"MPGiata" modding thread: aiming for 50 MPG with a 1990 Miata. Update: success, 55 MPG!

[Ecky]

What's wrong with your MPGuino?

I notice mine doesn't sleep, and seems to count up in both miles and gallons overnight. Not sure what's up with that.

[mpg_numbers_guy]

Originally Posted by Ecky

What's wrong with your MPGuino?

I notice mine doesn't sleep, and seems to count up in both miles and gallons overnight. Not sure what's up with that.

Does your car odometer change as well? If so, maybe something's up with the gauge cluster wiring that's not letting the speed go down to true 0 (maybe 0.1 or something).

[Ecky]

Originally Posted by mpg_numbers_guy

Does your car odometer change as well? If so, maybe something's up with the gauge cluster wiring that's not letting the speed go down to true 0 (maybe 0.1 or something).

I don't mean to get too off in the weeds in this thread, but no it doesn't. Both injector line and VSS are unpowered when the car is off so it's pretty bizarre. I might try intercepting the VSS before my converter box but I have no explanation for the injectors.

[MetroMPG]

Originally Posted by Gasoline Fumes

I never went as far as a chart! At least not on paper, maybe there was one in my head.

My head doesn't retain info that well.

I've done enough fuel gauge/odo-tracking now to make up a little chart so I know roughly where the trip odo should be at each tick mark on the gauge.

Sometimes the Insight's fantastic economy instrumentation drives me crazy. Too much info! I'm used to getting fuel economy numbers every 3-4 weeks

I miss Insight-level gauges!

Originally Posted by Ecky

What's wrong with your MPGuino?

It randomly reboots. It's rare to go ~30 km without a reset. Sometimes multiple reboots within a few minutes. Sometimes it even loses my calibration settings and I have to reset it.

[MetroMPG]

Mine also stays on all the time. I added a switch in the 12v wire... which is also useful because occasionally it freezes. Hard reboot.

[MetroMPG]

Filled up today at 55.3 mpg US / 4.3 L/100 km.


Maybe 60 mpg is do-able if I ever add more mods?

[MetroMPG]

Fumes! Here's my new ~50-55 mpg cheat sheet:

[mpg_numbers_guy]

This is ingenious. Should've had something like that on my Civic.

[MetroMPG]

Well, ingenious is a bit strong.

Anybody remember EM member kroushdb? He had a Civic VX in the pre-MPGuino days, and used a digital multimeter to note the resistance of his tank fuel gauge sender, which he would plot against his trip odometer at the end of each day's commute!

Dan's a clever person.

(He's also the first person I knew who described what pulse & glide was. I remember thinking, at first, "but that makes no sense!")

[mpg_numbers_guy]

Maybe I appreciate it more because I was always struggling with my Civic's fuel gauge to estimate what my tank level was at. I could get within 10 MPG of what it was, maybe 5, but any form of accuracy was non-existent.