Insight gauges

[brekko]

I purchased a 2010 Insight a few months ago. After driving with my scanguage for several tanks I've noticed that the built in gauges for the Insight are not correct. The distance till empty always underestimates, and the fuel economy per tank always overestimates. I double checked this with by checking my per tank fuel economy the adhoc way of taking distance traveled divided by gallons filled up. Has anyone else noticed this anomaly?

[MetroMPG]

That's to be expected. It's more the rule than the exception that factory gauges are inaccurate.

Anecdotally, they usually underestimate fuel consumption. How far off is your factory gauge from reality?

[brekko]

Each tank the overall MPG will be overestimated by about 4-5% while the fuel consumption will be underestimated by about 10%. Unless this is just a safety feature to prevent against people running out of gas. It will read 0 Miles range left, while I will have between 1.5-1.8 gallons left.

[jamesqf]

Don't know about the current Insight, but on the Gen 1 Insight the ScanGauge is wildly inaccurate on anything to do with fuel, while the car's gauge is as close as I could readily measure - within a couple of percent or so.

[RedDevil]

The range left is underestimated (when near empty) for safety reasons, I guess.
You wouldn't want to fall short of fuel while it indicates there should be some left.

The fuel consumption indicated by the MID is less than the actual consumption calculated from the pump, but in part that can be explained by the fact that the Insight sucks excess vapor from the tank into the air intake. It cannot measure the amount of fuel that evaporates and gets sucked in, it only measures the liquid fuel it uses.

For every tank of fuel a tiny amount will evaporate, so there will be a difference even if all gauges work correctly. The Insight still burns the evaporated fuel, so the pump shows the real consumption.

My MID is 3 to 5 % optimistic on FE.

[jamesqf]

Originally Posted by RedDevil

The range left is underestimated (when near empty) for safety reasons, I guess.

And also, I would think, because the estimating is a fundamentally different problem. You could assume that your mpg would be the same as it has been for the last XX miles, but suppose you hit a headwind, have to climb a mountain, or who knows what?

The fuel consumption indicated by the MID is less than the actual consumption calculated from the pump, but in part that can be explained by the fact that the Insight sucks excess vapor from the tank into the air intake. It cannot measure the amount of fuel that evaporates and gets sucked in, it only measures the liquid fuel it uses.

But it should be able to compute that, and I think would do so as part of the emissions control system. It knows airflow and fuel injected, and has an oxygen sensor(s) in the exhaust. So X fuel + Y air should give Z O2. If it's more or less due to gasoline vapor, that's detected and X decreased in order to optimize emissions, no?

[user removed]

With modern in tank fuel pumps that are cooled by the fuel in the tank, when you run it completely out of fuel and even when you run it very low, both situations will accelerate the wear on the fuel pump.

I generally refill at just below 1/4 tank for that reason.

regards
Mech

[RedDevil]

Originally Posted by jamesqf

(about the Insight using but not counting gasoline vapor) But it should be able to compute that, and I think would do so as part of the emissions control system. It knows airflow and fuel injected, and has an oxygen sensor(s) in the exhaust. So X fuel + Y air should give Z O2. If it's more or less due to gasoline vapor, that's detected and X decreased in order to optimize emissions, no?

Maybe it could, but it would not know whether the enriched air is because of the recovery system or because of the overrich mixture of the car in front...
As it happens some G2 Insight owners have reported low FC readings just after filling and topping fuel. The most likely scenario is that their spills ended up enriching the recovery system, reducing the need for adding fuel in the usual way. Every now and then, after I fill up, it seems like the Insight runs almost by itself. The effect lasts just a mile or so.