I just built a Jaycar Digital Fuel Adjuster kit and was wondering what is the best sensor to hook it to in an EA Falcon MPI. The kit is primarily made for cars with MAF sensors but it says it can also be used to adjust either MAP, oxy or pretty much any other sensor with a variable voltage output.

What is the main sensor that the ECU uses to calculate fuel requirements to the engine?

Main sensor is the MAP but Ford use a frequency based output so the Jaycar kit won't work. I guess you could use it with the 02 sensor but the results will be limited and soon worked around by the EEC.

The kit also gives you a global voltage displacement, which would be a good starting point if your vehicle is running lean/rich (via O2 sensor). Mind you, check that you have a good earth as .5 volt will have an effect on the readings coming from the oxysensor to the ECU. You may be best off grounding the unit to the engine block rather that the vehicle chassis, though I'd doubt you will achieve any real gains through this method.

why not run it off the voltage line from the Throttle position sensor?

mspw - yeah we actually have it hooked to the TPS at the moment cause of it's variable voltage output. It really is of no benefit though if you think about it as you can achieve the same results just by pressing down on the accelerator a bit more.

edxr8 - yeah I think we fizzled on this one...ah well. I think I spoke to you the other day actally about the wideband 02 sensor??? I got it working btw. it's awesome!

Good to hear you got the WB working, yeah its a great tuning tool. We are currently working on a similar device to the Jaycar kit but for the ford frequency based MAP, hopefully it will help sort out the issues with the I6 runnign rich with larger cams.