Instrumentation for Better Fuel Economy

Whether your reasons are financial or environmental, fuel economy seems to be a big deal these days.  Cruising for great gas mileage means fewer trips to the pumps, less mechanical wear and tear, reduced air pollution and, of course, saving money.

For some folks, getting a newer, fuel-efficient car is the answer.  But for many, getting a more efficient vehicle is not yet in the budget.  So, what can you do?

  • First, learn some basics about fuel economy, basic driving tips, hypermiling, ecomodding, etc.  I posted an introductory slideshow on it awhile back (it’s geared towards college students, but youl get the picture).
  • Next, visit my post on warm season driving tips.  Learn the tricks of A/C use, parking in the shade, NEVER idling.  By ‘adjusting the nut behind the wheel,’ you can tighten up your driving habits and maximizegas mileage for your vehicle.
  • Another tip is to consistently check your fuel economy.  Every time you fill up, keep track of your mileage, gallons of fuel, and cost.  You can keep a spreadsheet that tracks your fuel economy and cost.  Or, you can manage your fuel log online for free at a place like

Finally, invest in a real-time fuel economy (FE) gadget.  Knowing your fuel economy as you drive is a perfect training tool (which has already been incorporated into many newer cars (like the Toyota Prius–The Prius Effect).  I recommend the ScanGauge, which is compatible with most vehicles 1996 and newer with OBDII ports.  OBDII ports are usually located under the dash; a mechanic typically reads trouble codes through this port.  The ScanGauge plugs right in and provides several functions for you.

  • Digital display for multiple sensors (Coolant temperature, intake air temp, battery voltage, speed, RPM, etc.)
  • Calculates and displays fuel economy (instant FE, FE since engine start, FE for the tank, Gallons used per Hour, etc.)
  • Reads and clears trouble codes

Case Study: 2007 Pontiac Vibe (automatic)

BEFORE:  When I first got the Vibe, I was getting 26-28 MPG in town, and up to 33 mpg on the highway.  I was hitting the EPA estimate without any issue (and doing better than the new MPG calculation).  I was very impressed.

But in 2009 I found and and discovered what I was missing.  The first bit of advice almost everyone there gave was to invest in a ScanGauge.  Mine was about $150…which made me wonder if I’d ever get a ROI.

I installed my ScanGauge II in a cubby of my Vibe to hide it  (don’t want folks thinking it’s GPS and break in).

Now you see it, now you don’t!

AFTER: Since then, I’ve improved my fuel economy significantly.  Even around St. Louis with mixed driving/traffic, I’m averaging about 30 mpg per tank!!  I’ve hit highs of 38 and 40 mpg (per tank) on several occasions.  So, I’ve more than paid for my ScanGauge.

Why does the Scan Gauge help?  Because the real-time feedback trains me to monitor and adjust my habits.  It also becomes a bit of a game to compete with yourself.  I’m always trying to beat my best tank FE.  Best of luck to you!


Fair Weather Fuel Economy

The best way to save fuel, aside from purchasing a fuel efficient vehicle, is learning to improve fuel economy in your current vehicle by ‘fixing the nut behind the wheel.’  Minimizing fuel consumption takes work and knowing the quirks of your specific vehicle.  Luckily, as the warmer months approach, fuel economy automatically improves (decreased warm up times, warmer air temps, etc.).   But as warm borders on hot, we start using the air conditioning more often.  Cranking up the A/C (or rolling down the windows) can impact your fuel economy (FE), though by how much is debatable and varies by vehicle.   Overall, put windows down at lower speeds, and use A/C at higher speeds. (A good blog over the subject.)  Anyway, here are some tips to keep in mind during warmer weather.

If your vehicle has a recirculation function, use it in conjunction with your A/C to cool your car down faster.  This is known as MAX A/C, which counter-intuitively is more fuel efficient than regular A/C.

Once your car has cooled down to a comfortable level, with recirculation left on, power down your A/C for a while; turn the A/C back on when the air becomes noticeably warm again.  Your A/C really does decrease your fuel economy by 1-5%…so use it sparingly!

In the parking lot, do not linger.  Quickly find a parking spot and shut off your engine.  Park a bit further out and avoid the hassle of searching for a spot up close.  Or park in a central location and walk to nearby places (many stores are in strip malls).  Walking is good for you anyway.  Also, if you can, park somewhere in the shade to keep your car cool.  A shade tree or the side of a building may help.  Next, put up a sun shade to reflect light away from your windshield.  No need to bake your car’s interior and require more  A/C use.

Next, if you’re going inside, bring everyone in the car with you.  Leaving a car on with the A/C cranked in the parking lot gets you ZERO mpg and may put your vehicle at risk for overheating.  If they don’t want to shop (who wants to buy more clothes on a sweltering hot day?), find them a bench in the already air conditioned building.

Also, try to run errands in the morning or late evening when it might be just a little bit cooler.


Finally, these tips apply for any time of the year:

  • Coast as much as possible (downhill, yellow/red light, traffic)
  • Learn your routes and your stoplights (figure out light patterns)
  • Anticipate lights changing.
  • Run your errands with the furthest destination first, working your way back home.
  • Keep your tires properly inflated.  (Do not go beyond Max Sidewall Pressure on tire!!  And keep in mind that temperature changes effect your PSI)
  • In general, drive like your brake and gas pedals are hot as lava.  Use them sparingly. Learn how well your vehicle coasts.

For more, check out my slideshow on fuel economy.  Also, visit for driving tips and learn about ecomodding!