Got A Fuel Economy Shift Light?

AKA atomicalex

See the little arrow on the instrument cluster below? Right up at the top center. There’s a yellow LED in there that lately, I’ve been trying to keep off as much as possible. It’s the one leftover of the last gas crisis that I think we need to bring back: the fuel-economy-based shift light. If you have an early-80s VW or a mid-80s Plymouth Horizon or Dodge Omni, you probably recognize this feature. It uses a vacuum signal from the intake manifold and some simple relay-driven electronics to to indicate when you could be driving in a higher gear, and prods you to upshift by lighting up the arrow. I find that mine works pretty well, but it can lead to driving a lot harder than you would think possible for fuel economy. To keep it from lighting, you have to be at idle or close to WOT. The light is locked out in the top gear. I’ve been fooling around with minor tuning tweaks for the past couple of weeks, and combined with judicious minding of the light, I’m up to 30mpg in some really bad traffic. If I ignore the light, I drop down to about 27 or 28mpg. Considering that this is a 1.7L engine in a 2100 pound car, that’s not all that fantastic, but I am pretty impressed that the light does what it sets out to do—guides me to driving more efficiently. I find that I miss it when I’m driving my wagon, although the boost gauge on that car does a fair job as long as I stick to the algorithm—idle or WOT, no in-betweens. Do you have a car with a fuel economy shift light? Post up!

Permalink:

Posted at 6:57 pm in Gas, Guest Blogger, Katherine

Comments

kevin gosselin
Jul 21, 2008 at 3:27 pm

I was thinking this exact same thing today. My 88 BMW has the gauge which is very linear and makes a great connection between throttle input and fuel waste. Unlike my 2002 audi that has a digital gauge and jumps around a lot and it is delayed a few seconds so that the input you get from it makes it hard to drive efficiently.

I think all cars should have the BMW type sweep analog gauge, when I follow it, I get 3-4 more MPG.

James
Jul 20, 2008 at 3:03 am

I don’t know whatever piece of shit car that is, but my 87 Mercedes Benz I used to own had not a light, but a full on economy gauge with redline and everything. I only pushed it to about 1/3 of the gauge to keep gas consumption far down. It had a 5.6l V8 so the gauge was very necessary.

I wish my 4Runner had one, but I can just go off the tach.

James
Jul 20, 2008 at 2:29 am

I wish my 4Runner had one, but I can just go off the tach.

ram
Jul 13, 2008 at 8:02 pm

My uncle’s 98 Dodge Dakota has one….

Anonymous
Jul 11, 2008 at 3:24 pm

I do. 1991 CRX HF (the SLOW one that gets better efficiency than a Prius)

Scott
Jul 11, 2008 at 5:26 am

Good article to read. Very interesting.

iskander
Jul 11, 2008 at 4:48 am

On russian rides of 80s such as first gen Lada Samara was a special gauge indicating current fuel waste (like on bmw’s), so when you look at this gauge and drive the way to keep an arrow in the “green” zone – you can increase mileage, very useful gauge I think.

kansas coyote
Jul 11, 2008 at 4:38 am

my 03 Focus has it . .. It usually comes on just as I’m shifting (but I learned to do the fuel economy shift in my FIRST Mustang . .. )

Austin
Jul 11, 2008 at 4:29 am

My first car had one, an 89 Escort LX. I hated that stupid light. I now have a vacuum/boost gauge in my EXP and I find myself driving by it more and more.

Justin
Jul 10, 2008 at 11:50 pm

My 99 Neon R/T doesn’t have one. I wish it did, I’ve never drivin a stick before and I bought my neon and today was the first time driving it, I have a hard time shifting into first and for some reason I want to keep my foot on the gas when shifting into higher gears. Hopefully I get the hang of it, LOL. -Justin

Craig
Jul 10, 2008 at 7:29 pm

i do too, its a manny 94 SATURN sl2 and its at about 2300rpm and it lights at redline too so its like performance/eco light

uberaudi
Jul 10, 2008 at 7:23 pm

I had an ‘86 Audi Coupe GT that had a shift light. And my roomie’s ‘87 VW Scirocco has one too.

Anonymous
Jul 10, 2008 at 7:10 pm

Never saw that light in my own vehicles. Feeling out what is maxxed and gas bill over years (I am that slow to figure it out without planning to), light unnecessary. Boxers and inlines are bit different anyway. Boxer would have an upshift light on at 90% of the time, inlines are tricky. As a newb, I’d seriously use the light to drive the little inlines around. power curve is like 100rpm range after screaming through 8000rpm (I am not a fan of it- pun there..oh no…)

i_luv_dusty
Jul 10, 2008 at 7:04 pm

My father had an S10 that had that shift light, as well. ‘Course, his truck didn’t have a tach.

Personally, I find a manifold vacuum gauge to be easy to use. I installed one on my Ram, and I really like it. Just drive around maximizing the vacuum!