Tuesday, March 2, 2010

Using PLX KIWI MPG to reduse fuel consumption

I bought a KIWI MPG trip calculator to be able to measure the fuel consumption in my Citroen Berlingo 2004. My hope was that it would help me learn how to drive the most fuel efficient, and I will give it credit for teaching me a few things. It does, however, have some bugs. Here is my short test and review.

It all started out after reading the tips on Ecomodder.com. Reading, understanding and then following these tips will most likely have the biggest impact on saving you fuel. But I like statistics and to compete with myself using the least fuel. That is why I bought the KIWI MPG.

I plugged the unit into the OBDII port in my car. The KIWI MPG indicated that my car had a "CALP" sensor, which is the one that needs to be calibrated. After some days of driving, I changed the 1.00 value to 0.27 to get fuel consumption close to actual use. Then I have tested it for several months.

It is interesting to see the fuel consumption when driving. Sometimes a try to push the clutch pedal to the floor and just coast, and then compare it to having the enging engaged and running. But can the display be trusted? When going downhill with the gear engaged and no throttle, I have been told that the car should be using no fuel. The KIWI MPG should be showing 0, but it is showing something like 2.4 (liter/100km). Another bug is that the unit does not always start when starting the car. Perhaps as often as 1 out of 3 times it does not start. Then I have to use the on/off switch. When I stop the car, the KIWI MPG does not always stop. It thinks the car is running and the average fuel consumption keeps rising, which ruins the average function. Twice it has gotten some kind of hick-up, showing much too low fuel consumption. Turning it on-off-on brings it back.

The best I can say is that it is an educational toy. After all it is fun, and I have managed to lower my fuel consumption with 5-10% after using it, or is it just because I am using the techniques from ecomodder.com ?

Update: This winter I was not using my car for a week, and after that I could not start it. Flat battery. Then I recalled how I had noticed one morning that the entire windscreen had been covered by a thin layer of ice, except for one small spot. This spot was about a foot above the location of the KIWI MPG. You can feel that the unit is warm even when it is in standby. I have now disconnected the unit, and have had no problems starting the car later this freezing cold winter in Norway. So make sure you unplug this unit if you are not going to use your car for a week or so.

Summary in Norwegian: Har din bil ikke en forbruksmåler? KIWI MPG er en bensinmåler du kan ettermontere i de fleste biler. Imidlertid er jeg noe usikker på hvor godt den egentlig måler forbruket. Det er en morsom dings. Kan kappe kjøre med meg selv til jobben for å se om jeg kan forbedre forbruket fra dagen før. Men jeg er ganske sikker på at det er teknikkene fra ecomodder.com som er det som virkelig monner. Enheten bruker mye strøm i standby, så den bør frakobles hvis du parkere bilen over lenger tid.

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