low mileage

2000 Accord v6 suddenly went from 25 mgp city driving to 18 mpg. Any
ideas why?

 

In order of decreasing likelihood IMO:

1. tire pressure
2. cold weather
3. change in driving pattern
4. winter fuel formulation
5. brake dragging
6. problem with engine

Of course, it could be a combination of these. Note that 1, 2 and 4
are related to weather. (You can now tell me that you live in
Southern California.)

 

Winter. The engine runs on "choke" for longer. In severe cold your
engine's "normal" operating temp may also a be a few degrees lower than in
Summer so slightly less efficient.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

What??

I don't think so.

 

If you can explain what it is you don't agree with I'll try to help.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

I know my car is running a little cooler these days...started up in five
seconds of cranking this morning, though, at -30C (-21F).

Shocks like rocks,
Seats like stones
Ride's so hard
I can feel it in my bones.

You're welcome. Coffee will kick in soon, don't worry...
Steve
Ottawa

 

The point of a thermostat, which every car has, is to regulate the coolant
temperature regardless of engine heat output or ambient temperature. If the
air temperature is colder, that's just a little bit less open it will be, as
more heat is radiated away from the car per unit time (or volume of
coolant).

Empirically, I've never seen the temperature gauge in any car "level off" at
a different point in the summer versus winter.

 

He's right. The block, head and rad lose heat much more rapidly in cold
weather. The greater the temperature difference, the greater the heat
transfer.

Basic physics.

 

After running your car for a good few miles in extreme cold, check your
radiator - it'll be stone cold and that cold air hits your engine straight
on. Add in the heater use and your thermostat will be closed most of the
time in extreme cold. Here's an experiment: with an ambient of say -10C
(not even that extreme), drive the car to warm the engine up and then let
it idle for 10mins or so, with the heater near high and the fan on position
2.

The usual mfr installed engine temperature gauges are calibrated with a
plateau on the temperature curve - the needle will show the "normal" temp
over a temp range of ~10C around the "normal" engine operating temp.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

I think it would have to be pretty darn cold that the thermostat would stay
entirely closed, and the cooling system wouldn't reach operating temperature
and would lose net heat under load. A lot colder than 0F or -10F.

When I had a '90 Grand Am a few years ago, it reached about -15F one day
during the winter, and yes, it did start to cool off at idle. I don't doubt
that this can happen, as I've seen it myself. However, once I started
driving again, the needle moved right back to where it usually rests.

That's the only time I've ever seen that happen. At 14F (which you're
giving as an example, with the heater on) I've never seen any car cool off
at idle.

Never heard of anything like this. This claim seems suspect to me. Got a
source/spec sheet or anything?

 

Don't know about Hondas but Volvo has used this in the past and may
still do it. It was a separate little board plugged into the larger
board in the instrument cluster. When it failed (which it usually
did), it could be replaced with a little jumper which would make the
temp gauge better-than-new, i.e. more sensitive to small temp changes.
The purpose of the board was to damp out minor fluctuations in
temperature readings around the normal range thereby reassuring
drivers that everything is OK.

 

Interesting.

My mom's '95 Bonneville temperature gauge is just the opposite. During
steady speed highway driving, the gauge will move slowly, alternating
between a higher and lower point. The thermostat control must be pretty
coarsely grained.

 

Interesting.

My mom's '95 Bonneville temperature gauge is just the opposite. During
steady speed highway driving, the gauge will move slowly, alternating
between a higher and lower point. The thermostat control must be pretty
coarsely grained.

 

What - you think that your car engine, with its crude mechanical temp
regulation system, runs at the exact same operating temp in -10C weather as

Yep - that's what the car mfr wants you to see - saves a lot of aggro at
warranty time. See below.

Every car I've owned has had noticeably reduced heat from the heater - more
than can be accounted for by the lower temp of the incoming air - in
extreme cold... it figures. As Tegger said, it's simple physics. BTW if
you want to discuss scientific fact, I'd suggest you use scientific units.

Now after your initial brain fart, you're haranguing - that's harrassing
based on ignorance. I refer you to the Honda factory service manuals
available from www.helminc.com. Specifically, the needle response is flat
between ~85C and ~100C and this is built in to the gauge... as well as the
usual and obvious damping.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

....

Is this where you found out that a 2000 Accord V6 had a choke?

 

Christ the brain farts are coming thick and fast here. Since you seem to
have a problem with written English, let me point out what I said was the
engine runs on "choke" (with quotes in the original text). If you do not
understand what this construction means I'd suggest you first, take a
course in English and then, one in automotive terminology.

Now if you ask nicely, and quit with the cerebral flatulence, I'll even
give the page number(s) and manual(s) where I found the graph of needle
response vs. sensor measured temperature.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

....
Wow, I already thought you were being offensive, but now you blaspheme the
name of my Lord and Savior. Thus are your true colors revealed.

I guess you believe that by putting quotes around a word, you can make up
any definition of the word you like. However, the word choke generally
refers to restricting air (thus the term "choke") and has no place being
used to describe a fuel injected engine in this context. Your use of this
term sheds doubt on everything else you have said here.
....

....
Assuming "Rgds" means regards, you should be putting this in quotes too,
since the word regard means to esteem and respect. Your language here shows
you have none.

 

<<snip>> of ignorant rant.

If it's a quarrel you want, please find someone else to do it with. I'd
suggest one of the alt.genius... or alt.bonehead... newsgroups, where I'm
sure you'll find people of a similar intellectual calibre to yourself and
who are more than willing to indulge your strange desire for exchanging
abuse.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

hehe, this one was funnny thread to follow -
dont stop now guys, it's just getting interesting

me??