Hello everyone. I'm a 23 year old computer programmer and I enjoy squeezing MPGs out of my Cavalier. I also own a Porsche, but that car is strictly for fun and wasting money on.
I'm quite good with electronics and have been programming AVR microcontrollers since 07. I made a simple controller board for my Cavalier's IAC motor to try and lower the idle, but I was unsuccessful. The board worked just fine, but the ECU switching from lean to rich made the reduced idle wander. The next microcontroller project I want to tackle is a board that will take over the fuel injection tasks of the ECU. Once I can take full control of fuel delivery, I'll be able to get a few more city MPGs out of the car.
Recently, I've installed a Bosch wideband O2 sensor in the vehicle, mated to a breadboarded circuit that allows me to maintain a 17.5:1 AFR. From a 50 mile round trip, I averaged 42.8 MPG on E10 87 octane gasoline. I could probably do better on pure gasoline, but I can't find any around these parts. I'll build the circuit into the car this week.
I do have a Scangauge II, but I find it to be unreliable since it cannot read injector pulse widths. It's only accurate for a single AFR, and my car can be anywhere from 12.5:1 all the way up to fuel-cutoff. During FCO, the SG reads 0.8GPH, when the engine is burning no fuel. This makes it impossible for the scangauge to reinforce good driving behavior.
A project I want to start is a true MPG meter, one that connects to the #1 injector and to the VSS lines of the car. That way I will have a very accurate MPG rating regardless of air/fuel ratio or fuel cutoff.
I hope to pick up some good MPG tips from you guys
