Need help. MPGuino GPH jumps around.
 

I built an MPGuino and I'm having some problems with it.

I got everything working fine except that when I put it in the car the GPH is all over the place. It will bounce to 0.07 to 10.00 or more. Any ideas on what would cause this?

loose/shorting connection? Wrong connection/circuit? You tried to install it on a lear jet?

what value resistors did you use next to the zeners? And did you use 5 volt zeners?

All secure connections. All hooked into the correct location. Tried Honda Civic VX ( intended car ) and my Honda Insight.

I tried both 50k and 100k resistors. Both zener diodes are 5.1v.

I've also even changed out the Arduino board but get the same result.

Dunno, there is a 94 VX that someone added to the table of car settings, so the circuit and program as described should work. What cpu do you have on your duino?

MPGuino - EcoModder

Using an Arduino Duemilanove (clone) which uses the ATmega328 running at 16mhz.

what version of arduino? What source code (link)? What schematic (link)?

Using version 0022 of the software. Tried using the stock 0.75 version of the MPGuino source that is on the wiki and I also intergrated the save data code in a seprate source. Both give same results. I'm using the arduino schmatic that is on the wiki.

I'll try to post the serial data later tonight. I have not looked at it when in the car. Maybe it will tell us somthing.

you might try the cpp file instead, and without making any modifications first.
http://opengauge.googlecode.com/svn/...no/mpguino.cpp I only tried it once from arduino. You might also try version 11 of arduino like the pde file says.

With the cpp file wont I have to program it with the ISP header? Never done that before. I think I have the nessary equipment to make the cable if needed.

I'll try version 11. I thought it was just so it could fit on the atmega128. I'll try anyway.