My on-board computer is very erratic when it comes to estimating my fuel burn - it is showing 38l per 100km. This is well over my actual fuel burn. Any ideas why my computer is giving these faulty readings?
Bad Fuel Economy - LC200
- Thread starter m00sekateer
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On vehicles the computer estimated mpg is often referred to as a GOM (guess-o-meter). It usually uses what’s called a weighted moving average that bounces around as a result of several different inputs. Running a stock setup with stock tires will usually get the closest to actual, but if you track mpg, you need to use the direct liters per kilometer calculation yourself.
I have tracked my computer mpg versus refill and calculate for every tank since new. The computer on my LC has not been more than .6 mpg off calculated over the last 129k miles. Really only the first tank or 2 at new had any significant deviations.
Road trip the past few days. Highway, city, mountain passes, etc. Cruising 30mph in town, 45-55mph on the narrow mountain passes, and anywhere between 70 and 110mph on the flats, and I'm averaging 15.1mpg no matter how fast or slow I'm going.
LvCruiserNewb
SILVER Star
Did you reset the mpg calculator prior to the road trip? It's a running average over the entire duration since you last reset it. So if you haven't reset it in 30,000 miles or however long it's the average mpg over that interval. To reset you press and hold the right hand enter button on the steering wheel while you're viewing the mpg display on the dash. I usually reset mine every fill up unless I'm on a long trip and want to see thr average from the whole trip.
Nice avatar picture fyi. That was a bad ass jet. And a great lesson in how terrible govt requirements can lead to sub-optimal designs that cost more $ to fix later.
I'll try that next time I top off fuel. I was just resetting the trip odometer.
Regarding the Phantom, the E/G model was well refined, and in certain applications, it was still more capable than the early models of the platforms that replaced it, especially in the Wild Weasel role.
Interesting. My fuel average calc machine resets after the fuel lever floater detects a fill-up. After every fresh tank, the MPG (US vehicle) resets. Also, if you have any mods that break OE aero or tire size, it's best to just calculate fuel consumption with your own data.
So I did the reset from the steering wheel, and it really didn't change my average much. Went from 15.1 to 15.0, which I attribute to the 120 I was doing passing a long train of vehicles that were afraid to pass a motorhome on a three mile long straight stretch at a slight incline.
I tried cruising at 70, 80, and 90, and it didn't appear to really change anything other than the wind noise increase with speed increase from the Yakama rack on top.
The 200 mostly felt right at home doing 90, as it was smooth as glass at that speed.
Last tank full, I was bucking a pretty good quartering headwind, and it dropped my average down to 13.1 until I got out of that. Now home and it's at 14.2
I tried cruising at 70, 80, and 90, and it didn't appear to really change anything other than the wind noise increase with speed increase from the Yakama rack on top.
The 200 mostly felt right at home doing 90, as it was smooth as glass at that speed.
Last tank full, I was bucking a pretty good quartering headwind, and it dropped my average down to 13.1 until I got out of that. Now home and it's at 14.2
I hope you don’t really drive a 6k lb LC 120MPH in traffic.
When calculating fuel economy, one has to do this multiple times and on consistent longer stretches of highway and average the results. There are too many variables even during mostly highway driving (long road trip), like head/tail wind, average speed, up/downhill, stop and go, tire pressure, outside temperature, altitude above sea level, type of asphalt, rain/dry.
Also topping off fuel tank can vary by up to one gallon, depending how sensitive the nozzle's stop mechanism is.
Also topping off fuel tank can vary by up to one gallon, depending how sensitive the nozzle's stop mechanism is.
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