brettallica

OK, so I don't think this issue was ever really "resolved" - or at the very least, it wasn't thoroughly explained.

As those of you who have the navigation screen trip computer hack installed on your TLs know, the trip computer on the navigation screen (the one that you installed aftermarket) shows different numbers from that of the trip computer in the MID. I know a couple guys were thinking about running some experiments, but I can't seem to find anything that has to do with the experiment being run and/or any sort of finalization or closure to the matter.

So, I went ahead and did a little experiment of my own.

I did a complete fill-up, immediately after which time I reset the trip computer in the MID and the trip computer in navigation screen at the exact same time. I then drove the car to virtually empty (literally... and I know -- it's not good to do that, but I really wanted to get to the bottom of this) and took some snapshots of the relative screens (click to enlarge):



Glaring discrepancies between the two modules (MID and navigation screen):

• MPG: 21mpg on the MID vs. 22.4mpg on the navigation screen (white circles)
• Time: 9:57 on the MID vs. 9:41 on the navigation screen (green circles)
• Range: 4 miles remaining on the MID vs. --- (zero) on the navigation screen (red circles). The difference in range between the two was as much as 19 miles and as little as two miles, without any rhyme or reason; sometimes they were way different, and sometimes they were very close to each other.

What I simply cannot understand is how some of these numbers can be so different from each other. I mean, the times are WAY off; the MPG is semi-close; and the range was very sporadic with regard to being close to each other on each module. Perhaps the most interesting thing is that the "DIST" and "Trip" numbers came back virtually identical (within .1 mile of each other).

I'd love for someone to be able to come to a conclusion. The only thing that makes any sense to me is that there are two different computers being accessed to make these calibrations: the MID is hooked up to one, and the navigation screen is hooked up to another. Nothing else makes sense to me.

datmrman

For reference purposes, can you tell us which trip computer hack you used: patching the TL's HMIManager.exe or fooling the TL to use the Accord's trip computer?

Aznpersuasion

Nice write up I will have to try this one, and see what i came up with
~Jason

brettallica

I believe I used AngryDad's HMIManager.exe patch if memory serves me correctly. I had no knowledge of the Accord trip computer hack until now.

Cyph3r

Interesting experiment. For starters though I wouldn't worry or care much about the Range field with either trip computer as that can vary dramatically. The MPGs are close enough to almost overlook. However, what is of keen interest is the huge Time difference.

One possibility is that the MID is counting the minutes that the car is actually on and the trip computer hack is counting the minutes that you were moving? This of course could easily be checked by resetting both the trip computers and sitting idle in your driveway and see if the numbers count up.

The Range and MPGs would most likely be computed by two different computers with different algorithms, calculations and tolerances. So it'd be very hard to compare them 1-to-1 and get them to agree..

brettallica

Yeah, I'm not so much "worried" about the range on either. It's just interesting how some of the numbers can vary so much while others can be so close. I'm at a complete loss for the huge discrepancy in the time calculations. At first I thought the same thing you did, but I'm fairly certain that's not why it's different. I'll do another experiment on that one to be sure.

I'm just wondering: if one module is doing its calculations on one computer, and the other is doing it on another, which one is calculating more accurately? Logic says the computer the MID is using is the more accurate one since it's the one that comes standard on the car, but I don't know...the whole thing is just weird. I'm very tempted to try the Accord trip computer mod now.

crashandburn

If nothing else, this is a good indication of why Acura decided to suppress the Trip Computer module in the TL's navi software.

This may be a bit of a stretch but... do you remember about how many times you started the car during this test? The MID probably starts counting time as soon as the ignition is on but perhaps the Trip Computer doesn't start counting time until after the Nav system is booted up. If so, that could add a small chunk of time differential on every ignition cycle.