Missing odometer data
 

When I shut off my ICE to do a power off coast, I turn my key to the 2nd position (ICE off, accessories on), hold it for 3 sec to allow engine RMP's to zero, and then turn it back to the 3rd position (ICE on, accessories on) in preparation for bump starting it at the end of the coast. In my car, when the key is in the 2nd position, the speedometer and odometer are off-line. So for each cycle of codfishing, I am losing 3 seconds worth of odometer accumulation. At 55MPH a car travels 242 feet in 3 seconds. On my trip to work I go through 33 cycles of cod at an average speed of 55MPH, for a grand total of 7920 feet of distance (1.5 miles) not caught on my odometer. On the way home I go ICE off 29 times (@60MPH) for another 1.5 miles of non-odometer distance. When I drive south through rural SC to Greenwood, I typically codfish 94 to 100 times (depending on the route) on the drive south and 74 times on the drive north, both at 45MPH. This gives 3.6 miles (south) and 2.8 miles (north) of non-odometer distance on this drive. When I add the total sum of 17 miles of non-odometer distance accululated during my last tank to the total miles of that tank, my mileage junps from 70.4 to 72.7MPG. So the whole time I have been codfishing, I have selling myself short, mileage-wise. Three seconds of downtime on the odometer doesn't sound like much, but if you do it 751 times over the course of a tank of gas, it certainly adds up. I guess that means I will have to go through the last few months worth of MPG data for my car and put in the corrected miles for those tanks.

Give your VSS constant power and see if that helps.

Or better yet get some kind of instaneous feed back equipment like a SMID. I loved to see what your limits would be:D

Oh snizzap, forgot about that.

You might also consider odometer error, mine's about 3% running the same VSS as you, :p

I give up, what's a VSS and a SMID?

Vehicle Speed Sensor. It has power, ground, and signal. My assumption is that if you give it constant power it'll give constant signal.

SuperMID, Dan and I have this device for our pre-obdII FE display, :)

Is the VSS the sending unit on the top of the transmission housing that has a 3 wire connector on it? Or is it in the dashboard behind the speedo cluster? The superMID will have to wait until I have a spare $150 to blow. Right now all of my discretionary car funds are going into aero mods.

It's the thing you mentioned on top of final in the tranny with three wires.

And groundhog funerals. :D

I see it paid off - the correction boosted you into top spot in the gas log AND gave you 2 tanks at 90+ mpg :eek:

Impressive. I'm jealous. Time to do my undertrays...

EDIT: and push the car more.