How to read Ultra Gauge fuel trim data?
Ladogaboy and I have been discussing how to read the UG's fuel trim data, and I think it might deserve a thread of its own.
The UG offers longterm and short term fuel trim readings in percentages over or under 0.00%. Whether that can translate into "lambda" and if so how to do it is the question. Here is how I am thinking of it right now, with Ladogaboy's general, qualified agreement... what do you think? Quoting the Ultra Gauge's manual on the meaning of its fuel trim readouts: "positive values indicate a lean condition exists and the injector is left open longer to compensate, thus adding more fuel" (p.17). Now that means that a UG reading of +1.56% long term fuel trim is 1.0156 lambda, a lean condition, and my car will add more fuel to maintain stoich? That's not good for fuel economy. Better would be negative percentages, indicating rich condition, in response to which the car's ECU will seek stoich by reducing fuel.
Is that correct?
Black and Green's garage entry has abundant detail and notes for Civic modders. I will rebuild this car over decades as parts die--until it becomes a different car of roughly the same shape.
My fuel economy goal is 60-70 mpg while averaging posted speed limits--not the highest possible mileage. I reach the goal when the weather is warmer, and have to slow down when it's colder.