather is getting warmer, so that will change my
> efficiency somewhat by itself.
>
>
> Some things I already know to do or have done:
> o tune up items (done in Feb - included air filter, plugs, rotor/cap, valve
> clearance)
> o tire pressure (checked, ok)
> o running temp (I believe it's OK, predictable gauge behavior right to
> center line, and ample heater performance)
>
> Any suggestions?
>
> Arthur
> Approaching 150k miles, 91 Accord LX sedan manual (2.2l F22A1)

Have you ever changed out the PCV valve?

It's under $20 at most places. I changed mine out on my 91 Civic for the first
time at 140k miles. My mileage went up 15% to 20%.

Arthur Russell wrote:
>
> Question 1 is for folks who have the same car: how does your mileage stack
> up against mine?

I have a 1993 Accord LX automatic Canadian model, which is similar to the
American base DX model. The best I have gotten on the highway is 36mpg, but
I usually average 32-34mpg. This is with the cruise control engaged.

"Caroline" <caroline10027remove@earthlink.net> a écrit dans le message de
news:lAvjc.11749$eZ5.6990@newsread1.news.pas.earth link.net...
> > Approaching 150k miles, 91 Accord LX sedan manual (2.2l F22A1)

..(...)
> Have you ever changed out the PCV valve?
>
> It's under $20 at most places. I changed mine out on my 91 Civic for the
first
> time at 140k miles. My mileage went up 15% to 20%.
>

Hi,
Apolgise for my question (i'm French...)

What is PCV valve for?..

Thanks.

Philippe

Philippe M?RY <mery-ph@-discret-ifrance.com> wrote:
> Apolgise for my question (i'm French...)

> What is PCV valve for?..

Positive Crankcase Ventilation.
Unburned hydrocarbons that "blow by" the piston rings can be found in the
crankcase of older cars. The PCV valve draws the vapors into the engine to
burn them.
At one time there was a thing called a "road draft tube". The blow by was
vented under the car so that the fumes wouldn't bother the occupants, but
unburned hydrocarbons are a gross contributor to visible air pollution.


--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5

Both you and PS mentioned shifting too early. It certainly could be true
since the Owner's Manual lists "shift speeds for maximum efficiency", and
if you follow it you end up shifting from about 3k to 2k each time. I'll
try a tank or two shifting at their points.

For the record though, I'm not lugging it. I'm not interested in excessive
detonation pressure/fractured crowns and/or premature clutch wear!

....

I've been shifting earlier for two reasons: the first is the fairly well
known BMW report done some time back (that was a bit a of a surprise to
some folks) that said, as I understand it, without lugging it, maximum
efficiency is attained by shifting as early as possible. Previous to this,
apparently folks had thought the best thing to do was to wind it way up.
This updated philosophy seemed to have been adopted in the shift schedule
of my old 88 Camry - an efficiency aware car.

The second reason is that for me, shifting early is a way to keep the
responsiveness down a bit. This makes it less tempting to give it more gas
(since the response isn't very exciting anyway). Yeah, I should ease off,
but DAMN - I love the 3rd gear in this car all the way through the rpm
range, and 2nd gear at about 4k is pretty fun too.

So anyway, even though shifting early has improved the situation somewhat,
I'll try the shift points in the manual.

Thanks,
Arthur


Jafir Elkurd wrote:

> I'd make sure that you aren't shifting TOO early. Lugging an engine will
> give you worse fuel economy, not better. Also, when you change the plugs,
> use NGK or ND. And if you need to change the cap, rotor and wires use the
> Honda parts. (they are cheaper than the after market stuff and there won't
> be any question about too high of resistance). While you are adjusting the
> valves, pull the timing inspection plug out of the tranny and make sure the
> timing belt hasn't slipped a tooth. I'd also set the timing and base idle
> speed. Cleaning the throttle body couldn't hurt either. Also having the
> injectors cleaned, either on the car or off could make a large difference in
> mileage. I would think that car should get close to 30 MPG with a lot of
> highway driving.

Andy M --Tampa Bay-- wrote:
> I drive a 92 Accord, 2.2L, 4 CYL, AT, with 153000 miles as my daily drive,
> about 15-20 miles a day generally. I get about 25 mpg city and about 30 mpg
> highway when i go out of town.
> With a MT, you are getting less mileage than my AT, so something's surely
> wrong. I don't use any of those after-market STP, etc all-in-one system or
> fuel-injector cleaners.
> I use NGK plugs, if that helps.

OK, thanks for the data. It sounds like I have you beat, or at least we're
real close. I'm getting 25-27 for my mix of city/highway commute, and
though I didn't mention it I get more like 31-32 on the highway. For
sustained travel at 75mph cross country in the summer (2000 miles back in
1996) I pulled closer to 35 (it was long ago, and that's only from memory)

You might (still) be right that something's wrong though. I also don't use
aftermarket stuff. Plugs are new at last tuneup - I guess I can ask what
they used (but I'm not sure I'm sold on the spark-plug effect!)


------------------------------------
Sir Lointip wrote:
> I have a 1993 Accord LX automatic Canadian model, which is similar to
> the American base DX model. The best I have gotten on the highway is
> 36mpg, but I usually average 32-34mpg. This is with the cruise
> control engaged.

This also sounds in line with what I'm getting. If I'm in situations where
the cruise control is usable, I get 31-34 or so. My best might be 35, again
from distant memory (we have a nicer car for long trips now...)

-------------------------------------


Thanks again,
Arthur