1990 accord - winter gas mileage

Hi all,

My 1990 Accord eats up a lot of gas this winter. I've filled up 9 litres
or so for ~65km. It's been cold outside about -10 to -15. I'm not idling
the car, just driving in town.

What should I do to get it to be more efficient. Last oil change was in
December.

thanks in advance,
-Vlad

 

You used 9 liters in 65 kilometers?? I would look for a leak!!! Or
maybe someone is siphoning from you!

Dan D
'07 Ody EX
Central NJ USA

 

Do everything listed at:
http://home.earthlink.net/~honda.lioness/id11.html

Take seriously the advice on using only OEM for ignition
parts.

 

I do a lot of intown driving - many rides short distances. In the
summer fuel efficiency is about 11l/100km in town.

vlad

 

That is about 15 mpg. I would suggest that there might be a lot of
error in the refill factor. You need to run it down to the last
quarter of the tank to get the best accuracy.

I am also wondering how many short trips you do. If you are driving
it 5 miles through the city making two or three stops (e.g. shopping)
along the way and then parking it for 10 hours or more then 15 mpg
might be about right at these temperatures.

 

About 21 mpg. Is the -10 to -15 degrees F or C? If it is F, then you
may be lucky the mileage isn't worse.

 

Yes, that figure is just over 21mpg for US gallons, which is pretty good
for all-city, short-hop driving.

Since the OP is in Canada, his temperatures are Celsius. -15C is +5F. Many
short trips in those temperatures mean extremely high fuel consumption.

 

Thank you all,

Yes, all my trips are 1-2 km to the grocery store and back at around -15C
in Canada. I never had these problems a few months ago when it was still
above 0.

Vlad

 

Sure..The choke/fast idle/ECU rich mix is going on longer until it
warms up.
Once warm, there shouldn't be a whole lot of difference. But when
cold,
they drink the gas. And if it takes a good while longer to warm up,
just
that much more gas.. If you do many short trips in the cold wx, it's
going
to drink more gas. The car barely gets a chance to fully warm, and
every
time you go again, the car is probably cold again, and has to start
over.
MK

 

This use is also very hard on the engine. There is going to be a ton
of condensation and unburned gas in the crankcase and exhaust. If you
are using the car this way, you should take it on a 20+ km drive once
a week and change the oil every 3 months.

 

Is it a better idea to idle the car for 5min before driving it?

-vlad

 

No. That's a BAD idea. You see people doing that, go up and give them a
smack upside the head. It's not good for the car to do that regularly.

It's a better idea to take the car for an hour's highway drive once a week.
This will get the oil hot enough to burn off all the water and gas that's
been collecting in it during your one-mile toodles to the grocery store.

An weekly hour's drive will also exercise the brakes, suspension and the
various seals, helping to prolong their lives and stave off trouble.

 

This has been asked before, but I have never seen a logical answer
provided (since I've been here, anyhow)...

WHY is it a bad idea? I understand that Honda recommends against it, but
what is the rationale? What is the negative effect on the engine from
idling for 5-10 minutes to get the heat going when it is 5 degrees outside?

I have taken to the habit of starting the car, brushing off the snow and
ice, and getting on the road, simply because Honda says so. I'd love to
know exactly why they say so...

 

here's what i've been told: 95% of all ring/cylinder wear occurs during
warmup. the longer warmup takes, the longer you're in the high wear
phase. an engine idling takes ages, an engine driven gets there quickly.

i understand that it's partly a lubricant viscosity thing and partly a
lubricant dilution thing because unburnt gasoline can condense on cold
cylinder walls and dilute the oil film. diesels, which have the same
factors involved, experience much less ring/cylinder wear because diesel
condensate is a lubricant, gas condensate is not.

 

Correct.

Extended cold idling periods dump tons of gas and water into the oil,
since the engine warms up so much more slowly. It takes longer full-hot
driving to boil all that off. This also contributes to sludge and
varnish buildup.

On the other hand, idling the car when it's already fully warm does not
cause the same problem, so that's OK.

The only benefit to extended cold idling is visibility: the windows will
be more completely cleared (if frosted up, that is), so you can more
safely see where you're going.

 

Thanks, Jim and Tegger, for excellent information...

I will continue to do as I have been... Basically warm it as long as it
takes to brush it off and defog the windows, then get rolling...