People are free to enter any data they wish into the database. For my HCH the "by hand" results are always about 3.5% lower then the display shows. Personally I think the lower "by hand" numbers are more honest so I use the "by hand" method.

The Database has a check box for the method you claim to use. If you look at mine you will see:

Calculation Method: By Hand

The site owner Jason uses the other method so if you check his car out (down on the right side) you will see:

Calculation Method: By Display

 

I use hand also, Lakedude, and to backtrack to the 120 MPG thingy...it's odd but it brought to my attention the fact that the tanks of mine most heavily using P&G and FAS - meaning the tanks which in turn log the most miles over the 120 MPG max - have been my 25% you mentioned where hand is greater than display. I want to keep a closer watch on this for sure, and I'm curious if anyone else has had this experience. It would bode well for a PC glitch that caps calcs at 120 MPG.

 

Hi Helterskelter:

___In regards to recording beyond 120.0 mpg, the Insight did record beyond its max 150.0 mpg. When I head towards a particular exit of my sub, I have an ~ 3 block downhill coast. In the Insight from reset FCD, I would peg it at 150.0 immediately as I was only coasting to the stop sign while booted up. IIRC, it would take about 10 - 15 seconds of acceleration before the Insight’s FCD would finally drop below 150.0 mpg. Because of this, I believe it was holding digits well beyond the 150.0 mpg. The Insight also had a metric display that could measure much higher FE and that may be the reason it held that calculation? I am guessing that the HCH would do the same even though it does not have the metric display capability? Just a guess on the HCH?

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

That's exactly what I was hoping to find out Xcel, thanks. I'm really curious now - I'd love to try a trip reset on my HCH but my neurosis won't quite let me think about pushing the button on my LMPG Trip B display to give it a shot. Is there anyone out there who uses one of their HCH Trip meters just to track small jaunts instead of a LMPG that could give Xcel's suggestion a shot?

 

The problem is to get a sustaned 120MPG reading

 

Do you have any downhill areas like Wayne, even if it's just .3 miles?

 

I recently gave up using my Trip A meter for lmpg, because the spreadsheet I use keeps it as hand-calc'ed value (and the dealer accidentally reset it for me a while back). So I've been doing small jaunts with Trip A and find that the computer evidently keeps values above 120 mpg. Actually, I think the computer stores liters consumed since the meter was reset and combines that with miles since reset to get average miles per liter, then converts that to mpg.(see my next post) It doesn't average the instantaneous readings over time or miles. So if you're coasting with a dead engine and live electronics (is that "reboot?") there is zero gallons consumed and the instantaneous FE gets REALLY large. I have reset the meter at the top of a hill and pegged the FCD at 120 for a mile or two, then driven gently for a ways with the FCD at 80 for a similar distance and what did I get? Not 100 mpg which would be a reasonable average, but 119.9. Which tells me that the computer was recording VERY low fuel consumption while I coasted in neutral with FCD at 120.

Dave

 

Trip A, B numbers decoded.

The way that Trip A and Trip B meters increment by 0.3 or 0.4 mpg intrigued me from the beginning. It was easy to figure out that the Honda computer was dealing with liters instead of gallons because the conversion of 3.8+/- liters per gallon was familiar, having driven a ways in Mexico. I set up an Excel spreadsheet with one column for FE in m/liter, starting at 5.1, 5.2, etc. Up to 31.9 m/liter. Then in the next column, I multiplied those values by 3.785 to get mpg, which may run to six digits. The next column truncates the mpg to one digit past the decimal (not the same as rounding). And what you get is the series of numbers that Trip A or Trip B displays. Exactly. From 19.3 mpg for 5.1 mpl to 119.9 mpg for 31.7 mpl. I haven't observed all the numbers, but with spouse's help we've recorded about 80% of them and they all match. Has anyone seen 91.5 rather than 91.6 on their display? It's (91.5) the English equivalent of Honda's 24.2 mpl. OK, the procedure won't predict 120.0mpg, but there's probly another reason for that one.

It's funny what kind of activities being retired leads one into.

Dave

 

Though the HCH OSD tops at 120mpg, the acutal numbers beyond that are used, if say, you get 150 mpg. There are two reasons for me saything this, one logical, one physical:

1. The calculation you see is, just that, a calculation. The 120mpg is not "stored" and used in a future calculation. The computer (estimates) the fuel used and divides it by the mileage driven resulting in MPG (or whatever the calc is in the metric world). Thus, whether the last mile was driven at 0, 120, or infinity MPG (infinity is for those that use FAS), it doesn't use that data to caclulate the next reading. The computer just has a test for (IF MPG>120, then DISPLAY=120 ELSE DISPLAY=MPG); or some such.

2. One gas station I use frequently is at the top of a nice, long 1.5 mile hill. At about halfway done the hill, my Trip A (my tank mpg) will read 120 mpg. After my speed is reduced on the next 1.5 mile flat to 40 mph, there is a stretch where I must use the engine and my FCD shows 80-100 mpg. The OSD display does not immediately start tracking down. It takes another mile or so until I start to see 119.7, 119.4, etc. It takes a while to get from the 120+ mpg back down into real world numbers. I have managed to have the reading at 120 with the trip meter reading 7 miles.

Sound good?

 

Can some of the discrepencies be due to how you fill your tank? Do you top off? I filled up this morning and the pump auto-stopped at 10.59 gallons. I usually don't top off but decided to do it this time and I was able to get a total of 11.89 gallons in. That is a difference of 5.35 MPG on the 518.3 miles I drove on that tank. Depending on the pump, it may auto-stop at different times and that may result in 2-3 MPG difference. My hand calculated MPG (when not topping off) is usually about 1 mpg lower than what my display shows. With the top-off this time, the hand calculated MPG would be 43.59 MPG and my display showed 49.5 MPG.