WEIRDNESS!!

[HiProfile]

No offense, but you seem to have done very little research on the tuning deal before jumping in and trying it yourself. Its GOOD that you're asking questions, you'll get the hang of it eventually. First off, you need to understand how AFR's work. 14.7 parts air burned with 1 part fuel is an \"equal\" chemical reaction, no fuel or oxygen is theoreticly unburned. 14.7:1 requires just 3% more fuel to become 14.3:1, so your AFR swings are very small, and normal. *Depending on injector size & manufacturer, the AFR's at lower duty cycles (low load, low RPM) can become slightly erratic. *With different voltages, AFR's can change if you haven't tuned your battery offsets. *When the IAT is reading different air temps than what's actually going into the engine, AFR's will be different. At different temps, air has different density. *Engine coolant temps can also play a part, requiring more fuel at colder ECT temps *Gasoline itself can cause different AFR's, thats one reason cars use O2 sensors now. One gas station could use up to 10% ethanol here in the USA, while the next might use 0%. It also depends on the time of day you get your fuel, as weird as that sounds. FYI the best thing to do is to use the serial port for datalogging the LC-1. I wire mine right to the battery (with fuse), and use the serial port. I get no difference in AFR's depending on where I ground, although I've checked the ground points before, and ALWAYS use an electrical contact spray on all ground points. Remember, aluminum and steel corrode easily which changes resistances, and that makes a HUGE difference in voltage. One other thing - check your plugs, wires, cap, and rotor. As stated, corrosion & wear play a big part, and sometimes old parts will not spark as well (incomplete combustion). Honda recommends replacing plug wires YEARLY, fyi.

[b20beast]

No offense, but you seem to have done very little research on the tuning deal before jumping in and trying it yourself. Its GOOD that you're asking questions, you'll get the hang of it eventually. First off, you need to understand how AFR's work. 14.7 parts air burned with 1 part fuel is an "equal" chemical reaction, no fuel or oxygen is theoreticly unburned. 14.7:1 requires just 3% more fuel to become 14.3:1, so your AFR swings are very small, and normal. *Depending on injector size & manufacturer, the AFR's at lower duty cycles (low load, low RPM) can become slightly erratic. *With different voltages, AFR's can change if you haven't tuned your battery offsets. *When the IAT is reading different air temps than what's actually going into the engine, AFR's will be different. At different temps, air has different density. *Engine coolant temps can also play a part, requiring more fuel at colder ECT temps *Gasoline itself can cause different AFR's, thats one reason cars use O2 sensors now. One gas station could use up to 10% ethanol here in the USA, while the next might use 0%. It also depends on the time of day you get your fuel, as weird as that sounds. FYI the best thing to do is to use the serial port for datalogging the LC-1. I wire mine right to the battery (with fuse), and use the serial port. I get no difference in AFR's depending on where I ground, although I've checked the ground points before, and ALWAYS use an electrical contact spray on all ground points. Remember, aluminum and steel corrode easily which changes resistances, and that makes a HUGE difference in voltage. One other thing - check your plugs, wires, cap, and rotor. As stated, corrosion & wear play a big part, and sometimes old parts will not spark as well (incomplete combustion). Honda recommends replacing plug wires YEARLY, fyi.

thank you very much for the explanation. I feel a lot more confident with tuning. as unbelievable as it sounds i have been reading for about 2 years before i attempted to tune. I guess i am just very anal, and want to make sure i am on the right track.