2003 ZTS - horrible gas mileage - 16.3mpg - HELP

[PWGuy]

Originally Posted by sailor

Believe it or not (grin), it's actually better for the engine to warm up under light loads than to idle until warm.

Best way I can describe this, is that without any "load" on the engine, the moving parts tend to "flop around" more - creating stresses that aren't there in normal use.

Long times spent "idling" actually wear an engine MORE than normal highway driving for example, one of the many reasons "idle reduction technology" is a major issue regarding "Big Rigs" these days (Saving fuel & reducing emissions are the items in the news, but it does reduce maintenance & result in better longevity as well)

So for temps 50F and under, confirm if it is:

Light "load" > idle until warm > cold start and drive off immediately

[sailor]

Hah!

I see we've got varied opinions here, and neither is necessarily "wrong"...

The problem with short trips is that as a "general" rule, it takes a 20 minute drive or more to get the systems up to temp & burn off the moisture that results each time you fire it up cold (it's always producing moisture, but once warm it dissipates immediately).

Figuring a way to vary the use between vehicles so each gets some 'longer" trips on a regular basis is the most practical solution I've seen, Like when "Mom's" car would be used for the "Sunday Drives" so it would get a chance to stretch it's legs regularly...

The worst example of NOT doing this I've seen is on motorcycles that don't get driven in the winter. Some owners would "warm up" their bikes in the garage instead of winterizing them by draining the carburetors. By spring there were major deposits of tan sludge from oil mixed with water in the engine, you'll see the same on the oil fill cap of a car that seldom goes anywhere - especially in the winter.

Short trips are "severe duty" use for a vehicle, & I'm not sure that idle time to try to get it up to temp would be worthwhile in most cases for the reasons stated earlier.

My vote is toward varied use over trying to achieve a "full heat cycle" by excessive idling each time you drive....

Luck!

[Lscman]

Originally Posted by PWGuy

Ok, I will try warming up the car 5 minutes before my wife leaves to see if the mileage improves.

Thanks for all the suggestions

It will get even worse. Your car gets 0 mpg during the 5 min idle warmup and it will be running full rich. You have to drive trips at least 20 miles long before avg gas mileage will approach reasonable values. When your car is idling motionless it takes forever to warm up. Warm-up strategy is like pouring gasoline down the drain and the engine will wear more due to running cold so much.

Your gas mileage for such short trip sounds great. The alternatives include buying an electric car, walk or ride a bicycle.

[Lscman]

Originally Posted by IH84DZ

.......... a best practice would be to let it idle at least 10 minutes before driving especially in temps below 50*F. Granted, you are burning fuel that isn't moving the odometer so fuel economy will go down...but....you aren't really going to be impressed with your mileage if the car never gets warm enough for closed loop either........

Achieving normal operating temps (and closed loop mode) is indeed important for engine health. However bad gas mileage and engine wear issues will definitely NOT improve thru an idle warmup strategy. A car engine will consume almost as much fuel in 15 minutes idling as it takes to drive 2.9 mi cold....and it still needs to drive the distance. Gasoline engines consume lots of fuel at idle, especially when cold. Any car seeing trips under 5 miles each way is doomed to early demise. This car needs to see extended weekly drives for some other purpose to keep snot out of the crankcase.

[whynotthinkwhynot]

Did you ever recalculate your mileage based on how many gallons the gas pump says you put in when the light comes on?

250/ 14= 17.8
250/ 10= 25

I never put more than 11 gallons in if I catch it immediately when the light comes on.

[PWGuy]

Appreciate the perspective on the 10 minute idle - won't be doing that.

I haven't filled it up with gas yet to calculate the MPG - will probably fill it up this weekend.

[whynotthinkwhynot]

Thanks, keep us posted. Regardless of your mileage, I wish I only had to fill up every 2 weeks. We're weekly here- the wife drive half as much as I do, but gets roughly half the fuel economy. Here's another weird thing I've noticed recently. I picked up a 94 Corolla to drive while I do a clutch and other time consuming repairs to the Focus. My one way daily to work is 21 miles in the Focus, but 25 miles in the Corolla. That's a considerable difference for the same route. I blame tires, although I know the Focus is off- my speedo says I'm going faster than I am by 3 mph around 60 due to some construction radars in place on my route.

I look hard at fuel economy every tank in every vehicle I drive. I'd consider purchasing a plug-in electric vehicle in a NY min if I had the disposable income. Right now it's not cost effective for us to spend $6k/yr to save $3k. When the van goes, that's the route we'll take, but for now- arithmetic, right?

[VEGAS]

I fill up every 3 days, with 17mpg and a lead foot, jack rabbit starts... its funny tho, on my other car I get 330 to 350 miles to a tank.. and 170 with the other car.. LOL Between the 2.3L and automatic and lead foot with mods I kill the mpg.. But the near stock 2.0L Manual gets almost Double the miles..

[zx003]

2.9 miles to work one way. How long does it take for her to get to work? 5 minutes? Here in Washington DC, less than 2 miles most of the time will take you more than 10 minutes with city traffic, pedestrians and stop lights on every corner. Stop and go driving is a mileage killer.

[PWGuy]

Ok, an update - the tank was about half-emtpy at 103.3 miles. I filled it up last night to the FIRST CLICK ONLY and the amount filled was 4.940 gallons.

So I achieved 20.9mpg on the last 103.3 miles.

Now, I did take the car on a few extra jaunts around town out of necessity in the 103.3 miles without considering the affect on my test.

I also filled it with premium gas last night and the fill-up previous to last night.

Lastly, I removed the K&N filter from the stock airbox about 25 miles ago and added a Fram filter from Walmart.