Cold weather starts / increasing MPG?

[landspeed]

Hi!

I discovered a method that works on my old fuel injected car - just wondering
what people thought of it? (It only works if you have lots of gentle downhill gradient around).

When the engine is cold, the ECU enriches the mixture, hurting economy, and also, heat from combustion is sucked into the cylinder walls, reducing economy.

What I tried was, when the engine was completely cold, to accelerate, using 1400rpm max at each gear change, and then drive at 30mph, at about 1100rpm, coasting when downhill (to prevent fuel-cut), and using only a slight amount of accelerator pedal. My theory is that, the lower the revs, the longer the mixture stays in the engine to heat it up (rather than being wasted heat through the exhaust). Also, driving this slowly for the first 4-5 miles also means that you use less petrol (at a time when the fuel economy is very bad).

Any ideas on this?. Are there any better ways of cold-start warming up, without a block heater?

[kps]

Originally Posted by theclencher

http://www5.mississauga.ca/idlefree/facts.htm

Another city's 'anti- air pollution' web site. If cities actually gave a flying F---* about emissions, they wouldn't stick gratuitous stop signs every 20 feet.

*"Ford", of course.

[Spule 4]

Let me end the sentence:

Myth #2: Idling is good for your engine. Reality: Excessive idling can actually damage your engine components, including cylinders, spark plugs and exhaust systems

...when cars had carburetors.

[JanGeo]

I left a friends house one night and then proceeded up a long steep hill slowly at about 1000rpm in 3rd at about 15mph - it warmed up the engine to about 160 degrees - lugging it at slow speed seems to really work well and it didn't hurt the MPG much at all - will have to record actual info next time.

[landspeed]

I have found that this seems to get better per-tank MPGs, but can't wait till I get my SuperMID - hoping to break the 50MPG barrier (note that I am in the UK, so, my 50MPG is the same as you getting 45MPG). I get 48.5mpg on highways or on hilly country roads, and the official figures are 42MPG for highway driving. And this is with a thermostat that is not working well at all, and is seriously overcooling most of the time! (I know, I should fix it soon, just need to let it stop raining....)

I will post results when the SuperMID is available - but, I would note that by choosing a slower 12 mile route (back-roads), rather than a faster 10.5 mile route, my economy, and overall consumption, has improved dramatically!

[MetroMPG]

Are you going to use the Gas Log feature? It would be good to see your progress & recent MPG history.

[landspeed]

Is that a feature on this site?. I have the last 6 weeks of usage on a spreadsheet on my PDA

[MetroMPG]

Yessir. Go here: http://www.gassavers.org/garage/add

Add your vehicle details. Once that's in, you'll be able to add your tank-by-tank fill-up details to get a chart like this:

[landspeed]

How do I get the 'gassavers.org' signature with MPG on it? Do you have to make it by hand?
I have entered a summary of my data - will keep it up to date from now on. The problem is that I have to convert the litres - US gallons each time, so it would take ages to enter the whole database.

[landspeed]

done it