I recently installed a Continental flex fuel sensor (The smaller of the three models) on my '99 with a VVT swap. I am running a DIYPNP and VVTuner to control the VVT. I have wired in the sensor, plumbed it into the fuel line and have enabled flex fuel. I found some settings on another forum for Microsquirt users for the multiplier settings. I have put about 6 gallons of E85 into the car and driven about 60 miles.

So far the settings seem close enough that even in the cool weather this morning the car started rather easily. A little more fuel loaded than normal, but started. According to my sensor data, my local 93 is actually 11/12% and so far the 5+ gallons of E85 I put in, pushed my percentage up to 50% so far. I plan on topping up the car with E85 and running some autotune to refine it a bit. Currently the car runs very similar to 93 on the 50% mix, a little on the rich side, but not too bad. I suspect it is because my multiplier is set from 0% to 100% and my base tune was actually on something closer to 10%. Some adjustment may be needed to the multiplier based to account for the 10% difference.

When I get home, I will post my MSQ for those interested.

Here is a gratuitous picture of the sensor.!!(Picture not uploading from my phone).